Re: [RE-wrenches] Mitsubishi Mini Split fighting with Outback VFX Off Grid
We used to use capacitors, but Dan from Exeltech just poo pooed that fix in another recent thread, so I don't have any other tricks up my sleeve. No poo. Just a cautionary comment. Capacitors connected across the output of an inverter can .. in some circumstances .. cause the voltage control loop to go crazy, resulting in unstable and unpredictable output voltage. Just how much capacitance would cause trouble depends on the inverter design, so I don't have a specific value in mind. And no .. it may not affect all inverters .. or may affect them differently Think of it as a do it at your own risk fix. If it works with one inverter, it may not work with another model and/or brand. Dan On Tue, 10/21/14, Ray Walters r...@solarray.com wrote: Subject: Re: [RE-wrenches] Mitsubishi Mini Split fighting with Outback VFX Off Grid To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Tuesday, October 21, 2014, 12:23 PM The Outback is not a perfect Sinewave. It still has tiny steps in the wave, and when electronics have a problem, its usually with the wave form as it crosses zero voltage . Instead of being instantaneous, it has a few milliseconds of time the wave is at the zero crossing, which can drive some electronics nuts. I don't understand the issue beyond that, but apparently the electronics use the zero crossing for timers and synchronizing, and they're looking for an instant click, not a smear. Do the heat pumps work with the generator? Even though generators can have more harmonic distortion, they do usually have a clean zero crossing. If this is the case, I'm afraid I don't have a cure. We used to use capacitors, but Dan from Exeltech just poo pooed that fix in another recent thread, so I don't have any other tricks up my sleeve. ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Diode Failure
A diode is a diode. ??? Not so. That's like saying a solar panel is a solar panel .. or a tire is a tire. If you can get the identical part # .. then replace it. Don't go out and just use any diode. The diodes in PV are commonly a Schottky barrier diode .. designed to minimize voltage drop, reduce energy loss .. and operate cooler than ordinary diodes when they're conducting. Even something as simple as how they're soldered or otherwise attached is also very important, as that aspect is also used to help dissipate the heat generated by losses within the diode when it's conducting current. To that point, diodes are often rated to operate up to 175C (nearly 2X that of boiling water). Diodes have specific voltage and current ratings. If you can't replace a diode with an identical part .. then you'll have to use as near a match as possible. Never go LOWER in ratings .. but if you go too much above .. it may not work properly (or long-term reliably) either. Corey .. contact me off list with the diode part number and I'll see what I can do to assist. Dan On Mon, 10/20/14, Chris Mason cometenergysyst...@gmail.com wrote: Subject: Re: [RE-wrenches] Diode Failure To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Monday, October 20, 2014, 6:38 PM Corey, A diode is a diode. Get an electronics technician to identify the correct part and source it. On Mon, Oct 20, 2014 at 4:51 PM, Corey Shalanski cshalan...@joule-energy.com wrote: Wrenches, Since my previous post (see below) we have recovered the faulty modules and are now looking to replace the diodes in order to make them functional again. I have had no success sourcing replacement diodes from the original module manufacturer, Mage Solar. Can anyone recommend a source for replacement diodes? -- Corey Shalanski Joule Solar New Orleans, LA ᐧ On Tue, Aug 5, 2014 at 10:27 AM, re-wrenches-requ...@lists.re-wrenches.org wrote: Message: 10 Date: Tue, 5 Aug 2014 09:03:09 -0500 From: Corey Shalanski cshalan...@joule-energy.com To: RE-wrenches@lists.re-wrenches.org Subject: [RE-wrenches] Diode Failure Message-ID: ca+smqz1c7kszuqnvzqr0mmux3f2dt6ydum40iseczr2ejrg...@mail.gmail.com Content-Type: text/plain; charset=utf-8 Wrenches, We recently were contacted by a customer who reported a lightning strike close to his house. His online monitoring revealed that 30 of 35 microinverters simultaneously stopped producing power. On initial visit to the jobsite we measured Voc on many modules - either 12V or 24V instead of rated 36V. On a second visit we discovered that bypass diodes - either 1 or 2 corresponding to observed voltage loss - had failed on each of the faulty modules. My question is: Can anyone support the theory that a nearby lightning flash can cause mass bypass diode failure? -- Corey Shalanski Joule Energy New Orleans, LA ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Quantifying power quality, 50 mf capacitor
Hello Ray, The capacitor across the load trick works in some cases where mod-square-waves are involved, and where high harmonic content is present. You're effectively creating something of a low pass filter, and taking a bit of the edge off of the square waves. A capacitor isn't needed for a true sine wave inverter because the harmonic content is very low already. As Larry mentioned in his post, he wired the capacitor across the load in a manner that when the load was disconnected, so was the capacitor. If you're going to do it .. that's the best way, but be careful just the same. Leaving a capacitor of that size connected at all times is a bad idea. I won't go into detail as to the why?, but suffice to say such explanation is complicated. In simple terms, if an inductive load causes a lagging power factor of X, and a capacitor of appropriate value connected in parallel with the inductive load results in an [essentially] unity power factor, then when the inductive load is disconnected, and the capacitor isn't, you end up with a leading power factor of X .. which is just as bad as the inductive load by itself. That said, a capacitor connected across a mod-square wave inverter will tend to soften the square edges somewhat, and may make certain loads happier .. but the effect on the inverter isn't predictable, particularly where the AC output voltage control circuits are concerned. To say you've been amazingly lucky would be appropriate. Dan -Original Message- From: RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Ray Walters Sent: Sunday, October 12, 2014 16:21 To: RE-wrenches Subject: Re: [RE-wrenches] Quantifying power quality Hi Dan; I, like Larry, must be amazingly lucky then, because we've solved power quality issues for many years with 50mf caps. Usually, its been front loading washers not running on Trace SW inverters, but also Grundfos CP pumps, too. Never had a problem, and some of these have been running that way for over 15 years. I never had a power quality issue with an Exeltech, so I've never used this trick with your inverters. R.Ray Walters CTO, Solarray, Inc Nabcep Certified PV Installer, Licensed Master Electrician Solar Design Engineer 303 505-8760 On 10/12/2014 12:58 PM, Exeltech wrote: Wrenches, Be careful about connecting *any* capacitors across an inverter's AC output. It's not a smart thing to do. While a capacitor may help in some cases when a load has a substantially poor power factor due to significant inductance, there are two serious concerns here: 1. The power factor seen by the inverter will be equally bad in the opposite polarity when the inductive load turns off, and IF the capacitor is still connected across the lines. Larry implied the capacitor he connected was disconnected when the load turned off. 2. Larry shot-gunned a solution. He guessed, and got lucky. We don't know how much actual capacitance was needed in this specific situation. Capacitors connected across an inverter's AC output can destabilize its voltage control loops, leading to erratic AC voltage, resulting in possible damage to the inverter, the load(s) .. or both. Power factor is one of the most misunderstood aspects of electricity. Dan (Professional inverter design engineer .. among other things...) ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Quantifying power quality
Wrenches, Be careful about connecting *any* capacitors across an inverter's AC output. It's not a smart thing to do. While a capacitor may help in some cases when a load has a substantially poor power factor due to significant inductance, there are two serious concerns here: 1. The power factor seen by the inverter will be equally bad in the opposite polarity when the inductive load turns off, and IF the capacitor is still connected across the lines. Larry implied the capacitor he connected was disconnected when the load turned off. 2. Larry shot-gunned a solution. He guessed, and got lucky. We don't know how much actual capacitance was needed in this specific situation. Capacitors connected across an inverter's AC output can destabilize its voltage control loops, leading to erratic AC voltage, resulting in possible damage to the inverter, the load(s) .. or both. Power factor is one of the most misunderstood aspects of electricity. Dan (Professional inverter design engineer .. among other things...) On Sun, 10/12/14, Starlight Solar Power Systems la...@starlightsolar.com wrote: Subject: Re: [RE-wrenches] Quantifying power quality To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Sunday, October 12, 2014, 1:33 PM Hi William, If you recall a couple years ago we had some discussion here about a problem with a specific make appliance being powered by a Magnum inverter. The problem, it was discovered, was the appliance input PF was creating current demands that the transformer based inverter could not keep up with. When I powered the load with a low cost, high frequency inverter, it worked fine. Apparently the HF inverter can keep up with the current changes faster than the Magnum. To fix the problem, a 50mf run type capacitor was installed in the appliance so that it was applied across the AC input when powered on. Everything worked fine then because the cap was taming the wild current created by the low PF. Try looking at the current and voltage waveform together (AC shunt, dual trace scope) at the UPS input. If the current is displaying large spikes and/or is out of phase, you may have found the problem is with a non linear load from the UPS. It may be the SI, like the Magnum, can not keep up and so the UPS input circuits are throwing a fit. Or, something else you can try, connect a high frequency inverter and try to power the UPS. This can be a portable 12 volt battery and inverter. If the problem disappears, well, you take it from there. Larry ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Cooler Modules
Wrenches, Bill Hoffer's comments below are correct relative to hot spots. Mac's comments are also correct relative to overall PV module temperature under open-circuit versus loaded conditions. To Bill's point, if one or more cells are fractured, or buss solder bonds or other connections are defective, the increased resistance at those points will result in significantly increased spot temperatures when current is flowing. The higher the current, the hotter the spot temperature. When no current is flowing, the energy that would otherwise be converted to electricity has to go somewhere .. and in that case it becomes heat. Conversely, buss conductors and connections operate hotter on a localized basis when a PV module is connected to a load. Overall, however, the mean temperature of the entire module is cooler when conducting than when open circuit. Yes, this goes against what one might call intuitive, but it's fact. This was reported in a study conducted by Matt Mueller (et. al.) of NREL. Multiple degradation mechanisms exist within PV modules. Generally, the most common failure mode is associated with thermal cycling. Given the temperature differential between open-circuit and fully loaded module operation, it could be argued there's an effect on overall module life either way, but the effects of either are difficult to quantify. Temperature cycling still remains king in that realm. Additional information is available on the NREL and Sandia websites. Regards to all, Dan Lepinski On Wed, 9/10/14, Mac Lewis maclew...@gmail.com wrote: Subject: Re: [RE-wrenches] Cooler Modules To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Wednesday, September 10, 2014, 11:23 PM Mark, This question depends on what where you draw your system boundary. If you are analyzing a module in its entirety, the module that is converting irradiance energy into electrical current will be cooler overall (less thermal energy) because less of that irradiance energy is turning into thermal energy. However, if you look at individual cells, the module that is conducting current can transfer some of that electrical energy into thermal energy in bad cells, which will make localized heating. Effectively, the modules producing useful work outside of your boundary won't be be converting all of that radiation energy into thermal energy inside of your boundary. Hence, open circuit module warmer than conducting module. This assumes that the only energy entering the system is from radiation, and that energy can leave the system as electrical energy. I like the question On Wed, Sep 10, 2014 at 10:10 PM, William Miller will...@millersolar.com wrote: Colleagues: Thanks for the scintillating and relevant discussion. This brings up a question on my radar: Will unloaded modules fail sooner than loaded modules? Thanks again. Great Group! William Lic 773985 millersolar.com 805-438-5600 From: RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Bill Hoffer Sent: Wednesday, September 10, 2014 9:04 PM To: RE-wrenches Subject: Re: [RE-wrenches] Cooler Modules Mark Loaded modules will have hotter cells. I know this from searching for bad cells with a thermal camera. At open circuit I could not see a difference, but short circuit or loaded I could see 20 - 30 C increase in mismatched cells . Bill ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] PV panel backing
Ron, It's been my experience the only adhesives that work reliably on PV backsheets are those designed for the purpose, such as Dow 804 et. al.. Substances such as silicone sealant, tool polymerics, and others will appear to be suitable when first applied, but they eventually peel loose over a period of 1-5 years. Issue #2: Heat of sufficient temperature to melt the backsheet may also have been hot enough to affect solder joints on and among the cells. Crystallized solder connections will conduct current, but are more resistive, and eventually will degrade due to heating and cooling, leading to overheating and eventual failure. Then too there's a possibility of micro-fractures created in the cells due to the heat, which take time to become apparent, but will also cause a PV module to quit working .. or at least quit working at its rated specifications. Issue #3: When PV are manufactured, the layers at a minimum are manufactured from tempered glass, EVA, cells and buss, EVA, then the backsheet (tedlar, kevlar, etc.), in that order. The module is assembled under conditions of heat and vacuum. With the backsheet melted, the environmental integrity of the laminate has been compromised, allowing ambient humidity into the PV. While it may be functional now, long-term prospects for continued proper operation are questionable at best. Unless there's a pressing reason to try to salvage the module, it's better to replace it. Dan Lepinski On Sun, 8/31/14, Ron Young solarea...@solareagle.com wrote: Subject: [RE-wrenches] PV panel backing To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Sunday, August 31, 2014, 6:32 AM Hello Wrenches, I have an installation of 165w PV on a pole mount that was exposed to a fire from the rear when the customers shop burned. 6 of the 10 panels survived with only replacement of the MC4 plugs required but one of the panels that is still functioning had the rear coating melted off. The cells and electrical grid still function. Can anyone recommend a replacement coating that may salvage this panel for a few more years. I know if left exposed it will soon deteriorate but am wondering if some kind of commonly available non conductive rubberized or latex type of coating might do the job? Ron Young ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Inverters Maximum Input Ratings
Marco, The applicability of your statement ... ... what’s beyond dispute is that when we size the solar array higher than the nameplate inverter output, there will be clipping that takes place….i.e., harvestable solar power that goes nowhere. depends to a great extent on the site climate .. as I'm sure you're aware. Overall, the blanket statement you make in this respect is not correct. Using Hawaii, and 65F/85F as low and high respectively, Solar World SW270 photovoltaic modules will nominally generate 243 watts at 65F, and 225 watts at 85F under conditions of 1 kW/m^2 irradiance and perfectly orthogonal to the sun. Microinverters rated 225 watts AC output at ~95% efficiency will input nominally 237 watts DC. Subsequently, the maximum amount of limiting that could take place under these conditions is approximately 6 watts. However, that too will not happen, as the 65F condition does not occur during mid-day. Since 65F occurs early morning, during periods of decreased irradiance, the sun angle will be fairly low, thus the SW270 photovoltaic modules won't be orthogonal to the sun .. nor will there be 1 kW/m^2 irradiance. Thus the PV module won't be producing 243 watts, but instead will be much less, depending on irradiance and sun angle (among other things). In your own Hawaiian climate, the SW270 is in fact an almost perfect energy match for the Enphase 225. Move the scenario to Phoenix, Arizona, and the cold/hot PV power output (using 5C/40F low, and 50C/120F high), the PV power output would be 249W and 202W respectively, again with 1 kW/m^2 and orthogonal to the sun. The likelihood of 40F during mid-day in Phoenix is exceedingly rare. Thus you can see that the SW270 module is actually a bit UNDERSIZED for an Enphase 225 in Phoenix. The amount of energy not harvested due to limiting in the Phoenix environment is essentially zero, even with a 270 watt PV module. Conversely, the SW270 / Enphase 225 combination in Minneapolis would not be optimal due to the extremely cold winter weather. Here, power limiting within the inverter WOULD occur when cold, resulting in less than 100% of the available DC energy converted to AC at an ambient temperatures of ~50F or cooler, and under conditions of 1 kW/m^2 irradiance with the sun perfectly orthogonal to the PV module. This would not be thermally harmful to the microinverter because it would be taking place during extremely cold weather. Conversely, during summer months, using 35C (95F) as the typical high temperature in Minneapolis, the PV module output would be reduced to 220 watts, all other conditions being equal .. thus LESS than is needed for maximum output by the microinverter. In summary, in warm-to-hot climates, the SW270 would in fact be a nearly ideal match for the Enphase 225 from an energy perspective. Regards to all, Dan Lepinski On Tue, 8/26/14, Marco Mangelsdorf ma...@pvthawaii.com wrote: Subject: [RE-wrenches] Inverters Maximum Input Ratings To: 'RE-wrenches' re-wrenches@lists.re-wrenches.org Date: Tuesday, August 26, 2014, 1:10 AM Look, guys, what’s beyond dispute is that when we size the solar array higher than the nameplate inverter output, there will be clipping that takes place….i.e., harvestable solar power that goes nowhere. The higher that oversize percentage, the more clipping will take place. If the design choice, as noted below, is to use a 270-watt module (from a manufacturer that learned last week that a recall notice was published by the U.S. Consumer Product Safety Commission https://www.cpsc.gov/en/Recalls/2014/SolarWorld-Recalls-Solar-Systems-with-Copper-Grounding-Lugs/ ), does it make sense to use a micro inverter that has a max output of about 225 watts (M215) or 250 watts (M250) when there are micros (e.g., ABB 300) that can handle the full output of the 270 which guarantees NO clipping? marco ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Lightning Damage - Need Replacements (Correction)
Hello Larry, A number of Wrenches have also contacted me off-list asking me to keep them informed. Clearly interest on this topic is high. To that point, I'll gladly post findings and updates here when information becomes available. In reference to his grounds didn't work .. perhaps I ought to have included the words as intended. In another life, I owned a business where we designed and installed photovoltaic-based mountain-top repeater systems for public service and others. Lightning mitigation is of great interest to me as well. Dan On Mon, 6/16/14, Larry Crutcher, Starlight Solar Power Systems la...@starlightsolar.com wrote: Subject: Re: [RE-wrenches] Lightning Damage - Need Replacements (Correction) To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Monday, June 16, 2014, 9:44 AM Hi Dan, You mentioned that “his grounds didn't work”. Actually, they worked, just in an undesirable way. One thing to look at is how or whether the house ground system was bonded to the tower ground. If they were not properly bonded, and with poor soil condition, the potential difference between the two grounds could create very high voltages. The voltage path would be the turbine wiring to find the house ground, traveling through any AC connected items to do so. I would like to hear more about this as it’s a personal subject of study for me. Larry Crutcher ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] AC Coupling Relays
Focus is on the relay contacts. Any good designer will have already incorporated protective diodes for relay DC coils, so nothing needed unless specifically stated in the instruction/installation manual. Do NOT connect any diodes across the relay contacts. Bob Gudgel is 100% on target with his comments (below). Dan On Mon, 6/16/14, Mac Lewis maclew...@gmail.com wrote: Subject: Re: [RE-wrenches] AC Coupling Relays To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Monday, June 16, 2014, 10:59 AM Hi Drake, I think you can put a power diode in parallel to the gt inverter that can conduct that inductive current if you need to. However, I think BoB is correct, there should just be induction of the wiring itself for most grid-tied inverter. The relay engineer recommended this diode for a DC load break application I recently had, so I assume AC would be the same. Thanks On Mon, Jun 16, 2014 at 9:11 AM, b...@midnitesolar.com b...@midnitesolar.com wrote: Since grid-tie inverters sell back with a power factor of 1, the load ~should~ be entirely resistive and not inductive or capacitive so a appropriately rated relay contacts ~should~ be fine. Except maybe if the inverter is designed to supply VARs like the last Solar-Pro magazine talks about. (haven't actually read that article yet but I assume that's what it is about) Of course, others may have different experiences so I would listen to them. I prefer to use a somewhat over-rated relay. boB On 6/16/2014 7:05 AM, Drake wrote: Hello Wrenches, Do the relays that break the current from the direct grid tie inverters, in AC coupled systems, need to be motor rated or can they simply be rated for the amperage of the inverter output? How inductive is the current between the two inverter systems? Will the current tend to jump the contacts on a non motor rated relay, or burn them out prematurely? Thanks, Drake Drake Chamberlin Athens Electric LLC OH License 44810 CO License 3773 NABCEP Certified Solar PV 740-448-7328 http://athens-electric.com/ ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
[RE-wrenches] Lightning Damage - Need Replacements (Correction)
Wrenches, My apologies for an error. When I was given information about the lightning-damaged equipment a few days ago, my friend was understandably a bit rattled after a direct lightning hit to his home, and inadvertently provided incorrect model numbers for the Outback charge controllers. The correct models are listed below. (As an added update, almost everything electrical in his home was destroyed. He said wall cubes for his router and weather stations exploded, with only small pieces scattered around to be swept up.) Thank you. Dan A friend of mine experienced the destruction of major parts of his system in a recent lightning storm. Everything was extensively grounded and protected, but he lives in an area with very high soil resistivity, so good earth ground is very difficult to achieve. (The lightning hit his wind turbine tower directly. Remarkably, his Bergey 10 kW survived, but everything else in his system got fried.) He's looking for: * Two Xantrex XW6048-120/240-60 inverters. They are beyond repair. * One Outback FX60 * One Outback FX80 New-old stock or used but in good working condition units are preferred. (No failed/repaired units please.) If anyone has any of these units available, or you know of any that are available, please contact me off-list. Thank you. Dan Lepinski ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Lightning Damage - Need Replacements (Correction)
Hello Chris, First item of business ... my thanks to Jay Peltz and others for the correction on the Outback charge controller model numbers (again!)! Argh! The CC are are Outback FM60 and FM80. 150Vdc input versions. He needs one each. Apologies for all the confusion. The entire system is built into a custom rack and enclosure in his garage. Granted he may have to change brand/model, but he'd rather not if he can avoid it. He's got a ton of work in it as it is. The system is off-grid north of Fort Worth, Texas. The house and equipment are sitting on and in the worst caliche I've ever seen. It's as close to concrete as you can get. There's virtually no topsoil. Watering grounds won't help .. even poured into a hole. It just sits there. They had to jackhammer to dig the tower hole. He's got a 110' tower for his Bergey. He told me they drove numerous grounds diagonally into the bottom of the tower hole from the edges, bonded them all together, then connected everything to the tower, as well as the other equipment using #4 AWG solid. All of the guy wires are equally bonded. Lightning hit the tower directly, but the fact is .. his grounds didn't work. Everything electrical in the house was destroyed. Didn't matter if it was turned on or off. The only things that DID survive are his batteries (as far as he can tell) .. and the Bergey itself. He connected a three-phase diode array directly to the Bergey output leads, and it's charging his batteries, just not as well as with the controller in place (of course). The genny runs smoothly in the wind, meaning all three phases are intact. If one or two phases were open, you'd see it and hear it in the motion of the blades - much the same effect on the engine if you had a plug wire fall off. If you're a wind person (how can you NOT be in Montana?) .. you already knew that. He may bonded everything to his well casing. I don't know - but I'll ask. This is indeed a good learning opportunity. I'm going to help him get things operating again .. and will highly recommend some of the new lightning protection units Midnite is making. In the meantime .. charge controllers and inverters first. Thanks! Dan On Sun, 6/15/14, Chris Daum ch...@oasismontana.com wrote: Subject: Re: [RE-wrenches] Lightning Damage - Need Replacements (Correction) To: 'RE-wrenches' re-wrenches@lists.re-wrenches.org Date: Sunday, June 15, 2014, 6:00 PM So, was their not enough moisture around the ground rods? That's an issue here, in our semi-arid climate, but I tell people to run their hoses where their grounds areor plug their grounds into their drainfields, whatever works (or attach to well casings, as you all know). Where is the location of this system? Sorry so much stuff burnt up. Lightning is a wierd beast, and it DOES strike twice or even more often in many locations. Chris Daum Oasis Montana From: RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of toddc...@finestplanet.com Sent: Sunday, June 15, 2014 4:53 PM To: RE-wrenches Subject: Re: [RE-wrenches] Lightning Damage - Need Replacements (Correction) on an educational note dan, can you further detail the lightning protection equipment which was incorporated into the system? specifically if spd's were in the system? i have installed several midnight spd's and am curious how they do in real world situations like this. thanks, todd On Sunday, June 15, 2014 2:22pm, Exeltech exelt...@yahoo.com said: Wrenches, My apologies for an error. When I was given information about the lightning-damaged equipment a few days ago, my friend was understandably a bit rattled after a direct lightning hit to his home, and inadvertently provided incorrect model numbers for the Outback charge controllers. The correct models are listed below. (As an added update, almost everything electrical in his home was destroyed. He said wall cubes for his router and weather stations exploded, with only small pieces scattered around to be swept up.) Thank you. Dan A friend of mine experienced the destruction of major parts of his system in a recent lightning storm. Everything was extensively grounded and protected, but he lives in an area with very high soil resistivity, so good earth ground is very difficult to achieve. (The lightning hit his wind turbine tower directly. Remarkably, his Bergey 10 kW survived, but everything else in his system got fried.) He's looking for: * Two Xantrex XW6048-120/240-60 inverters. They are beyond repair. * One Outback FM60 * One Outback FM80 New-old stock or used but in good working condition units are preferred. (No failed/repaired units please.) If anyone has any of these units available, or you know of any that are available, please contact me off-list. Thank you. Dan Lepinski
Re: [RE-wrenches] Lightning Damage - Need Replacements (Correction)
Hello Todd, I forwarded your query to my friend Mike. Waiting for a reply as we speak. He's been a bit slow responding. Repairs are a priority at the moment. Everything electrical in the house was destroyed. As an indicator, he told me the wall cubes for his router and his home weather station were literally blown out of the outlets. I'll update you when I hear back from him. I'm curious to know as well. Whatever he was using .. it wasn't the Midnite SPDs. However, given the magnitude of the direct strike, I'm not sure anything would have survived. Dan On Sun, 6/15/14, toddc...@finestplanet.com toddc...@finestplanet.com wrote: Subject: Re: [RE-wrenches] Lightning Damage - Need Replacements (Correction) To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Sunday, June 15, 2014, 5:52 PM on an educational note dan, can you further detail the lightning protection equipment which was incorporated into the system? specifically if spd's were in the system? i have installed several midnight spd's and am curious how they do in real world situations like this. thanks, todd ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
[RE-wrenches] Lightning Damage - Need Replacements
Wrenches, A friend of mine experienced the destruction of major parts of his system in a recent lightning storm. Everything was extensively grounded and protected, but he lives in an area with very high soil resistivity, so good earth ground is very difficult to achieve. (The lightning hit his wind turbine tower directly. Remarkably, his Bergey 10 kW survived, but everything else in his system got fried.) He's looking for: Two Xantrex XW6048-120/240-60 inverters. They are beyond repair. One Outback MX80 One Outback MX60 New-old stock or used but in good working condition units are preferred. (No failed/repaired units please.) If anyone has any of these units available, or you know of any that are available, please contact me off-list. Thank you. Dan Lepinski ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Module Degradation - voltage or current?
Dana, Excellent question. More than 20 years of PV degradation research conducted by NREL and others has shown the dominant loss to be in the Isc and fill-factor aspects of PV performance due to increasing effective series resistance. Voc stays essentially stable over the life of the PV module. Vmp will decrease over time depending on the severity of the impact on fill factor. With 0.5% average annual degradation in PV wattage, and attributing [say] 80% of the wattage reduction to a decrease in current, the balance of the difference would be a reduction in Vmp. A copy of one such study is here. www.nrel.gov Document: Photovoltaic Degradation Rates - An Analytical Review By: Dirk C. Jordan and Sarah R. Kurtz Journal Article NREL/JA-5200-51664, June 2012 Contract No. DE-AC36-08GO28308 Dan Lepinski On Tue, 6/3/14, Dana Brandt d...@ecotechenergy.com wrote: Subject: [RE-wrenches] Module Degradation - voltage or current? To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Tuesday, June 3, 2014, 5:41 PM Hi Wrenches, Does anyone know what percentage of module degradation over time is voltage and what is current? I'm wanting to make sure we give ourselves plenty of breathing room on the minimum Vmp of the inverters over the long term so need to try to anticipate how much voltage we'll lose on the array over 30 years. Thanks, Dana Dana Brandt Ecotech Energy Systems, LLC www.ecotechenergy.com d...@ecotechenergy.com 360.318.7646 ___ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Halliburton science says solar PV can drain the sun's energy! (SATIRE!)
On Sat, 5/24/14, Jerry Shafer jerrysgarag...@gmail.com wrote: Subject: Re: [RE-wrenches] Fwd: Halliburton science says solar PV can drain the sun's energy! To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Saturday, May 24, 2014, 6:39 PM Wrenches, Its SATIRE! Read this from the Wyoming Star Tribune (a legitimate newspaper): http://trib.com/news/local/state-and-regional/satirical-article-creates-stir-in-wyoming-town/article_bf915e38-98ab-51d5-85f3-9d3825617d60.html And this excerpt from the above-referenced article about the National Report: BEGIN QUOTE: The publication, which reads like the lovechild of Weekly World News and The Onion, offers a disclaimer: “… All news articles contained within National Report are fiction, and presumably fake news. Any resemblance to the truth is purely coincidental.” END QUOTE. Dan Lepinski ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Modified sine deterioration
Hello Drake, As a professional electrial design engineer in the solar energy industry, I can say without hesitation, the simple answer to your question is Yes. Waveforms can deterioriate as components age. Lower-quality capacitors will dry out in 20 years' use (or less!), and this in turn can indeed alter the waveform. You'd need at a minimum a good oscilloscope to observe the waveform. If it's really ragged, and no longer stair-stepped, the inverter is clearly suspect. If it resembles a Pyramid, there may be another issue afoot. Motors connected to modified square wave power turn at lower RPM and operate [sometimes much] hotter than their sine-fed bretheren. Over time, the increased heat takes its toll on the wire insulation in the motor, causing an eventual breakdown of the insulation and a short-circuit of the windings. Presto! Motor BBQ (sometimes inverter too). By the way .. to use quality in context with reference to a modified square wave is quite an oxymoron .. but in this case, it fits. Dan On Tue, 5/20/14, Drake drake.chamber...@redwoodalliance.org wrote: Subject: [RE-wrenches] Modified sine deterioration To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Tuesday, May 20, 2014, 9:24 AM Hello Wrenches, We are diagnosing a system with a 20 year old Trace DR 1512 inverter. Recently a motor burned out that had been running on the system. I do understand that modified sine (modified square) wave inverters are hard on motors in general. My question is, does the quality of the Mayan Pyramid sine wave deteriorate with time as the capacitors dry up, or for any other reason? Would the power quality be expected to have declined on an old unit like this? Thanks, Drake Drake Chamberlin Athens Electric LLC OH License 44810 CO License 3773 NABCEP Certified Solar PV 740-448-7328 http://athens-electric.com/ ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Modified sine deterioration
Hello Jason, Aside from a peek at the mod-square inverter waveform now and then (with an oscilloscope) .. there's nothing more you can do in terms of troubleshooting. Your interval could be a year or more, especially when the product is new. In terms of preventive .. install inverters in a clean, dry, and as room temperature a location as possible. This will help extend the life of ALL of the components. High quality electrolytic capacitors, used within their specifications in well-designed circuits, will wear out very slowly - as in many decades. Drake's mention below is a perfect example. He's working with a 20-year old unit, and parts have improved considerably in 20 years. The electrolytic capacitors will always die early mantra is an urban legend that just won't die. Cheap low-quality parts will die young. So will any other parts used outside of their specifications. Will film capacitors outlive electrolytic capacitors? Yes. Will it matter to you if the electrolytic-based product lives only 40-70 years compared to a film capacitor version wearing out in [say] 70 or 80 years? High quality versions of either part, properly designed into a circuit and used within their respective specifications, will serve the purpose well. Any changes you'll observe in the waveform due to capacitor wear-out will tend to be very gradual, as in years and years. Take a good photo of the 'scope screen, print it, and keep it on file as a before/after reference. Check the wave shape and amplitude (voltage) under identical conditions each time. A simple 100-watt incandescent lamp will help. Turn off all loads except the lamp. Plug in the lamp, attach your 'scope, and take a picture. Fact is, you should do this step for ALL of your installations when new. Keep the printed image with your customer's records. Make a digital backup copy for future use. Ink fades. Refer back to it as needed. While this won't reveal everything that could possibly go wrong .. it's a quick check that may provide some indication of pending trouble. Dan On Tue, 5/20/14, Jason Lerner wapalco@rockisland.comwrote: Subject: Re: [RE-wrenches] Modified sine deterioration To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Tuesday, May 20, 2014, 10:55 AM Hi Dan, I still have 4 Trace U series inverters in the field and have told these customers that they should be saving up for a new inverter for the last 10 years. Is there some preventive troubleshooting I could do before they potentially have the problem Drake is describing, or just die of old age? I have an O scope, but have never actually used it on Modified Sine Wave Thanks, Jason Lerner Waldron Power and Light Co. On May 20, 2014, at 7:54 AM, Exeltech wrote: Hello Drake, As a professional electrical design engineer in the solar energy industry, I can say without hesitation, the simple answer to your question is Yes. Waveforms can deteriorate as components age. Lower-quality capacitors will dry out in 20 years' use (or less!), and this in turn can indeed alter the waveform. You'd need at a minimum a good oscilloscope to observe the waveform. If it's really ragged, and no longer stair-stepped, the inverter is clearly suspect. If it resembles a Pyramid, there may be another issue afoot. Motors connected to modified square wave power turn at lower RPM and operate [sometimes much] hotter than their sine-fed brethren. Over time, the increased heat takes its toll on the wire insulation in the motor, causing an eventual breakdown of the insulation and a short-circuit of the windings. Presto! Motor BBQ (sometimes inverter too). By the way .. to use quality in context with reference to a modified square wave is quite an oxymoron .. but in this case, it fits. Dan On Tue, 5/20/14, Drake drake.chamberlin@redwoodalliance.orgwrote: Subject: [RE-wrenches] Modified sine deterioration To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Tuesday, May 20, 2014, 9:24 AM Hello Wrenches, We are diagnosing a system with a 20 year old Trace DR 1512 inverter. Recently a motor burned out that had been running on the system. I do understand that modified sine (modified square) wave inverters are hard on motors in general. My question is, does the quality of the Mayan Pyramid sine wave deteriorate with time as the capacitors dry up, or for any other reason? Would the power quality be expected to have declined on an old unit like this? Thanks, Drake Drake Chamberlin Athens Electric LLC OH License 44810 CO License 3773 NABCEP Certified Solar PV 740-448-7328 http://athens-electric.com/ ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List
Re: [RE-wrenches] Hijacked Website
Dan (Brown), Some suggestions. #1: In the unlikely chance the website might suddenly go away, get screen shots of everything ASAP. Download and keep copies of each page of the website. This can be done using the Save Page As option (or equivalent) under File. Save all downloaded pages in a separate directory, and make copies onto a thumb drive. Do not edit or alter the page content in any manner. #2: The scammers allege they're a Corporation. Check with your state's Corporation Commission (or equivalent). Claiming corporate status when they aren't incorporated is generally an actionable offense by the State. At a minimum, they can be forced to cease using the Corporation aspect. Action of this nature will be a matter of public record. Subsequently, you could then submit an FOI application to the State to find out whom the State served. #3: Since you ARE incorporated, this is an infringement on your registered company name with the State of Vermont. This too is actionable by the State, but may require attorney participation on your part. #4: Dan FInk's comment pertaining to [in essence] the perpetrators' likely action to attempt to force, cajole, or extort you into buying the domain is very plausible. Sad as it is .. you're going to have to invest some time and money to get a handle on this. Good Luck. Dan (Lepinski) Ever get the impression there are too many Dans involved in this thread? ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] high efficiency modules in U.S.
Hello Jay, They're assembling, using cells from domestic and international sources. Their other components are domestic to the maximum extent possible. Problem is .. like the domestic PV firms mentioned in another post, domestic component manufacturers are also going out of business, forcing procurement from foreign companies. If we don't step up and increase support of our American firms .. there eventually won't be any American firms left to support. Dan On Tue, 4/29/14, jay peltz j...@asis.com wrote: Subject: Re: [RE-wrenches] high efficiency modules in U.S. To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Tuesday, April 29, 2014, 5:36 PM Dan, Are they assembling or actually making cells as well? jay peltz power On Apr 28, 2014, at 8:52 PM, Exeltech wrote: There's also 1Soltech Dallas, Texas. Made in the USA. (Confirmed. I visited their plant on a field trip with a solar energy club not long ago and saw their production line in operation.) They make 60-cell and 80-cell PV ranging from 230W to 350W, and maybe others. They've even got a series of modules that are made with colored cells in red, green, or blue. Not 20%+ (more like 16.0-16.5%) .. but of domestic manufacture .. and available. Been around since 2008. http://1soltech.com/ Dan Lepinski ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] High-Voltage MPPT Charge Controller Needed
Wrenches, Does anyone know of a good quality temperature compensated, three-state charge controller capable of working with a 360 volt battery system? (An equalize mode is also highly desired.) The battery consists of 30 series-connected 12V, 260 A-H deep-cycle sealed lead-acid batteries connected to a 277/480V three-phase inverter in a commercial application. The owner would like to charge the battery with a PV array, not the grid. Subsequently, the controller would need to be capable of working with PV providing up to 600Vdc input to the controller. The PV array does not yet exist, but will be designed to match the controller. Replies on list are acceptable. Thank you. Dan Lepinski ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Capacitive Discharge Test Results
Corey, I'm not pro nor con one way other another on the use of the 1M resistor Chris mentioned in the system you described. However .. if you DO end up following his suggestion .. there are precautions you'll need to observe: 1. Resistors have a maximum voltage rating. Make sure the resistor you use is rated at least 2 kV to prevent arc-over or similar. I'd recommend 5 kV. 2. Though 1 milliamp is a small amount of current, 1000V x 1 mA = 1W. Use a resistor rated at least 2W. I'd recommend a 5W. There's more info we could exchange. This is a start. I wish we had a way to hold a big conference call to discuss the issues you're experiencing, along with several related items, including the somewhat rhetorical question Erika posed. To her query .. unless the PV system is bipolar by design, the array [typically] can NOT be grounded on either leg when used with a transformerless inverter. At a minimum, to ground one leg would defeat the ground-fault detection circuitry in the inverter and hopefully cause it not to operate. Worst case, grounding one PV leg will open fuses, trip circuit breakers, and blow up transistors. The operative word here: typically. There may be a strange topology out there that would be an exception .. but I'm not aware of any. Dan On Fri, 3/28/14, Chris Mason cometenergysyst...@gmail.com wrote: Subject: Re: [RE-wrenches] Capacitive Discharge Test Results To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Friday, March 28, 2014, 3:30 PM If you are using a high resistance meter, you may be experiencing phantom voltages. Here's a Fluke paper on it. http://support.fluke.com/find-sales/Download/Asset/2105317_A_w.pdf You might also discuss with the manufacturer putting a 1M ohm resistor from the center of the strings to the grounded roof to bleed off any stray voltage. It would only bleed 1mA at 1000V so it would not affect performance. Usually this voltage is apparent when the strings have not connected to the load. On Fri, Mar 28, 2014 at 3:41 PM, Corey Shalanski cshalan...@joule-energy.com wrote: Fellow Wrenches, We recently commissioned a 220kW rooftop PV system and are having some inverter malfunction issues. The system details are as follows: - Inverters: Power One Aurora Trio-27.6 (x7) - Modules: Stion STN-130 (x1690) - Array: Strings of 14-16 modules each, 8 strings per combiner, 1 combiner per MPPT input It has been less than two months since we commissioned the system, and we have already seen five of the inverters malfunction. While troubleshooting these issues the inverter manufacturer had me measure positive-to-ground and negative-to-ground voltage readings. At the inverter level I measured instantaneous voltages of 100-200V before seeing a bleedoff; at the string level the voltages were 10-20V before bleedoff. The inverter manufacturer is concerned with the magnitude (~200V) of this instantaneous voltage and also the delay in bleeding off to zero - after about five seconds the voltage level was still approximately 50V (but still dropping). The manufacturer is claiming that this residual voltage should drop to zero much more rapidly AND the presence of such a delayed bleedoff indicates significant leakage coming from the array.They are further claiming that this leakage is responsible for the damage to the inverters. They suggested using a megger to test insulation resistance throughout the installation. My questions to the group: - Is there any truth in the inverter manufacturer's claims? - Do my field measurements seem out of range from what others are seeing with ungrounded arrays? Thanks for any information you can provide. -- Corey Shalanski Joule Energy New Orleans, LA ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] NEC 690.10(C) talking points
... we've found that running a 240 welder off 2 stacked Trace SWs gives a lot more oomph than off a 6kW generator. Altitude is indeed a factor. So too is the vastly superior transient response of the inverter compared to a genset. Poor transient capability is one reason (of many) that make gensets a lousy power source at outdoor concerts. Dan On Thu, 3/20/14, Dan Fink danbo...@gmail.com wrote: Subject: Re: [RE-wrenches] NEC 690.10(C) talking points To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Thursday, March 20, 2014, 8:10 AM Hello all; Thanks for clearing that up. My potential client was reading the Mike Holt book that has slightly different wording than NEC, asked the question, and it confused me. I'll let him know that section simply allows us to use 120/240 panels with a single 120v inverter. Interestingly enough, at our off-grid shop we've found that running a 240 welder off 2 stacked Trace SWs gives a lot more oomph than off a 6kW generator. Being at 8200 ft elevation doesn't help the generators performance either. Dan Fink ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Unusual problem with SMA TL inverter on metal roof
Do NOT connect chokes from any of the PV leads to ground. It will create a DC path where no DC path should exist. It's hazardous, and can/will destroy the inverter. Inductance is indeed an offset to capacitance in many situations .. but this is not one of them. Dan Lepinski Professional Inverter Design Engineer (among many other things...) On Fri, 3/14/14, Chris Mason cometenergysyst...@gmail.com wrote: Subject: Re: [RE-wrenches] Unusual problem with SMA TL inverter on metal roof To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Friday, March 14, 2014, 9:07 AM Typically when capacitance is a problem, the answer is inductance. Have you looked at adding some chokes between the DC negative and ground to counteract the capacitance? On Thu, Mar 13, 2014 at 10:31 PM, Marco Mangelsdorf ma...@pvthawaii.com wrote: Friends, We have run across an odd technical problem at our commercial install at a laundromat on our island. Attached is the description of the issue from SMA. We don’t know much except that we are switch out the TL inverters to the old style US inverters because SMA has no fix for the phantom ground tripping. The issue is beyond our feeble understanding. Any observations to share? Thanks, marco ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Uni-Solar, Kaneka.now Panasonic?
Larry, As August pointed out, there are too many variables related to PV performance to focus on just one and call it good. He's right on target. For a very simplistic example... One aspect of PV performance relates to cell temperature, which in turn is affected by the NOCT rating of the PV. NOCT (nominal operating cell temperature is an indicator of a PV module's ability to dissipate unwanted heat. Higher values of NOCT indicate a module that will have hotter cells than PV with a lower value for NOCT (all other things being equal). Let's say you're comparing two PV that have similar temperature coefficients, but different values for the NOCT. PV 'A' has a slightly worse temperature coefficient, but a lower NOCT than PV 'B'. On paper, looking only at the temperature coefficient, it would appear PV 'B would outperform PV 'A'. However, in this example, PV 'A' would be operating at a lower cell temperature due to its superior ability to dissipate heat. The ultimate cell temperatures of PV 'A' may be sufficiently cooler than PV 'B to allow it to equal or even slightly outperform PV 'B. Incidentally, NOCT is measured and reported by the NRTL during certification. The manufacturer simply prints this value in their PV specs. As with anything .. your mileage Dan On Fri, 3/14/14, Larry Crutcher, Starlight Solar Power Systems la...@starlightsolar.com wrote: Subject: [RE-wrenches] Uni-Solar, Kaneka…now Panasonic? To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Friday, March 14, 2014, 10:33 AM Wrenches, What high performance PV modules are being sold in the US? I can't find Panasonic modules anymore. I have written to them twice but they can't direct me to any distribution in the US. They insist that Sunwize will have them but Sunwize says they have no plans yet to purchase again. From what I can tell, the next best thing is Sunpower modules with -0.38% /K temp coefficient. Are there any others to consider? Larry Crutcher ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Uni-Solar, Kaneka.now Panasonic?
Jesse, Look at the NOCT temperature specification for the PV module(s) of interest to you. The lower the number, the better a module dissipates [unwanted] heat. As previously mentioned, this value is measured and recorded by the NRTL during UL1703 certification. Dan On Fri, 3/14/14, Solar dahlso...@gmail.com wrote: Subject: Re: [RE-wrenches] Uni-Solar, Kaneka.now Panasonic? To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Friday, March 14, 2014, 12:44 PM Can anyone point to data that compares module construction and it's ability to dissipate heat? I've installed many silicon energy (glass on glass) modules and when doing so in the summer it's been hard to touch them due to the glass being so hot. The other manufacturer here in MN (TenK) uses an aluminum back and they claim this dissipates heat better them typical module construction. For a test last summer I installed a few silicon energy modules with Tigos. I never saw their 190W module produce over 154W (tilt of 35 degrees, straight south) not exactly scientific, but thought the glass on glass construction might be at work. Jesse Sent from my iPhone On Mar 14, 2014, at 12:24 PM, Exeltech exelt...@yahoo.com wrote: Larry, As August pointed out, there are too many variables related to PV performance to focus on just one and call it good. He's right on target. For a very simplistic example... One aspect of PV performance relates to cell temperature, which in turn is affected by the NOCT rating of the PV. NOCT (nominal operating cell temperature is an indicator of a PV module's ability to dissipate unwanted heat. Higher values of NOCT indicate a module that will have hotter cells than PV with a lower value for NOCT (all other things being equal). Let's say you're comparing two PV that have similar temperature coefficients, but different values for the NOCT. PV 'A' has a slightly worse temperature coefficient, but a lower NOCT than PV 'B'. On paper, looking only at the temperature coefficient, it would appear PV 'B would outperform PV 'A'. However, in this example, PV 'A' would be operating at a lower cell temperature due to its superior ability to dissipate heat. The ultimate cell temperatures of PV 'A' may be sufficiently cooler than PV 'B to allow it to equal or even slightly outperform PV 'B. Incidentally, NOCT is measured and reported by the NRTL during certification. The manufacturer simply prints this value in their PV specs. As with anything .. your mileage Dan On Fri, 3/14/14, Larry Crutcher, Starlight Solar Power Systems la...@starlightsolar.com wrote: Subject: [RE-wrenches] Uni-Solar, Kaneka…now Panasonic? To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Friday, March 14, 2014, 10:33 AM Wrenches, What high performance PV modules are being sold in the US? I can't find Panasonic modules anymore. I have written to them twice but they can't direct me to any distribution in the US. They insist that Sunwize will have them but Sunwize says they have no plans yet to purchase again. From what I can tell, the next best thing is Sunpower modules with -0.38% /K temp coefficient. Are there any others to consider? Larry Crutcher ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Battery spill containment
I also vote for plastic. Contact Radiant Solar Technology in Ukiah, CA. They make a variety of durable, ventilated HDPE enclosures. http://www.homepower.com/contractors/radiant-solar-technology I've had two of their enclosures in my solar trailer for five years. Well constructed. Zero problems, in spite of their location. Dan On Mon, 3/10/14, RE Ellison reelli...@gmail.com wrote: Subject: Re: [RE-wrenches] Battery spill containment To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Monday, March 10, 2014, 7:05 PM Plastic would definitely work better if you could have access to a shop that can make it Bob Ellison On Mar 10, 2014, at 7:44 PM, Chris Mason cometenergysyst...@gmail.com wrote: Spill containment should be plastic. -Original Message- From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of William Miller Sent: Monday, March 10, 2014 11:57 AM To: RE-wrenches Subject: [RE-wrenches] Battery spill containment Friends: Am I under any obligation to provide a spill containment system under an array of flooded batteries? If so, what do you recommend under a 8' x 11' array of Hawkers? William ___ List sponsored by Home Power magazine ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Flourescent lamps
Mac, Check the power factor on one complete lamp assembly. If you can't test it for yourself, either have someone do it for you .. or contact the lamp manufacturer and get the actual specifications. Some of the new electronic ballasts present a leading power factor, which if sufficiently capacitive (leading PF) .. can cause instabilities in the output voltage control loop of some inverters. (The why is very technical.) Next, contact Magnum and talk with one of their exceedingly knowledgeable engineers. Tell the engineer the real and the reactive aspects of the **entire** load, and ask if this will pose a problem in that particular model inverter. Dan -Original Message- From: On Behalf Of Mac Lewis Sent: March 7, 2014 5:22 PM To: RE-wrenches Subject: Flourescent lamps Hello wrenches, Has anyone used a Magnum PAE 4448 with T8 bulbs. I am putting together a quote that has a significant flourecent lighting load. I haven't heard that this is an issue but I thought I'd check the list. Thanks in advance ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Solarworld diodes
Ron... Bill's comments below are all absolutely excellent and spot-on - particularly his mention about the UL1703 certification. That said .. if you decide to proceed with the repair, I'd like to add a several additional details to the process: 1. Ensure the j-box you purchase is certified by a NRTL as a recognized component for use on PV. Each lab has its own markings to indicate a recognized component. Cheap non-recognized parts may warp or fall apart in time. 2. Install the diode in the correct orientation relative to the PV polarity. The diode should be reverse-biased (not conducting) during unshaded operation of the PV module. 3. The diode current rating Bill mentions below is a *minimum*. If you have a choice between diodes that meet this minimum, or diodes that are rated [say] 25-50% more current than the minimum, opt for the higher-current part. I've seen diodes in j-boxes that were hot enough to boil water (literally) after conducting for a period of time. J-boxes are not conducive to heat dissipation. 4. Make all connections to the diode as solid as possible to minimize the contact resistance. Oxidation in poor connections will cause the contact points to overheat, leading to eventual failure of first the connection .. and then the diode and possibly the other components, including the j-box. 5. Suggestion #5 has two parts: a) Use silicone *adhesive* to attach the junction box to the module. Silicone adhesive is NOT silicone caulk nor silicone sealant. b) Only use a silicon adhesive that's approved for use on PV. Anything less will not stay adhered to the PV backsheet for the life of the PV. Dow-Corning part numbers 737 or 804 are suitable, as are others. The primary difference between the 737 and 804 is the cure time. 804 is faster (~8 hrs vs. 24 hrs), but cost a bit more $ than the 737 last time I bought some. 6. Ensure PV backsheet and the mating surface of the j-box are clean and free of any oil (i.e. from your skin, etc.). Denatured 90%+ alcohol and Kim-wipes (or similar) can be used to prep both surfaces. Dow and others also sell a primer that can be used for this purpose. 7. Apply two long pieces of tape to the box lid in a plus pattern *before* you affix the j-box to the PV. This tape will be used later. Next, apply adhesive to the j-box flange evenly around the entire perimeter. No gaps or thin spots. Press the j-box down evenly, so you get equal amounts of adhesive squeezed out around the entire perimeter of the box. Feed the PV connection tabs up through the opening in the j-box in the process. Finally, use the tape to secure the box in place while the adhesive cures. Do not make any internal connections at this time. 8. After the adhesive has cured .. make all of the connections. Soldered connections (done properly) are superior to crimped or compressive connections. Some j-boxes use compressive connections only. Do your best with what you have. Test and make sure everything is working properly. If so .. congratulations. Dan On Sat, 3/1/14, Bill Hoffer suneng...@gmail.com wrote: Subject: Re: [RE-wrenches] Solarworld diodes To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Saturday, March 1, 2014, 2:20 PM Ron Technically removing the junction box has voided the warranty and the UL listing of the module,field modification is not covered by the manual. Solarworld probably will not accept a warranty claim after the customer has done that. Considering that diode failure is relatively common ( Schottkey diodes are susceptible to surge damage from lightning and near strikes among others), I am disappointing that Solarworld would encapsulate diodes that cannot be field repairable, unless they are using the newer surge resistant switching diodes that have a better chance of a 30 year life ( and cost 10X cheap schottkey didoes). That being said and assuming this is an off grid application that is under the AHJ's radar, there are replacement junction boxes available to salavage the situation, just make sure you check the diode specs and that they exceed the Solarworld diode specs ( I could not find it for that module) . Should be UL listed for the module Max Voltage rating , beware Chinese knockoffs, buy from a reliable source! Rough rule of Thumb, Diode needs to be rated at the max breaker size current + 25 - 50% to account for temperature and current derate. ST has a great application note AN3432 if you want to geek out on the details Look for a solderless clamping terminals or at least one that is spaced off the back of the module to make sure that you do not damage the back sheet when soldering, this connection is critical and a source of future failures in modules from over-heated poor solders. A Larger Junction box is better for heat dissipation with the diode away from the back of the module and to cover
Re: [RE-wrenches] Solaredge inverters w/ backup generator
Chris, Even if a manufacturer agrees with you on incorporating an external shutdown option, don't expect near-term action, especially on existing models. A modification of this nature obviously affects the hardware aspects of an inverter. This alone mandates retesting of at least that aspect of the inverter by the NRTL that issued the original UL1741 certification. If the change also involves software, retesting could be even more extensive. Every model incorporating this feature would be affected. It can take months of waiting in line before equipment can be submitted to a NRTL (depending on the backlog at the lab); and even more months after that for the lab to complete their product review and re-test. If anything fails during the review/re-test process, the clock winds backwards - sometimes to the beginning (depending on the steps required to correct the flaw). While an external inverter disable function may appear to be a very basic and straightforward addition, it's not. In most cases, your request will be more easily incorporated into new designs that haven't yet been certified, than get it added to present production. Personally, I think an interlock on a string system is a reasonable request, and likely to appear in future models from different manufacturers. It's just going to take time. Dan On Fri, 2/14/14, Chris Mason cometenergysyst...@gmail.com wrote: Subject: Re: [RE-wrenches] Solaredge inverters w/ backup generator To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Friday, February 14, 2014, 4:59 AM The Door Open switch is a very useful feature. I am trying to get Fronius to put a digital shutdown terminal on its CL line of inverters, or all inverters preferably. We need to pressure all the inverter manufacturers to provide a logic in or dry contact method of shutdown. Most ATS will provide a N/O dry to indicate position. On Thu, Feb 13, 2014 at 10:21 PM, Jerry Shafer jerrysgarag...@gmail.com wrote: I have done systems in Hawaii, here is one with a 30 k PV system and with a 250k Cummins back up genny. We have a contactor in the ATS that will open if the genny is operating, this in turn sends a door open signal to the Satcon shutting it down I don't want anything effecting the genset operation so with the open created in the ATS it tricks the inverter to shut off safely. We as a policy will not run a genset and PV unless as a AC coupling system and you have some active over voltage like freq and voltage triggers. Jerry ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] California State Fire Marshal's Solar Photovoltaic Installation Guidelines
William, Your frustration with the process is understandable, and quite justified to a great extent. However, to say ... those directly involved in the rule making process..., and alluding to your previous description including industry advocates, is patently unfair. I'm one of those industry advocates. I, along with Bill Brooks and many others on these committees, do our level best to bring some modicum of sanity to an otherwise very insane process. Over the years, I've been to many meetings with industry advocates such as Bill and many others. I've watched as he and our colleagues do their utmost to educate those who would vote these issues upon us in an attempt to help them see the light. A few we win. Many we lose. Problem is, there are more of them than there are of us. Code decisions are frequently made by people who have no direct experience in the solar energy industry, and it shows. In spite of this, Bill, I, and others who ARE from the solar industry continue our efforts from within. As Andrew from Portland proved in his post earlier this week .. even one person in the right place at the right time can make a difference. Your frustration is evident when we hear from you (and others) when you say .. They're supposed to have the public's interest foremost in mind They in this context no doubt references the code committees and the constituent members, including those from our industry. It's just that some of us are on your side, and are continuing the struggle to the best of our ability. Richard Perez said it best in an editorial of perhaps 15 years ago, when code problems back then were as much an issue as they are today. As best I can paraphrase .. .. if this madness continues .. *they* will have us all sitting at home in perfect safety .. in the dark. [Emphasis is mine.] Richard went on to exclude those of us within the solar industry from the ubiquitous they on these committees. The effort continues, but it's an uphill battle at best. The work isn't often visible to you or others, but rest assured, our industry advocates are doing their best under otherwise very difficult circumstances. Regards to all Dan On Fri, 2/14/14, William Korthof wkort...@gmail.com wrote: Subject: [RE-wrenches] California State Fire Marshal's Solar Photovoltaic Installation Guidelines To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Friday, February 14, 2014, 9:42 PM I wholeheartedly concur with the critics here. [rant mode on] I've long been very critical of certain elements of the Electric code...But the state fire Marshall guidelines are approaching outrageous. I feel very let down by the industry advocates, trade groups, and especially those directly involved in the rule making process... They're supposed to have the public's interest foremost in mind---code standards are supposed to be based on the rigorous test that they demonstrably prevent loss of life and loss of property at an economically justified cost. Instead, it seems, the rule-making has advanced to secure a role for continuing stream of proprietary and incrementally more costly safety hardware along with a secure role for those in the process to secure themselves a reliable permanent stream of consulting gigs training and retraining ever more complex and unintelligible code rules. /wk William Korthof 714.875.3576 Sustainable Solutions #956904 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Long transmission line inductance and LED light flicker
Troy, Elsewhere in this thread, boB (Midnite) suggested connecting one of the problematic lights and dimmers directly at the inverter output. This is a very sound recommendation, and would immediately rule in .. or rule out the conductors (and related circuits) as an issue. Another Wrench suggested using an oscilloscope to check the waveform at the load end. This too is excellent advice, and would be even more telling than connecting the lamps and dimmer directly at the inverter. The ‘scope will reveal the AC voltage AND a visual indication of any waveform distortion, either aspect of which could potentially cause the flicker you describe. If you don’t have access to a ‘scope, boB’s comment about connecting at the inverter won’t require any test equipment. At a minimum, set your DVM to record the voltage minimum; connect it the lamp circuit, and turn on the 1 kW load you described. If the voltage is dropping notably, this too would introduce visible flicker. The DVM method is less accurate than an oscilloscope, but better than nothing, and depends greatly on the quality (or not) of your DVM. The above aside, anything else would be strictly conjecture .. which we can do all day, and never be correct. Dan On Wed, 2/12/14, August Goers aug...@luminalt.com wrote: Subject: Re: [RE-wrenches] Long transmission line inductance and LED light flicker To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Wednesday, February 12, 2014, 9:01 AM Hi Troy, Have you double checked that your grounding systems both in the house and at the inverters/array are all up to snuff? Sorry I can’t offer any help with the inductance issue. Best, August From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Troy Harvey Sent: Tuesday, February 11, 2014 5:45 PM To: RE-wrenches Subject: Re: [RE-wrenches] Long transmission line inductance and LED light flicker Richard, The system configuration is: Approx 24.7kW of modules connected to: 2 x 9kW Sunnyboys 1 x 5kW Sunnyboys Plus 4 x 6kW sunnyislands, with 2 Parallel 48V Strings of (12 x 4V Surrettes ) using 350MCM cable Wire The wire is about 1000 feet long 350 MCM in a twisted bundle to this outbuilding Conditions The conditions were during the day with full sun, so during the test there is approx. 47kW of available inverter pointed at only 15 amps (120V) of load(!). The steady state conditions was a few LED lights, maybe 60 watts worth, plus a handful of vampire loads, maybe 100-200 watts total. When a pure resistance load, like a 1000W curling iron was turned on the lights would flicker. Since the lights flickered from a resistive load, but didn't stay dim, I assumed it was from a reactive-phase issues due to the transient turn-on - screwing with the LED dimmer circuits which are already doing a bit of magic to turn TRIAC waveforms into a DC constant current. thanks, Troy Harvey - Principal Engineer Heliocentric 801-453-9434 tahar...@heliocentric.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] DC Solenoid Coil Current
Larry, A latching relay isn't suitable for fail-safe applications. Look into the Kilovac Czonka III EV200HAANA. This series has a coil economizer that reduces coil current (and thus power consumption) after pull-in. Rated coil power is less than 2 watts. Models are good to 900Vdc and up to 500A. Coil inrush current on one model I found is spec'd at 3.8 A for a 130 milliseconds, so you'd need an external transistor to drive it from the computer. If power consumption is a critical aspect, use a suitable MOSFET. If you don't mind wasting another watt or two, a bipolar NPN will also work. The coil current throttles back to less than 100 mA at 12Vdc after contact closure. Because a specialized electronic power supply is driving the coil, Kilovac rates the DC input to the coil driver at anything from 9Vdc to 36Vdc. Here's the Allied page: http://www.alliedelec.com/search/productdetail.aspx?SKU=70062411 Not cheap .. but excellent quality. If you're a registered reseller with Allied, the $ is less. Dan On Tue, 2/11/14, Larry Crutcher, Starlight Solar Power Systems la...@starlightsolar.com wrote: Subject: [RE-wrenches] DC Solenoid Coil Current To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Tuesday, February 11, 2014, 6:43 PM Hello Wrenches, We're preparing to offer Lithium batteries to some of our customers as a replacement to lead acid in recreational vehicles. RV batteries can have multiple charge sources simultaneously so I have worked out protective circuitry to interface with a EMS computer. To insure failsafe operation, I need to install 2 solenoids that will be active 24/7, opening only when fault conditions are met. The solenoids I have looked at (200 amp) have a coil current of about 1 ampere each which equates to 600Wh daily consumption. I'de like to reduce that BUT the computer only provides a +12v or 0 volt state. * Does anyone know of a latching solenoid that will work with a 12v hi/lo voltage state, * OR an interface or circuit for hi/lo to control latching relay * OR a solenoid with a very low quiescent current when on? Many thanks in advance, Larry Crutcher ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Outback Chargers
Bruce, The capacitors may or may not help, and could make things worse. If you've already encountered and solved this exact issue on other identical systems .. carry on. If not ... Switching power supplies have a double-whammy of being non-linear AND reactive. The reactive component is almost always a capacitive front end in the power supply. If the predominent issue happens to be harmonics .. then power-factor correction capacitors MAY help by filtering out some of the higher frequency aspects. If the predominent issue is the reactive front end of the power supply .. caps could make the situation worse. As a side-note, PF correction caps connected across the output of an inverter can cause the inverter's voltage control loop to go unstable, and blow the inverter. Not a guaranteed failure .. but an enhanced possibility. Dan On Mon, 2/10/14, br...@willpowerelect.com br...@willpowerelect.com wrote: Subject: Re: [RE-wrenches] Outback Chargers To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Monday, February 10, 2014, 10:43 PM Matt, I don't have a lot of experience with undersized generators for the application, but I will share some thoughts about my recent experience. Having 3 VFX 3648 on a 12 kw Kohler, the math said I shouldn't have difficulty getting 7 kw total charge current which would put 135 amps into the battery. My experience said the imbalanced load of 2 VFX on one leg and 1 on the other may cause problems. To address that issue I installed an autoformer. The best compromise/solution so far is one VFX on each leg dialed back to 15 amps maximum charge current. This gives 3.6kw total charge current or about 70 amps ~52 volts. The third VFX (master) is programmed at 0 charge but maximum ac. It's only job is to invert or pass through. The two slaves don't have to worry about adjusting for loads, just charging. Why can't we get more power? Switching power supplies in the chargers that create harmonics not readable by your standard amp meter, and that inherently, chargers seem to use only a portion of the sine wave presented to them. Harmonics of several orders induce current into the line and the windings of a generator. Some breakers are also susceptible. In my case, a 70 amp breaker is tripping after a period of time with less than 8kw of charger. I have not yet scoped the line but I suspect the other 50-60% of load is harmonics. Possible solution: I have found some power correction capacitors (600 Kvar @ 480, should give me 300 Kvar @ 240) that I'm going to put in a box and hang on the wall next to the VFX's. The VFX's will get scared and stop doing that! No, seriously, I'll wire the capacitor bank to the ac input busses of the FW 500 and they'll soak up a lot of the ripples that are trying to get back to the generator. It may take a week or so to get back up there, but I'll let you know how it works. ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] -48 Volts at the Phone Company
Keith, Another wrench commented about the Exeltech inverters being capable of working with a -48V battery system. His info was good. The DC input is floating on XP and MX inverters, and may be used in positive-ground telecom battery systems as well as negative ground systems .. such as off-grid, etc.. The MX 120V models are available up to 20 kW, 40 kW in 240V, and 60 kw in 208V three phase. The 120V models can grow incrementally in 1 kW steps; 240V in 2 kW steps; and the three-phase grows in 3 kW steps. You'll have to contact their sales department for more info. By the way .. my own jaded view of kVA ratings .. they're marketing hype to make an inverter look more capable on paper than it really is. Dan On Thu, 1/30/14, Keith Cronin electrich...@yahoo.com wrote: Subject: [RE-wrenches] -48 Volts at the Phone Company To: RE-Wrenches re-wrenches@lists.re-wrenches.org Date: Thursday, January 30, 2014, 10:16 PM Hi folks Any inverters in the marketplace that will happily take -48 volts off the phone companies standard battery banks they use to backup their phone network for us? Client wants to drive a 15kva load and replace and existing conventional UPS system that was rated for 40kva. Thanks Keith Cronin ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Long transmission line inductance and LED light flicker
Troy, You're correct in your statement about dimmers operating on a phase shift within their own circuitry. However, that isn't likely the culprit here. 1000 feet of 350 MCM would have approximately 0.65 millihenry inductance per conductor. If the conductors are widely separated in a manner that the respective magnetic fields have minimal interaction, this inductance value essentially doubles. If the conductors are adjacent, or nearly so, the inductance value is less by virtue of the field cancellation. Parallel conductors in very close proximity to each other will have minimal inductance because the fields are 180 degrees out of phase, and thus cancel. That said .. and presuming a worst case installation with the conductors far apart from each other (not likely .. but we'll pretend that's the case), the collective impedance of both conductors at 60 Hz would be approximately 0.5 ohm. (Inductive reactances add in series.) The remaining calculations pertaining to reactive voltage drop and phase shift depend on additional values that were not present in your post. However, the values above can be plugged into calculations for you to determine the electrical effect. If you were to attempt to cancel the inductive reactance in the conductors, a capacitor of more than 50,000 uF would be required. Clearly NOT recommended. You didn't specify a temperature, so I arbitrarily used 40C (104F) for the wire calculations that follow. 2,000 feet of 350 MCM at 40C would have a collective resistive loss for two conductors of 0.127 ohms. Presuming a 40 amp load, this equates to a 5.1V drop in line voltage. You also didn't indicate whether this was 120V or 240V .. but based on your query, I presumed the former. If so, a 5V drop (and this drop would be in addition other loss in the connections, connectors, switches, breakers, and elsewhere) may be sufficient to cause a slight but visible flicker in some LEDs on dimmers. This would be attributed to the change in time at which the diac (trigger element in the dimmer) is activated relative to time, thus turning on the dimmer at varying points in the wave form .. hence causing a difference in intensity from one cycle to the next. As a point of clarification: aside from the miniscule resistive loss in their conductors and conductive material, capacitors do not have any real power draw. However, inverters can easily be destroyed by sufficient capacitance connected across their AC output. This is not due to the reactive current .. but instead by destabilizing the inverter's output voltage control loop. In summary .. is your problem due to inductance? Not likely. Check for undiscovered points of resistive loss in your circuit. Regards, Dan Lepinski On Sun, 2/2/14, Troy Harvey tahar...@heliocentric.org wrote: Subject: [RE-wrenches] Long transmission line inductance and LED light flicker To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Sunday, February 2, 2014, 2:39 PM We've got a PV system that has long lines from the inverters to the house (1000 ft or so). While the wires are properly sized (2x350MCMs), it inherently has a lot of inductance due to the line-length. What We are noticing is that dimmable LED lights flicker anytime a new load turned on, even if that load is purely resistive and the overall current draw is small (20 amps or so). What I think is happening is the LED dimmer circuits get their cue from phase delays, and that the inductance of the line length causes some phase jitter everytime a load is applied - thus causing flicker. Has anyone dealt with this issue successfully (other than switching to incandescent lights)? Would a static capacitor bank at the house do the trick, or do we need some type of active PFC? And if static did you have any issues with constant power draw from the capacitors? Troy Harvey ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] NEC 2014 690.12 Rapid Shutdown
Brian, UL1741, Section 64.11 stipulates the discharge time for capacitors at less than five minutes. Though the context of this Section specifically addresses capacitors that are accessible by some aspect of inverter disassembly, it would also be appropriate to extend its applicability to DC terminals across which capacitors are connected and are otherwise accessible by an external means, such as DC conductors. Dan Lepinski On Fri, 1/31/14, Brian Mehalic br...@solarenergy.org wrote: Subject: Re: [RE-wrenches] NEC 2014 690.12 Rapid Shutdown To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Friday, January 31, 2014, 1:52 AM What about the capacitors on the dc side of the inverter? My assumption has been that this capacitance is the reason behind the 690.17(E) labeling requirement. Admittedly I don't understand the discharge capabilities of capacitors, but I've measured their voltage and watched it decay when disconnected from a power source (and heard stories about toss the capacitive-laden ballast to the newbie ha ha...). So the question is, say for a of a roof mounted array and a ground-level string inverter, will additional equipment (either in the inverter or external) be required to isolate the PV/dc circuit conductors from the inverter in order to meet 690.12? Brian Mehalic NABCEP Certified Solar PV Installation Professional™ R031508-59 IREC ISPQ Certified Affiliated Instructor/PV US-0132 PV Curriculum Developer and Instructor Solar Energy International http://www.solarenergy.org On Tue, Jan 21, 2014 at 8:45 PM, Bill Brooks billbroo...@yahoo.com wrote: Brian, The requirement is generic. A listed contactor can meet the requirement. A standard is only necessary for products that want to be innovative in meeting the 30V, 240VA. Killing all power is an option with existing listed equipment. NEC 90.4 does not apply. Bill. ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Very small PV systems for surveillance or other micro loads
+1 on Ray's comment about exact load. +1 on Ray's recommendation of measuring it yourself. +2! on Dan's load creep comment. I own a fairly respectable solar trailer, with adequate power and reserves for many needs. Three years ago, I provided solar power for an environmental chili cook-off fund raiser. Organizers assured me the total load would consist of nine small crock pots for the contestants. The crock pots were rated 140 to 200 watts each, and I was told they'd need power only for two hours to keep the chili hot for judging, and sales of chili to the public afterwards. The chili was to be made at home and brought to the event for judging. I arrived early and set up. At first, it appeared the organizers were fairly close on what they'd told me. 11 contestants, all with crock pots. Close enough. Then some professionals showed up. Bottom line .. 22 contestants (not 9), some with institutional cookers using up to 1800 watts. Total load: 14,500 watts. I had 12,200 watts of sine-wave inverter in the trailer, with 24 kW-h of battery reserve. Peukert was in full effect that day. Even with a 2,500 watt Honda generator assisting, the batteries were dead just as the judging began. Fortunately, the chili was still steaming hot for all involved, so the contest wasn't affected .. but it was a painful lesson learned. Admittedly, I *did* get some very good cups of chili that day .. but the batteries in my trailer paid for it. Ray's and Dan's comments (below) are absolutely 100% on target. Don't trust the customer to tell you what power they need. YOU validate the actual loads .. and hold the customer to it. Dan On Tue, 1/21/14, Dan Fink danbo...@gmail.com wrote: Subject: Re: [RE-wrenches] Very small PV systems for surveillance or other micro loads To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Tuesday, January 21, 2014, 11:26 AM I also see lots of load creep Rayoh, forgot to tell youwe need to add some all-night LED area lighting to the system. It won't use much power.. Dan Fink On Tue, Jan 21, 2014 at 10:22 AM, Ray Walters r...@solarray.com wrote: On these small projects, its very important to nail down the exact load, to keep the pricing sane. I list on the estimate what the system is designed to do; for instance 18 w load 24 hrs/ day. Then if something goes wrong and they are running more than they should you just gently point out that that was not what the system was designed to do. I learned a long time ago, that you can't take name plate power draw numbers, or count on the manufacturer to provide those numbers; you've got to confirm it with your own monitoring equipment. R.Ray Walter CTO, Solarray, Inc Nabcep Certified PV Installer, Licensed Master Electrician Solar Design Engineer 303 505-8760 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] garage door opener interference with enphase
Hello Mac, Your conjecture about radiated interference as the cause is very likely correct. RF is being generated by one or more inverters, and is swamping the garage door opener receiver .. rendering it deaf to the actual transmitter. Corrective action(s) for RF interference requires special expertise - a skill I speculate is not common amongst the wrenches. To make the diagnosis process more efficient, it also requires equipment I would speculate isn't found in wrench toolkits. However, that said, troubleshooting can still be done. It will just take more time. My first comment .. toroids have a specific frequency range over which they can be used. This is determine by the toroid's construction, and isn't always immediately evident from their appearance. For example, toroids that roll off at 10 MHz won't be useful at 200 Mhz. Garage door openers tend to operate in the high VHF to low UHF frequency range. The toroids you use will have to be made for that spectrum. Second, interference can be caused by common mode and/or differential mode signals traveling on the AC wires. Again, the remedial actions are different from each other, depending on the path the interference is following. Third, and most importantly, you need to put the toroids and other suppressive devices as close to the source of interference as possible. This means at the inverters .. not in the panelboard. When you install toroids at the panelboard, you've got all those tens of feet of connecting cable acting as an antenna. It won't take much of an interfering signal to swamp out the signal from the garage door opener. Here are some additional suggestions: 1. With all of the inverters operating, hold the garage door opener right next to the drive unit, and press the open button. If it works, move away 5 or 10 feet and try again. If the cause of non-opening is due to radiated interference from the Enphase array .. putting the opener immediately next to the receiver should override the interference from the inverters. If the door does open with the remote immediately adjacent, then at some point you'll find a distance where it works erratically .. or not at all. 2. A possible step you can try .. it's my understanding the Enphase units can be disconnected from the utility one at a time. If that's the case, disconnect *all* of them, close the AC disconnect, applying power to the power cable. We're looking for the unlikely possibility of a tiny arc at this point. Try the garage door remote at some distance. If it works, then you've effectively exonerated the cable and its connections (for now). 3. Next, connect *one* inverter and try the door remote again. If it opens .. then reconnect inverters back into the circuit one at a time. You MAY find it's just one rogue inverter generating radio frequency interference (RFI). Continue to add inverters until the door doesn't open. When you reach that point, disconnect the most recently connected inverter, and move down to the NEXT inverter in line, and repeat the open experiment again. If the door opens .. continue adding inverters. If it doesn't, it could be the cumulative effect of RFI from multiple inverters. RFI troubleshooting without some sophisticated equipment (such as a spectrum analyzer) is going to be a divide and conquer exercise for you. It's going to be time consuming, but it can be done. Due to the complexity of this situation .. we can discuss your situation in more detail on the phone if you wish. I've posted this initial reply to the group because it's a situation others may encounter .. and the steps to find and attempt to remedy the source of interference are essentially the same. I hope this is of some help to you. Dan Lepinski On Sat, 1/18/14, Mac Lewis maclew...@gmail.com wrote: Subject: [RE-wrenches] garage door opener interference with enphase To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Saturday, January 18, 2014, 7:50 AM Hello wrenches, I have an issue that I am having a hard time figuring out. I have a pending service ticket with enphase but I figured I'd throw it out to all your experience. We have an enphase array mounted on a garage. When the array is on (AC disconnect on) the garage door opener doesn't work at any acceptable range. It works fine when the AC disconnect is off. I have installed two toroids on each circuit. I have moved these toroids around the circuits and it doesn't seem to help. I have moved the garage door breaker to the opposite end of the service panel but it didn't seem to help I am starting to wonder if the interference is radiative as opposed to traveling through the power lines. Has anyone had any issues like this? Were you able to find a solution? I'm not sure how to deal with EM interference, any suggestions would be appreciated. Thanks in advance -- Mac Lewis
Re: [RE-wrenches] garage door opener interference with enphase
Hello Chad, Moving the antenna worked in your example below by separating it away from the interference source, and that is clearly the preferred option (as is oft suggested by FCC Part 15 statements). However, it does leave a possible issue: If there's that much interference emanating from the system, it may also be affecting openers or other devices at nearby homes. I wasn't aware antenna extension kits existed for garage door openers. This would be a MUCH simpler solution to the one I mentioned as long as the above possible issue doesn't exist. To that, I would have one other concern: Does the extension kit increases the sensitivity of the garage door opener (and thus its range)? If not, no worries. If so, it might increase the possibility of unwanted activation by other remote controls. This sounds far-fetched .. but it happened in our neighborhood several years ago, where a garage door opener appeared to be operating on its own, at least until some ham radio friends of the affected homeowner (working with some kind of special receiver) discovered another garage door opener for a home two streets away was the same brand of opener, and it somehow ended up operating with the same set of open codes. When the extension antenna was installed, it increased the range of the receiver, and opened up that can of worms. Thankfully, once the cause was discovered .. the fix was easy. A reset and re-program of was all that was needed. Dan On Sat, 1/18/14, Chad Waits chadwa...@netzerosolar.net wrote: Subject: Re: [RE-wrenches] garage door opener interference with enphase To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Saturday, January 18, 2014, 6:28 PM We found the only solution to work is an antenna extension kit for the garage door receiver. Install the antenna outside of the garage (preferably low on the wall) and it will solve your problem. We've had complaints from almost every installation with modules directly over garage door openers. Some people live with it (for most it's a non issue as the problem is worse in the middle of the day when the array is crankin' and they are not at home) other folks want it solved ASAP. Best, Chad Waits President - Net Zero Solar ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Flickering LED lights on and Outback Dual 7248VFXsystem
If only LED lamps on dimmers are flickering, suspect the dimmers, but this isn't yet certain. This can be assessed by plugging one of the flickering LED bulbs into the same circuit, but use the bulb in a table lamp and plug into an AC outlet to bypass the dimmer. Does the LED bulb still flicker? If so, the dimmer can be exhonerated for now. It also means you have more work to do... Another wrench suggested using an oscilloscope to evaluate the AC waveform. That was THE best recommendation, and should be your #1 task. It will immediately help to indicate the culpret. The waveform should be perfectly sinusoidal. Dimmers rely on a phase shift circuit to turn on the power to the load. If the AC waveform is distorted, it can cause the dimmer to activate erratically, and turn on at different points in each cycle of the AC waveform .. leading to flickering. Pay VERY careful attention to hot and neutral. You want the 'scope probe tip on the hot conductor; and the scope ground on neutral. Make certain the scope is in the Hi-Z mode (some 'scopes have a 50 ohm setting in the probe or elsewhere.) Measure carefully -- and use a ground-buster to isolate the 'scope. (Ground-busters are those three-to-two AC socket adapters originally intended for use where the third-pin ground didn't exist, as in older homes.) Pay careful attention to the cleanliness of the waveform AND the consistency of the amplitude. Either or both out of spec can cause flickering. LED bulbs are significant sources of EMI. EMI = electromagnetic inteference .. aka radio frequency interference .. and can affect AM radio, FM radio, and other receiving devices up to some surprisingly high frequencies. Remedial options are limited here .. and are a topic for a totally separate discussion. Dan On Tue, 1/7/14, Chris Daum ch...@oasismontana.com wrote: Subject: Re: [RE-wrenches] Flickering LED lights on and Outback Dual 7248VFXsystem To: 'RE-wrenches' re-wrenches@lists.re-wrenches.org Date: Tuesday, January 7, 2014, 8:51 AM We have a variety of LEDs, cheap, expensive, etcetera -- but no dimmers. We have shown no sign of flickering in any of them off our Radian inverter. Chris Daum Oasis Montana Inc. From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of toddc...@finestplanet.com Sent: Monday, January 06, 2014 9:10 PM To: RE-wrenches Subject: Re: [RE-wrenches] Flickering LED lights on and Outback Dual 7248VFXsystem the only ones i have on a dimmer are in the bathroom and they flicker. being we are grid tied (GVFX-3648) and the grid is up, i suspect this is because of a bad dimmer/lamp combo. anyone find the RFI from led lamps a problem? i have to shut all mine off when using the 2 meter ham rig. todd On Monday, January 6, 2014 7:56pm, frenergy frene...@psln.com said: Another $.02 I have 2, FX3524's and 35 KWhrs of HUP's behind themjust cleaned and torqued the terminals/cables. I run 6-7 brands, sizes, styles of LEDS and some of them of them flicker while, in my case, the convection oven is running. It quickly pulses (~10-20 times/second) to maintain a temperature. Fridge is DC. The less expensive off-brand LEDs flicker, the big name brands don't. Bill ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Flickering LED lights on and Outback Dual 7248 VFX system
There may also be a technical aspect of the dimmer that's adding to the flicker, depending on the type of dimmer(s) in use. Some dimmers use a device called a silicon-controlled rectifier .. or SCR. They allow only half of the sine wave to pass. Half-wave power wasn't very noticeable when used with incandescent lamps due to the continued glow persistence of the filament. However, LEDs react [essentially] immediately, and the flicker is very apparent. Final thought .. compressors use the most energy during the compression stroke. Actual current draw varies with each stroke of the piston. Check not only the battery connections, but look to see if the loads are on the same circuits as the lamps. If in fact the inverter AC output voltage IS dropping due to DC-side issues .. and the large AC loads happen to share the same circuit as the lamps .. this would make any flicker that much worse. Dan On Mon, 1/6/14, b...@midnitesolar.com b...@midnitesolar.com wrote: Subject: Re: [RE-wrenches] Flickering LED lights on and Outback Dual 7248 VFX system To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Monday, January 6, 2014, 6:25 PM Only during Big load surges ? Could it be current limiting and because LEDs are so fast on and off, you notice the drop in momentary voltage ? Any inverter might do that under the right conditions. Just a thought. boB On 1/6/2014 3:45 PM, Dan Fink wrote: I consider LED flicker as very common when a fridge starts up, but NOT while it's running. Both dimmed and not dimmed LEDs. I see flicker more often on systems with smaller (or aging) battery systems of course. The only particular appliance I have found causing constant flicker here and with my clients is a particular brand of laser printer. And also a subwoofer on the stereo (light show!)a different subwoofer brand solved that problem. Go figure, I have no idea why. Most of my inverters are by Magnum. I have not found much difference with LED brands or dimmer brands. I can see how this could be a problem for your client, Kirpal. None of mine seem to mind a startup flicker, but if its constant that's a big problem. I wish I had an answer for you, but I hope that providing this information helps others. CFLs do not give me the same problem, but of course have their own other problems. Dan Fink, Executive Director; Otherpower Buckville Energy Consulting Buckville Publications LLC NABCEP / IREC accredited Continuing Education Providers 970.672.4342 On Mon, Jan 6, 2014 at 2:48 PM, Jay Peltz j...@asis.com wrote: Dimmers are super specific to light brand/type. You'll have to do the research For now swapping to regular switches should work Jay ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Higher LVR to force full re-charge in small OGPV systems
Jay, You surmize correctly on both points. 12.0V equates to ~50% DOD. The LVD point should be higher. The actual value depends somewhat on the battery type and ambient temperature, but under lightly loaded conditions (e.g. C/30), the LVD should be adjusted for around 12.4Vdc to keep the discharge to 20% or less. Dan On Thu, 1/2/14, jay peltz j...@asis.com wrote: Subject: Re: [RE-wrenches] Higher LVR to force full re-charge in small OGPV systems To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Thursday, January 2, 2014, 7:37 PM Hi All, I've been wondering about the LVD set point for this project and I'm asking what you all think. So far 12.0v has been chosen for the LVD and 13.8 LVR. But IMHO as the PV might do 15-20% at best avg per day, I got to thinking that at 12v, its around 40-50% SOC, so it might be the system could be off for a few days as it recharges. If the LVD was higher then it would bounce around at at higher SOC with a lesser chance of off for days and hopefully at least some lights every day. curious what you think, thanks, jay ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Higher LVR to force full re-charge in small OGPV systems
Eric .. Allan .. and all ... Allan wrote: Re an MPPT controller: Nope, I wouldn't. First, this is equatorial west Africa. It's a tropical climate with hot modules most of the year. MPPT offers the greatest benefit when the voltage delta-T is greatest: cold modules and empty batteries. *** While Allan is correct about deriving maximum MPPT benefit when the PV are cold, at 75W per panel, and 120A-H battery, the PV are undersized for all but very light-duty system usage. Obtaining the maximum possible charge current will help lengthen battery life. If two 12V 40W PV in series could be economically utilized (vs. one 75W panel) .. it's worth considering. Second, any controller with MPPT is more complex, and thus more expensive, than a simple PWM controller. *** Hence my comment at the top of the suggestion list: ... if budget and circumstances permit If not - go with a basic PWM unit and other cost-saving measures. If they're going to hold your feet to the fire on the seven year battery performance requirement, you're going to have to limit the depth of discharge, and also institute other life-enhancing practices. Re temperature compensation: *** Temperature compensation in this application may be a toss-up between fully recharging the battery and obtaining maximum battery life. The choice here could go either way. If it's always warm (or hot), compensation may not be needed. In fact, it may be beneficial to help maximize the recharge if the controller thinks the battery is cooler than it really is, which in turn would push the charge voltage set-point up a bit. Not knowing the environment where the systems will be installed makes this decision an unknown . Also .. and keeping in mind that there are elevated equatorial areas where the weather can be cool .. compensation may or may not be a consideration. To me the other features of the C12 - four adjustable settings, removable knobs and 15-minute reserve - were more important than MPPT. *** There is much to be said for the KISS principle. Re an LED SOC display: agreed just as Dan stated. Is there one that can be programmed to lie a little? (The best of these I ever knew was the Photron Batterylite, gone since around 1998. I wish someone would resurrect that tiny gem.) *** With several hundred units in the mix, I'd think a small design house may be interested. As long as you're at it, how about adding a low-voltage disconnect option into the monitor design .. and perhaps even an audible alarm (with user reset). Each feature adds $ and complexity. If the users will routinely look at such an LED monitor and use power accordingly, neither of these features would be needed. Eric .. there's no singular (or simple) answer to your question. If the project is going to be awarded on a strictly low-bid basis .. and they're adamant about seven year battery life .. you're going to have difficulty meeting their budget AND achieving their system goals. Happy New Year to all Dan On Tue, 12/31/13, Allan Sindelar al...@positiveenergysolar.com wrote: Subject: Re: [RE-wrenches] Higher LVR to force full re-charge in small OGPV systems To: Exeltech exelt...@yahoo.com, e...@solarnexusinternational.com, RE-wrenches re-wrenches@lists.re-wrenches.org Date: Tuesday, December 31, 2013, 10:51 AM Dan and Eric, Now I'll respectfully argue with some of Dan's suggestions: Re an MPPT controller: Nope, I wouldn't. First, this is equatorial west Africa. It's a tropical climate with hot modules most of the year. MPPT offers the greatest benefit when the voltage delta-T is greatest: cold modules and empty batteries. No chance for the former, and we're trying to get around the latter. If these systems were going to a cold climate I'd agree with you. Second, any controller with MPPT is more complex, and thus more expensive, than a simple PWM controller. Given the expressed competitive-bid budget limitations, MPPT is not a smart place to allocate costs. Dan is right about the weak C/rate. Spend the money (if you can) on a second or larger module. Re cool batteries: agreed, although I don't know how to achieve this. Re temperature compensation: as much as I push it strongly here, it may not matter in this case, and may be a hindrance. What's the annual ambient temperature swing? Again, if it's equatorial lowlands the temperature may stay around a constant 80º all year. If so, TC is irrelevant. And they occasionally fail, which can cause settings to mess up. Once again, decide if the added cost is worth it in this application. Re an LED SOC display: agreed just as Dan stated. Is there one that can be programmed to lie a little? (The best of these I ever knew was the Photron Batterylite, gone since around 1998. I wish someone would resurrect that tiny gem.) To me the other features of the C12 - four adjustable settings, removable knobs
[RE-wrenches] OFF-LINE: Re: Higher LVR to force full re-charge in small OGPV systems
Hey Mr. Ray ... Aren't you just a gluttony of good info! You're darned handy to have around. I wasn't aware of the Midnite unit. I'll have to scope it out. I'm concerned with Eric's mention of the bid requiring a 120AH battery (~1.5 kWh) .. and only 75W PV. Hopefully their loads are small, of short duration .. and they have plenty of sunlight. The latter sounds iffy from Eric's statement about cloudy days. BZ Products makes a 25A MPPT with a built-in digital voltmeter. Perhaps it could be a two-in-one option for Eric? Stay warm. Happy New Year to you and yours Dan On Tue, 12/31/13, Ray Walters r...@solarray.com wrote: Subject: Re: [RE-wrenches] Higher LVR to force full re-charge in small OGPV systems To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Tuesday, December 31, 2013, 2:01 PM I'll chime back in on a few points: To MPPT or not: It all gets down to the budget: I find the tipping point to be around 250 to 400 watts. My small systems usually don't have MPPT, and as soon as I get into more than a pair of modules, I'm using the cheaper 60 cell modules with MPPT. I like Blue Sky's new PWM 30 amp controller that also includes a digital meter. Temp compensation: it all depends on the temperature variation. If its warm year round, just program the charge settings lower, and as Dan said KISS. Metering: Midnite's Battery Capacity Meter was specifically designed for the African market. Very simple LED smiley face, frowny face reading, It's cheap, and it actually does a decent job of tracking SOC. Its not a Trimetric, but its way better than a volt meter too. R.Ray Walters CTO, Solarray, Inc Nabcep Certified PV Installer, Licensed Master Electrician Solar Design Engineer 303 505-8760 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Higher LVR to force full re-charge in small OGPV systems
Eric, Allan's recommendations on both points are excellent, and spot-on. I would add the following suggestions for your controller and system if budget and circumstances permit: 1) Use a MPPT model controller to enhance the recharge rate under less-than-ideal conditions. The PV is already undersized for the battery you indicated (below). 2) If you get the job .. install the batteries in a location that will keep them as cool as possible. Heat is just as detrimental to battery life as is failure to fully charge. 3) Temperature-compensated charging will enhance battery life. However, the 75W PV vs. 120 A-H battery allows for only a C/20 recharge rate at best. This is not conducive to full recharge on a regular basis unless the loads are very small and are lightly used. If the budget allows for opportunity to double the PV wattage .. it would be wise to do so. 4) A simple stop-light style LED voltage display won't consume much power, but can go a long way toward providing a visual indicator for state-of-charge, especially if it's adjustable, and can be be biased toward a higher SOC (in essence, make it fib a little, and indicate a low SOC sooner than than is actually the case). Worth considering as an option .. but easily omitted to reduce cost and/or simplify the system. I wish you success on winning the project. Regards, Dan On Mon, 12/30/13, Allan Sindelar al...@positiveenergysolar.com wrote: Subject: Re: [RE-wrenches] Higher LVR to force full re-charge in small OGPV systems To: e...@solarnexusinternational.com, RE-wrenches re-wrenches@lists.re-wrenches.org Date: Monday, December 30, 2013, 6:48 PM Eric, Yes, one of the classic problems with small systems and less educated users. Just a small contribution: it would seem to me that in this case the LVD setting is as key as the LVR. What if the LVD was set as high as possible - say, 12.0 V with sealed batteries, along with a 13.8 - 14.0 V LVR. The system would still be run until it shuts off, but the battery remains at a relatively high SOC. The next day the system will return to operation, but with a much higher range of SOC. The users will still experience shutdown, and will over time become familiar with when to expect it and how to live within its capacity, but the battery life will be protected. This approach seems counter-intuitive, but the more I think about it the more sense it makes. The system would also return to operation sooner following cloudy weather - in fact, it would provide a minimal amount during each of the cloudy evenings. Is the C12 still made? It would still seem ideal if so: bulk, float, LVD and LVR, all adjustable, with removable knobs and a 15-minute reserve button after initial LVD shutdown. Rock-solid reliable, too, in my experience. I'd be interested in what approach you select. This intrigues me. Allan Allan Sindelar al...@positiveenergysolar.com NABCEP Certified PV Installation Professional NABCEP Certified Technical Sales Professional New Mexico EE98J Journeyman Electrician Founder, Positive Energy, Inc. A Certified B CorporationTM 3209 Richards Lane Santa Fe , New Mexico 87507 505 424-1112 office 780-2738 cell www.positiveenergysolar.com On 12/30/2013 5:00 PM, Eric Youngren wrote: Hi Wrenches, We are bidding on a project to provide several hundred small (75Wpv, 120AH battery) 12V DC off-grid solar home systems for rural villages in West Africa. The project planners have requested that the systems be designed and built to provide 7 years of battery life. That seems crazy optimistic to me but I'm trying to design the systems that will give the batteries a fighting chance of lasting that long. In my experience with these types of installations, the system users have little or no understanding of how to properly manage their batteries and usually no metering or SOC indication to help them even if they knew what to look for. So, the default control strategy becomes: run the loads until the Low Voltage Disconnect (LVD) turns them off, then wait until the Sun returns and the voltage rises to the Low Voltage Reconnect (LVR) setpoint (around 12.5V is a common default) , upon which point the cycle repeats, with the result that the battery bounces between LVD and LVR, almost never reaches a full SOC, and the batteries are lucky to survive for maybe two years. After that the system will provide a little power during the day while the Sun is shining but the batteries will quickly crash below the LVD after the sun goes down. So, we want to offer a controller with a high LVR setting that will ensure the batteries reach a full recharge after each and every LVD incident.I know the C-12 has an adjustable LVR setpoint and I see one Chinese brand (Manson) that can do it. Does anyone have any other suggestions of small (20A) PWM controllers that can be adjusted to not reconnect
Re: [RE-wrenches] Safely inducing arc fault and ground fault in a completed array
Carl, #1: Under the conditions described by Larry below .. if by some chance the resistor somehow completes a circuit, you'll have up to 10 milliamps flowing through a 40K resistor, and in that case .. up to 4 watts dissipated. To be on the safe side, use a 10W rated resistor just in case there IS a completed circuit. If the array voltage is 500Vdc, use a 50K resistor. If it's 600V .. a 60K ... and so forth. Of greater importance is to ensure you use a resistor that's specified for the rated voltage. Most people aren't aware that resistors have a voltage rating. To be on the safe side, make sure the one you use for this task is rated for 2X the anticipated voltage you'll encounter. #2: Arc faults occur in a variety of forms. Larry did a good job describing them below. They can be manually created with varying degrees of difficulty. One fault to try to create (and the easiest of the list) would be the series fault. Separate a conductor (or connection) between two PV while the system is under load. I recommend using a matched pair of PV connectors with conductors attached, insert them between two PV, and use the conductors themselves as your break point (as opposed to using the existing connectors already on the PV). Separating PV connectors under load will damage the pins and render the connectors unusable if the metal melts (and it could). Be careful! Dan On Mon, 11/25/13, Larry Crutcher, Starlight Solar Power Systems la...@starlightsolar.com wrote: Subject: Re: [RE-wrenches] Safely inducing arc fault and ground fault in a completed array To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Monday, November 25, 2013, 3:55 PM Carl, Assuming about 400 volts, a 40k ohm resistor from PV negative to ground should trip the ground fault. Solder up to some test leads, insulate the resistor and make the short. You'll only be conducting about 2 Watts through the resistor. Arc fault, on the other hand, can be very complex. Series, parallel, inter string and more, pulsed, constant, varying intensity…..it get's beyond my understanding quickly. I'll bow out here and defer to others that are far more educated. Larry On Nov 25, 2013, at 2:04 PM, Carl Adams swingjun...@gmail.com wrote: Wrenches, We just completed an install with the SMA STP12000TL-US. I would like to induce two fault conditions into the system 1) ground fault, and 2) arc fault, in a manner that is both safe to equipment and personnel, in order to see how these units respond to those conditions, and in particular how the arc fault is cleared, after detection. (assuming it is detected) Any suggestions appreciated. With Regards Carl Adams NABCEP 031508-1SunRock Solar ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Square D Disconnects mounted on the slope of the roof.
Wrenches, There appears to be some misinformation getting into this thread. The trip mechanism within standard thermal over-current protective devices (OCP devices) is mechanically spring-loaded, and is triggered by heat. Eric mentions below that Square D breakers are tested in a vertical orientation only - the implication being that's their only UL certified position. If this were true, it would imply the breakers cannot be used in any other orientation. This would potentially limit the Square D OCP market to sub-panels and other enclosures where the devices are vertical. Inasmuch as the vast majority of panelboards I've encountered in my 40+ years in this industry have the breakers stacked horizontally, it would not be a wise business decision for the manufacturer to self-inflict such a limitation on their product. This also does not mean any such limitation (real or not) applies to all breakers. By way of example, OCP devices work in a horizontal position, stacked pancake style in a main panelboard, as well as vertically oriented side-by-side in a sub-panel. In either orientation, they are in full compliance with UL 489, (UL Standard for Circuit Breakers, Switches, and Circuit Breaker Enclosures). If an OCP device *was* positionally-sensitive, UL Standards require this sensitivity to be noted in the documentation accompanying the device. Further to that point, UL 489 Section 7.1.1.13 states: In determining if a circuit breaker complies with the test requirements, the device shall be mounted or supported as in service and tested under conditions approximating those of intended operation, except as otherwise noted. Mounting position notwithstanding, a greater concern would be the ambient temperature of a rooftop location, whereby summer heat would tend to make the OCP device more sensitive than necessary, potentially causing it to trip at an amperage below that of its UL ratings. While a nuisance, a more serious issue arises when operating the OCP device in cold ambient conditions, whereby the device may allow MORE than its rated trip current to flow. Per UL 489, OCP devices are tested at either 25C or 40C ambient. Again per UL 489, if an OCP device is to be used in ambient conditions other than those two ranges, the acceptable temperature range for that OCP device shall be marked on the body of the device. In UL 489, Supplemental Annex, Section 2, Subsection 2.3.3, mechanical vibration testing is conducted with OCP devices oriented vertically, horizontally, and inclined 30 degrees from vertical, with all devices energized up to 200% of the device rated current during the testing. Given the preceding, and per implication of UL 489 testing methods, OCP devices are NOT positionally sensitive. In conclusion, if you DO install a rooftop OCP system, and for proper protection, please ensure the OCP devices utilized are rated for the worst-case ambient temperatures involved. Regards to all, Dan Lepinski At 09:33 AM 11/8/2013, you wrote: Hi Kirpal, All Square D safety switches are UL tested in the Vertical position ONLY, so if someone is trying to install a switch in any other position other than vertical, that will be between them and the inspector. Hope this helps. Eric Eric Bentsen | Schneider Electric | Solar Business | UNITED STATES | Technical Support Representative Phone: +(650) 351-8237 ext. 001# | Email: eric.bent...@schneider-electric.com | Site: www.schneider-electric.com/solar | Address: 250 South Vasco Rd., Livermore, CA 94551 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Using legacy modules on micro-inverters
William, PV temperature coefficient of voltage is a function of the number of cells in series. For 72 cell PV (or two 36-cell PV in series), the coefficient is 2X that of 36 cells. Two SP75 in series, in an ambient temperature environment of -10C, and presuming a cell temperature of -10C at reduced light and a low solar altitude to minimize cell heating, would exhibit nominally 45.4Voc, and 35.6Vmpp respectively. Two SP75 in series, in an ambient temperature environment of 38C, and presuming 1000 W/m^2 orthogonal to the PV module at solar noon, would yield nominally 36.6Voc, and 28.7Vmpp respectively. Nominal cell temperature under the latter circumstances would be 69.3C, presuming a rooftop mount, 6-8 above the roof surface, with 1.5 m/s or less wind speed, and perfectly orthogonal to the sun at solar zenith. Two SQ150 under the identical cold ambient conditions would exhibit 44.4 Voc, and 34.8Vmpp. Two SQ150 under the identical hot ambient conditions would exhibit 36.1Voc, and 28.3Vmpp. Nominal cell temperature for the SQ150 under the latter circumstances would be 70.5C, with the same presumptions as above. Very slight differences exist between two SP75 in series, and one SQ150, but as you alluded to below, they're close enough to be considered essentially identical. Regards, Dan On Mon, 9/30/13, William Miller will...@millersolar.com wrote: Subject: Re: [RE-wrenches] Using legacy modules on micro-inverters To: 'RE-wrenches' re-wrenches@lists.re-wrenches.org Date: Monday, September 30, 2013, 2:24 PM Nick: What is the upper voltage limit for the M250? What happens when that voltage is exceeded? I am trying to use Siemens SP75 modules (two in series) and Shell SQ-150-PC. Below are the specs. Note that two SP75s in series, if you multiply the voltages by two, is identical to the SQ-150 except for the temperature compensation. I am not sure what to do with the temperature compensation value if I put two SP175s insereis. Do you know? Our record low is -10 C and average high is 38C. If I enter the data for the Shell, the calculator shows they are compatible with the M250. Entering the data for two SP75s using -0.077 for Temp Comp (SP75) the tool says not. If I use double (-0.154), then the two SP75s are compatible. What is your determination? Thanks, William From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Nick Soleil Sent: Monday, September 30, 2013 9:56 AM To: RE-wrenches Subject: Re: [RE-wrenches] Using legacy modules on micro-inverters Hi wrenches,The M250 is not limited to 60 cell modules only. The M250 has an expanded voltage window which will allow for it to be paired with a wider range of modules. Enphase has an online module compatibility calculator which can be used for checking a specific pairing in a specific location, at: http://enphase.com/module-compatibility-calculator-m250-update/. Keep in mind that many of the high efficiency, higher voltage, 72 cell modules will not be compatible. ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Li-I question
Ray .. and everyone .. I've been consulting recently on a large off-grid project where the battery price is in the $300/kW-h range for a purchase quantity of 100,000 SCiB cells. That's actually a low cell count compared to the automotive industry. The cells can accept up to 8C charge/discharge without damage over a range of -30C to +55C. The most recent high-performance versions of these cells are spec'd to cycle from 100% to 0% DOD, with a performance reduction of less than 20% from new after 10,000 cycles. Consumer-grade versions of these cells are rated for 6,000 cycles, and I believe are priced accordingly. If you do the math, this is very competitive with the price/performance and energy performance of L-A batteries. They're getting there Regards to all, Dan Lepinski On Mon, 9/23/13, Ray Walters r...@solarray.com wrote: Subject: Re: [RE-wrenches] Li-I question To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Monday, September 23, 2013, 1:10 PM That's almost $2000/ kwh, which is close to 10 times the cost of the best lead acid. That doesn't seem to make sense for solar yet, but it would for electric vehicles because of the weight reduction. Possibly their price has dropped in 2 years? I'm seeing some other sources in the EV world selling 100 AH Li+ cells for about $450/ kwh, which is more like it. R.Ray Walters CTO, Solarray, Inc Nabcep Certified PV Installer, Licensed Master Electrician Solar Design Engineer 303 505-8760 On 9/22/2013 10:14 PM, Kevin Pegg wrote: I did get a quote from Corvus for one project back in Feb 2011. Client hasn't given go ahead yet. 12.4 kWh, ie 2 of their 8D format cells was going to set me back $24,000 CAD. The contract for purchase document is only slightly less complex than purchasing a home. 14 pages worth of. Kevin ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Hawker versusu MK
Several years ago, I designed and built a solar trailer I call the “Solar Shuttle”. ( http://www.ntreg.org/projects.htm ). In it, I use a combination of Rolls-Surette and batteries made by Crown Battery in Ohio. The Rolls serve as the primary batteries for the main inverters. The Crown batteries provide power for three portable solar electric systems ranging in size from 1 to 5 kW (with Exeltech sine wave inverters attached.) Batteries in portable applications such as this are not treated kindly, either mechanically or electrically. Frankly, it’s abusive. In spite of the rough treatment, both the Rolls AND the Crown batteries have done a superb job. By the way, as for “being around for a while” .. Crown has been in business since 1926 .. AND they're made in America. My opinion -- No charge (and no pun intended). Dan On Thu, 8/29/13, Will White william.wh...@realgoods.com wrote: Subject: Re: [RE-wrenches] Hawker versusu MK To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Thursday, August 29, 2013, 9:50 AM I don’t have any experience with this brand of battery but wanted to add my battery story to the thread. I have a bank of Power Battery brand batteries at my house and when I got them the price was right, I had a good relationship with the distributor and the warranty was 10 year (5 full, 5 prorated). A couple of years ago they went out of business and with them went my warranty. At this point I don’t think I’d buy from any manufacture who hadn’t been around for a while. I’d mostly stick with Trojan and Surrette. That’s my $0.02 Thanks, Will __ Will White Regional Field Operations Manager – New England Real Goods Solar 64 Main St. Montpelier, VT 05602 Tel: (802) 223-7804 Cell: (802) 234-3167 www.realgoodssolar.com From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of William Miller Sent: Tuesday, August 13, 2013 3:28 AM To: RE-wrenches Subject: [RE-wrenches] Hawker versusu MK Friends: We are shopping for industrial, flooded, lead acid batteries. We are considering 12 volt packages in the 1800 AH range. Under consideration are: Hawker 12-25W-23S at 1705 AH or MK 106M1033STB at 1896 AH. Have any of you had experience with either, or recommend another option? As always, I am extremely grateful to all of you for the limitless wisdom offered. Sinceerly, William Miller ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Reading material for Off Grid client
Jeremy, It depends on whether she's reading for enjoyment .. learning .. or both. To solve both, I recommend the CD (or is it DVD?) back issues of Home Power Magazine. If she's reading for fun .. point her to Kathleen's past Home and Heart columns. The world of off-grid living from a woman's perspective. Real .. yet with the perfect touch of humor. If your customer is reading for learning .. that's there too. Win-Win. Dan On Sun, 8/18/13, All Solar allso...@scswifi.net wrote: Subject: [RE-wrenches] Reading material for Off Grid client To: re-wrenches@lists.re-wrenches.org re-wrenches@lists.re-wrenches.org Date: Sunday, August 18, 2013, 1:15 PM I am looking for recommendations for some books that I could pass along to a single gal that recently built a new home at which we have installed an Off Grid PV system. Thanks in advance ! Jeremy Rodriguez All Solar ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Mouse pee in the SW
Bill, My short answer is .. if things work after all this .. I wouldn't recommend doing anything to the circuit board after cleaning it. Instead, I'd take steps to keep the mice from ever getting into the inverter again. Long answer... Normally, circuit boards will have been coated with a conformal protective material at the time of manufacture. For those who may not know what conformal coating is, it's a clear polymer liquid (usually silicone based) that's applied to circuit boards, typically as a spray (like spray paint). When dry, it forms a very durable polymer layer that's highly protective against moisture, dirt, and moisture. It's also very electrically resistant, and is accepted by Underwriters Laboratories and other Nationally Recognized Testing Labs as an insulating material. However, unless the circuit board is literally dunked in the liquid conformal material (not done for a variety of reasons), there are always going to be areas on the circuit board (under components, or the back-side of integrated circuit pins away from our view) that are not covered by the conformal coating. Even when conformal coating is well applied, urine can and will still sit on top of the coating and form a conductive path to otherwise unprotected areas of pins and leads. This is what I suspect happened here. Done properly, a distilled water / alcohol bath combination will dissolve and remove these unwanted conductive paths without harming the conformal coating. A concern I still have in this: there may be components on the circuit board that would be damaged or otherwise affected by the water and/or alcohol. Examples would be transformers, switches, relays, etc.. Good quality conformal coating materials aren't affected by water or alcohol, so this procedure is safe to use for cleaning purposes as long as none of the electronic parts themselves would be affected. Parts that have very small distances between their pins, such as microprocessors and similar, are the components most subject to unwanted conductive paths. Another aspect of the circuit board to consider are where through-hole parts are installed, such as relays or other components have leads that penetrate through the circuit board. Such parts can be very difficult to fully seal with conformal coating because the spray simply doesn't penetrate shadowed or hidden locations. One still must be cautious in cleaning a circuit board, as it's possible the water could penetrate the circuit board edges if it's not completely sealed, and either liquid may affect parts on the circuit board itself. As mentioned, this procedure is only if the need is dire .. and replacement isn't an easy option. I'd also be concerned with static electricity issues. I'd wager few if anyone in the Wrench kingdom has the necessary static abatement protections in place. Static electricity can and does permanently damage components, and you'll never know it happened - except the circuit no longer works. Doesn't take carpet either. Did you know you can walk across a tile floor and build up a static charge? (The voice of experience here!) Bill .. to your question: Where would you apply the conformal coating? First .. if it were me, and I were lucky enough to recover from a mouse-pee episode, I'd not use Krylon for this purpose. EVER. In fact, I'd be hesitant to use anything at all. Instead, I'd take steps t protect the hole(s) where the mouse got in so this never happens again. If it's a vent, use metal window screen cut to size, and attach the screen on the inside of the enclosure with a quality silicone adhesive, making sure not to create any electrical or other hazards in the process. (Note I said silicone adhesive, not silicone caulk or silicone seal. There's a difference.) Use fine-mesh screen. Anything larger wont' work. Mice are better than Houdini at getting in and out of tight spaces. (I've seen a mouse flatten its body and squeeze through a louvered vent with less than 3/8 inch spacing.) If you're still totally bent on trying to increase the protection on the circuit board, use a genuine conformal material from a company such as MG Chemicals, Tech Spray, or others. It will be certified to a UL Standard for the purpose. Expect to pay $20-30 for a spray-paint sized can, and it won't be available from any hardware store. Buy it from Mouser, Digi-Key, or similar sources. Get the version with the UV tattle-tale built in. That way, when you spray the board, you can take it outside in bright sunlight and see where the spray exists - and more importantly - where it doesn't. The tattle-tale shows up as a blue-ish or purple-ish color when viewed under ultraviolet light. Before spraying, cover all connectors, connector pins, and sockets. You *don't* want to insulate those. Following the manufacturer's instructions, lightly and evenly coat one side of the board with the conformal material,
Re: [RE-wrenches] Mouse pee in the SW
Hello Jay, For those of us not so adventurous, how well would electrical spray Cleaner work? Good question. I've never used contact/electrical cleaner for this type of task. My guess is, it might work .. but only marginally if at all. Cleaners are solvents intended to remove oxidation and organic films (think oily, as in waxy buildup, etc). Some cleaners also include a silicone or other residual lubricant, which would tend to seal in the remaining contaminents to the circuit board. Not good. Urine, though organic, is water-based, and may or may not dissolve in the spray cleaner. This is why I recommended the distilled water wash, followed by the alcohol rinse. You could try some spray cleaner for this task and report the results to the group.I'm aways open to adding information to my knowledge base. :) (Finding a cooperative mouse may be problematic but I'm sure you can come up with alternatives.) Dan On Fri, 8/16/13, jay peltz j...@asis.com wrote: Subject: Re: [RE-wrenches] Mouse pee in the SW To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Friday, August 16, 2013, 10:39 AM Hi Dan Amazing about what can be done! For those of us not so adventurous, how well would electrical spray Cleaner work? I have used it before to clean a SW that was in a room with a leaky diesel generator. The inside of the inverter was coated in soot, which coupled with sea air, well not such a good combo. It did work after the cleaning though. Thanks Jay Peltz power On Aug 16, 2013, at 5:11 AM, Exeltech exelt...@yahoo.com wrote: Bill, My short answer is .. if things work after all this .. I wouldn't recommend doing anything to the circuit board after cleaning it. Instead, I'd take steps to keep the mice from ever getting into the inverter again. ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Mouse pee in the SW
William, Sounds like the coating on the board wasn't of the best quality. It reacted with the alcohol (which good conformal coatings won't), but has since dried, and should be OK. (The better silicone-based conformal coatings react only with acetone, and then very slowly at that.) Visual appearances aside, as you mentioned .. the circuit board works. Congrats. The powdery appearance won't affect the circuit board or components. However, this is one time where, if after a period of a couple of weeks or so, the circuit board continues to work properly and remains glitch-free, I might suggest purchasing a can of a quality conformal coating and carefully going back over the board (front and back) with a couple of thin layers. On the other hand .. if it ain't broke Dan On Fri, 8/16/13, William will...@millersolar.com wrote: Subject: Re: [RE-wrenches] Mouse pee in the SW To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Friday, August 16, 2013, 1:48 PM Friends: So I tried the experiment below. The board looked pristine when I set it out in the sun to dry but one hour later it looks terrible! It is covered top and bottom by a white, powdery residue. I'll get a photo up on my website. But.. It works The inverter is cobbled together on my tailgate quietly humming. Granted this problem has been intermittent all along so I am still skeptical. If I were to do it again I'd skip the alcohol and dry it slowly and carefully. It is amazing how resilient electronics can be. I even laundered my Bluetooth. I will let you know after I install it if it stop works. William On Aug 15, 2013, at 4:33 PM, Exeltech exelt...@yahoo.com wrote: William, Urine is conductive, and apparently has formed some unwanted electrical pathways between components. This conductivity could easily continue after the board has dried due to humidity in the air. If the need is dire, you can try the following: You will need two 9 x 12 ceramic (Pyrex etc.) cake pans (or of a size appropriate for the PCB); a gallon of *steam distilled* water (not de-ionized, not purified, but steam distilled); and some 91% rubbing alcohol (the 70% variety has too much water content): 1) Remove the contaminated PC boards from the inverter. 2) If there are no water-sensitive components (where water ingress would be problematic), wash (agitate) the board gently in a ceramic pan filled with approx 1/2 to 1 of *steam distilled* water. Nothing less. Water depth should be adequate to submerge and cover the affected area. Do this for approximately 10 minutes. The objective is to dissolve the contaminants. This can take time, especially if in tight areas between components where water doesn't readily circulate. 3) Remove the PCB from the distilled water. 4) Gently rinse the PCB in another ceramic pan filled with sufficient alcohol to at least partially cover the PCB components. The objective here is to displace the distilled water. 5) Put the PCB in a *LIGHTLY* warm oven or a sunny warm location. Allow the alcohol to completely evaporate. This may take time (an hour or more), as the alcohol may have entered various tight areas on the PCB where air doesn't readily penetrate. 6) Once dry, reinstall the PCB in the inverter .. and hope. Follow normal precautions for work with AC power and for static electricity abatement. Be wary of any large high-voltage capacitors that may have retained some charge. Also .. more than one PCB may be affected. And as always .. do so at your own risk. Dan Lepinski Industry Veteran On Thu, 8/15/13, Allan Sindelar al...@positiveenergysolar.com wrote: Subject: Re: [RE-wrenches] Mouse pee in the SW To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Thursday, August 15, 2013, 5:39 PM William, I don't have a definitive answer, but I doubt it's either display or chipset; more likely in the boards. The chips are EEPROMs that contain programming for the firmware; unless there's a bad socket connection from the pee, they won't be affected. The display is pretty much self-contained within its plastic case, and not where the corrosive pee is likely to end up. I'd more suspect circuit board troubles, but I can't tell you which ones. Allan Allan Sindelar al...@positiveenergysolar.com NABCEP Certified PV Installation Professional NABCEP Certified Technical Sales Professional New Mexico EE98J Journeyman Electrician Founder and Chief Technology Officer Positive Energy, Inc., a Certified B CorporationTM 3209 Richards Lane Santa Fe, New Mexico 87507 505 424-1112 office 780-2738 cell www.positiveenergysolar.com On 8/15/2013 3:36 PM, William Miller wrote: Friends: I had a mouse take up residency
Re: [RE-wrenches] Mouse pee in the SW
William, Urine is conductive, and apparently has formed some unwanted electrical pathways between components. This conductivity could easily continue after the board has dried due to humidity in the air. If the need is dire, you can try the following: You will need two 9 x 12 ceramic (Pyrex etc.) cake pans (or of a size appropriate for the PCB); a gallon of *steam distilled* water (not de-ionized, not purified, but steam distilled); and some 91% rubbing alcohol (the 70% variety has too much water content): 1) Remove the contaminated PC boards from the inverter. 2) If there are no water-sensitive components (where water ingress would be problematic), wash (agitate) the board gently in a ceramic pan filled with approx 1/2 to 1 of *steam distilled* water. Nothing less. Water depth should be adequate to submerge and cover the affected area. Do this for approximately 10 minutes. The objective is to dissolve the contaminants. This can take time, especially if in tight areas between components where water doesn't readily circulate. 3) Remove the PCB from the distilled water. 4) Gently rinse the PCB in another ceramic pan filled with sufficient alcohol to at least partially cover the PCB components. The objective here is to displace the distilled water. 5) Put the PCB in a *LIGHTLY* warm oven or a sunny warm location. Allow the alcohol to completely evaporate. This may take time (an hour or more), as the alcohol may have entered various tight areas on the PCB where air doesn't readily penetrate. 6) Once dry, reinstall the PCB in the inverter .. and hope. Follow normal precautions for work with AC power and for static electricity abatement. Be wary of any large high-voltage capacitors that may have retained some charge. Also .. more than one PCB may be affected. And as always .. do so at your own risk. Dan Lepinski Industry Veteran On Thu, 8/15/13, Allan Sindelar al...@positiveenergysolar.com wrote: Subject: Re: [RE-wrenches] Mouse pee in the SW To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Thursday, August 15, 2013, 5:39 PM William, I don't have a definitive answer, but I doubt it's either display or chipset; more likely in the boards. The chips are EEPROMs that contain programming for the firmware; unless there's a bad socket connection from the pee, they won't be affected. The display is pretty much self-contained within its plastic case, and not where the corrosive pee is likely to end up. I'd more suspect circuit board troubles, but I can't tell you which ones. Allan Allan Sindelar al...@positiveenergysolar.com NABCEP Certified PV Installation Professional NABCEP Certified Technical Sales Professional New Mexico EE98J Journeyman Electrician Founder and Chief Technology Officer Positive Energy, Inc., a Certified B CorporationTM 3209 Richards Lane Santa Fe, New Mexico 87507 505 424-1112 office 780-2738 cell www.positiveenergysolar.com On 8/15/2013 3:36 PM, William Miller wrote: Friends: I had a mouse take up residency in an SW inverter (SW4024). It peed on the top circuit board and chewed on one wire, at least that we found. We have had this happen before and solved the problem by cleaning and drying. This time the mouse pee was minimal and cleaned off easily and what appeared to be throughly. However we can't get the inverter to work reliably. Sometimes it works and sometimes it does not. The overload light is solid and the error light flashes. The controls work on some menus and not on others. If I shut the inverter down it won't come back on. I take off the cover, look around, connect and disconnect ribon cables and it comes back on, only to go out a day later. I have a spare display and chipset. I am considering changing out one then the other. Any adivce would be appreciated. As always, I am very grateful to all of you. It seems I have been receiving more advice than I have been giving lately so I look forwards to the opportuntiy to reciprocate. Sincerely, William Miller ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Relay for 48v Vent Fan
Mouser Electronics and Digi-key will also have these relays. You don't need anywhere near that heavy a relay. A fan consuming 6 watts at 48 volts equates to only 0.125 amps. A small relay with contacts rated for 0.5 amp at 48Vdc will be more than adequate. Get a relay with a coil of 500 ohms to 1K (or even higher) to minimize energy usage. Dan On Thu, 8/8/13, jay peltz j...@asis.com wrote: Subject: Re: [RE-wrenches] Relay for 48v Vent Fan To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Thursday, August 8, 2013, 7:09 PM HI Rich, Grainger will have 12v coil relays that will switch 48v. jay peltz powerOn Aug 8, 2013, at 4:49 PM, Rich Nicol wrote: Hello Wrenches, Does anyone have any advice about what to use for a relay to power a 48 volt Zephyr battery vent fan using the 12 volt auxiliary output from the Midnite Classic Charge controllers. The fan only draws 6 watts but my problem is the 48 volt side of the equation. A supplier has recommend a double pole/double throw relay rated for up to 30 amps at 24 volts wired in series. I’m curious if anyone knows of a relay rated for 48volts (actually higher voltage since the fan is signaled to come on when the battery reaches gassing voltage) that would work in this application or if there is widespread agreement that the 24volt rated relay would work fine since we are requiring only minimal current and spreading between two contacts.As always, your input is greatly valued! Thanks,Rich ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org -Inline Attachment Follows- ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Wet NiCad batteries
Jay, I second Bob-O's comment - completely. I inherited a number of pocket-plate ni-cad cells in the early 90s and went through the same exercise as Richard Perez -- including the same bad words he used (maybe more). If the cells are truly diminished in capacity, recycle them. The reconditioning effort required in an attempt to bring them back to life wasn't worth it. You may as well consider a DIY re-cap of your old tires while you're at it. Words of experience from the old guard Dan --- On Tue, 6/25/13, Bob-O Schultze bo...@electronconnection.com wrote: From: Bob-O Schultze bo...@electronconnection.com Subject: Re: [RE-wrenches] Wet NiCad batteries To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Tuesday, June 25, 2013, 11:55 AM You might want to check your early Home Powers. We went thorough that dance in 1989 or so. It's ugly and the spent electrolyte is serious toxic waste. On Jun 25, 2013, at 9:32 AM, jay peltz wrote: HI All, I'm looking for information on how you recondition wet cell NiCad batteries, Thanks in advance, jay peltz power ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] What is this terminal?
Dave, The terminal is a Wago Wall Nut. Per Wago's website, it is UL certified for 600V. Different color plastics for the various connectors to help keep track of various circuits. All have the same UL rating. Link: http://www.wago.us/products/2635.htm Regards, Dan --- On Fri, 6/14/13, Dave Click davecl...@fsec.ucf.edu wrote: From: Dave Click davecl...@fsec.ucf.edu Subject: [RE-wrenches] What is this terminal? To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Friday, June 14, 2013, 8:21 AM All, Could you please help me identify this terminal? Just want to make sure it's 600 VDC rated. Thanks, Dave -Inline Attachment Follows- ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] used panel mount questions
I agree with Allen, and would like to add a related comment. Foam boards are thermally insulative in nature. If affixed to the PV with adhesive, they would cause the PV module to run hotter than if the backsheet was fully exposed to the air. This results in reduced energy output under all conditions, and increased thermal stresses on the PV cells, internal buss, bonds, and other aspects of the PV. Dan --- On Thu, 5/30/13, Allan Sindelar al...@positiveenergysolar.com wrote: From: Allan Sindelar al...@positiveenergysolar.com Subject: Re: [RE-wrenches] used panel mount questions To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Thursday, May 30, 2013, 5:46 PM Todd, I don't have your answers, only the caution that blue foam to many of us with a construction background means extruded polystyrene or blueboard, commonly used around foundations. It deteriorates with exposure to sunlight, so could only be used in an application such as this if protected from UV. Allan Allan Sindelar al...@positiveenergysolar.com NABCEP Certified Photovoltaic Installer NABCEP Certified Technical Sales Professional New Mexico EE98J Journeyman Electrician Founder and Chief Technology Officer Positive Energy, Inc. 3209 Richards Lane (note new address) Santa Fe, New Mexico 87507 505 424-1112 www.positiveenergysolar.com On 5/30/2013 4:14 PM, Todd Cory wrote: wrenches, i have a customer who purchased 20 used astropower ap75 modules. they are frameless and appear to have been previously mounted using four, 2 wide X 10 long strips of blue rigid foam, glued to the back of each module with some kind of adhesive. two questions: this seems to be a reasonable mounting system id like to repeat. would anyone familiar with this kind of mounting technique be willing to comment/speculate on an adhesive that would not degrade the tedlar backsheet? whatever was previously used worked great. what kind of flat/smooth mounting surface would folks suggest the other side of the blue foam be attached to? the only thing i can think of is plywood, but that would rot over time. thanks, todd ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org -Inline Attachment Follows- ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] used panel mount questions
I've seen rack edge clamps for frameless PV advertised, but didn't make a mental note of made by whom, or where I saw the ad. I *do* recall the clamps were intended to be located along the long edges, not the ends. Otherwise, expansion/contraction would stress/break the glass. There's a wealth of knowledge and know-how here. Someone with the answer will chime in. Dan --- On Thu, 5/30/13, toddc...@finestplanet.com toddc...@finestplanet.com wrote: From: toddc...@finestplanet.com toddc...@finestplanet.com Subject: Re: [RE-wrenches] used panel mount questions To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Thursday, May 30, 2013, 6:06 PM good point dan... i wonder how frameless modules are intended to be mounted? todd On Thursday, May 30, 2013 4:00pm, Exeltech exelt...@yahoo.com said: I agree with Allen, and would like to add a related comment. Foam boards are thermally insulative in nature. If affixed to the PV with adhesive, they would cause the PV module to run hotter than if the backsheet was fully exposed to the air. This results in reduced energy output under all conditions, and increased thermal stresses on the PV cells, internal buss, bonds, and other aspects of the PV. Dan --- On Thu, 5/30/13, Allan Sindelar al...@positiveenergysolar.com wrote: From: Allan Sindelar al...@positiveenergysolar.com Subject: Re: [RE-wrenches] used panel mount questions To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Thursday, May 30, 2013, 5:46 PM Todd, I don't have your answers, only the caution that blue foam to many of us with a construction background means extruded polystyrene or blueboard, commonly used around foundations. It deteriorates with exposure to sunlight, so could only be used in an application such as this if protected from UV. Allan Allan Sindelar al...@positiveenergysolar.com NABCEP Certified Photovoltaic Installer NABCEP Certified Technical Sales Professional New Mexico EE98J Journeyman Electrician Founder and Chief Technology Officer Positive Energy, Inc. 3209 Richards Lane (note new address) Santa Fe, New Mexico 87507 505 424-1112 www.positiveenergysolar.com On 5/30/2013 4:14 PM, Todd Cory wrote: wrenches, i have a customer who purchased 20 used astropower ap75 modules. they are frameless and appear to have been previously mounted using four, 2 wide X 10 long strips of blue rigid foam, glued to the back of each module with some kind of adhesive. two questions: this seems to be a reasonable mounting system id like to repeat. would anyone familiar with this kind of mounting technique be willing to comment/speculate on an adhesive that would not degrade the tedlar backsheet? whatever was previously used worked great. what kind of flat/smooth mounting surface would folks suggest the other side of the blue foam be attached to? the only thing i can think of is plywood, but that would rot over time. thanks, todd ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org -Inline Attachment Follows- ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org Sent from Finest Planet WebMail. -Inline Attachment Follows- ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
[RE-wrenches] Adhesives. (Was used panel mount questions)
Wrenches, There are PV-specific adhesives certified for use on backsheets. Examples are: Dow-Corning 737 Dow-Corning 804 Tonsan 1527 and others. These are silicone-based, but NOT at all like what you'd buy from big-box or similar outlets. Consumer-type silicone adhesives such as Ray mentioned will *not* have the long term adhesion to the backsheets. They work for a while, but not 20 years. Any good distributor of adhesives will stock or can get what you need. Here in the Dallas/Fort Worth area we have a company called Krayden. They have warehouse locations around the country, and stock the Dow adhesives I mentioned above. I'm sure there are also other sources. For small jobs, you can buy these PV adhesives in caulk sized tubes that work (where else?) in a caulking gun. Dan ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Battery Boxes
Try: Radiant Solar Technology 500 Milani Drive Ukiah, California 95482 (707) 485-8359 http://www.radiantsolartech.com Several years ago, they made two HDPE enclosures for me that each hold four Rolls-Surrette batteries.. The enclosures have a deep bottom for containing acid, and are ventilated in the sides and top. The side vents are screened to prevent critter entry. Non-conductive. Non-corrosive. Extremely durable. Dan --- On Mon, 5/13/13, Maverick Brown maver...@mavericksolar.com wrote: From: Maverick Brown maver...@mavericksolar.com Subject: Re: [RE-wrenches] Battery Boxes To: RE-wrenches re-wrenches@lists.re-wrenches.org Cc: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Monday, May 13, 2013, 7:54 PM For FLA batteries, we only use plywood for the boxes. I'm worry about corrosion. For AGM, we use metal, usually AL. Stainless is more expensive. Thank you, Maverick Maverick BrownBSEET, NABCEP Certified Solar PV Installer ®President CEOMaverick Solar Enterprises, Inc.Office: 512-919-4493Cell: 512-460-9825 Sent from an iPhone. On May 13, 2013, at 7:30 PM, Jesse Dahl dahlso...@gmail.com wrote: After seeing this battery box and seeing the issues that can arise if a large battery bank is deployed I contacted a local metal fab shop and asked for a estimate on building one if I needed it. A 45x40x 20 battery box with stamped louvers was about $1000. This was made out of stainless because they said rubber wouldn't stick as well to aluminum. Any thoughts on cost and using stainless for this reason? Sent from my iPhone On May 12, 2013, at 9:10 AM, Dan Fink danbo...@gmail.com wrote: Jesse;I too have concerns about wooden battery boxes. Have seen a couple close calls with fires from thermal runaway, and acid doesn't treat wood kindly. But for a large bank, anything commercial is extremely expensive. Our current solution is to caulk the wooden box, line with pink foam sheets if insulation is needed, then line interior with Du-Rock (cement board) and caulk. Don't forget mouse screens. I was always told that battery box lids must be slanted so the hydrogen accumulates at the top, but over the years have found the REAL reason -- it keeps the homeowner from using the battery box as a table for storing junk! LOL For outdoor systems, I've seen some really nice battery boxes made from steel jobsite tool boxes lined with foam and cement board, and some are available with slanted lids. Dan Fink, Executive Director; Otherpower Buckville Energy Consulting Buckville Publications LLC NABCEP / IREC accredited Continuing Education Providers 970.672.4342 On May 11, 2013, at 10:16 PM, Jesse Dahl dahlso...@gmail.com wrote: Hello, I visited a site on Friday to do some trouble-shooting on a system and noticed the battery box was homemade by the installer of the system. Made from lumber. Seems to me like there may be some safety and liability issues with a homemade/lumber battery box. Maybe I'm getting gun shy after hearing sue stories. Is this a common practice? I did some looking and there really isn't a single box that would work for this system so it would've taken two boxes to do it, so that could be why they did it. Thanks as always, Jesse ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org -Inline Attachment Follows- ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette:
Re: [RE-wrenches] not sure what's going on here
Hello Wrench Team, Please forgive as this seasoned design engineer contributes to your discussion: The conditions and symptoms as originally posted are: 1) A PV array consisting of four Solarworld SW165 PV modules. [72-cell, mono PV, Voc=44.1V, Vmpp=35.3V, Isc=5.2A, Impp=4.7A, all values at STC.] All four PV are parallel-connected. (See item #2 for substantiation.) 2) The PV terminate into a Blue Sky Energy 3024i [30A max out, with automatic current limiting]. V input max for this unit is specified to be 57 volts. This maximum voltage would be exceeded by just two of the above-mentioned PV connected in series. Subsequently, my contention the PV are connected in parallel is supported. 3) One of the PV modules has permanently dropped from ~30-35v output to 13v, regardless of test or operating conditions. 4) When the failed panel is removed from the array, the three remaining panels come back to normal voltage, but after approx 15 minutes drop down to around 13v on the Blue Sky display, even though the individual output from each panel when unhooked and tested in full sun show about 35v. 5) After turning the system off and on again a few minutes later the normal voltages return but drop again in about 15 min. The failed panel stays at 13v, does not recover. Speculative long-distance diagnostics are always challenging. First: The PV module that shows 13 volts open-circuit voltage under all test conditions (hot, cold, open-circuit, etc.) has experienced permanent failure (short) of two of the three bypass diodes. Explanation: Bypass diodes typically shunt 1/3 or 1/4 of the cells in a module. The specified PV have 72 cells, so there's one bypass diode across each of 24 cells in this particular PV module. When a diode fails, it shorts the portion of the module across which it's connected, and the PV voltage drops accordingly. Next: Ron Young (original poster), stated the voltage of the remaining modules drops after 15 minutes use when the system is turned off, then back on again. Ron didn't specify the magnitude of this drop, so I can only guess whether this is the normal Voc to Vmpp decrease .. or he means this too is a decrease from nominal Voc to 13V or some similar voltage. Presuming the latter, this would indicate the heating of the PV is causing one or more bypass diodes in one or more of the remaining modules to fail short intermittently. To that, and to isolate the affected module, the PV must be disconnected from each other, and each module tested separately under the conditions under which the failures were noted. As a point of clarification, and since the four PV in this array are parallel connected, there is no appreciable current being forced through any one module by any of the other modules when all are operating normally. In the event of one or more shorted bypass diodes in a module, then all current from the remaining PV in the array will flow through the shorted diodes in the faulty PV. Defects in the cell buss structure or connections could come into play in a parallel array by causing hot-spot heating, along with possible current being forced through the PV due to the excessive voltage drop caused by that resistance. This could also cause the bypass diodes in the affected PV to be forced into the conductive mode. If this happened often enough, could in turn lead to eventual failure of the diodes, as many bypass diodes relied on convective and radiant cooling within the junction box - and this doesn't work very well. I've got thermograph images of junction boxes with bypass diodes conducting, and the measured temperatures are impressively high, and very eye-opening. That said... The only means to accurately diagnose the PV would be to completely disconnect them, face them into the sun, let them heat up, then at an absolute minimum, take Voc and Isc measurements for each module. It would also be highly recommended that the Isc measurement be taken for a period of several minutes, because internal heating (and subsequent failure of bad connections) may not show up until the connection(s) gets hot enough to fail. Also ... To correct an earlier statement made within this thread, where a poster said diodes usually fail open ... this is incorrect. Diodes fail short. The only time they fail open is when they are mechanically faulty, which then causes the conductive path to open (rare), or when they are totally destroyed -- and thus obviously open. Can a diode fault be intermittent? Yes. Though not common, it is always mechanical in nature caused by thermally-related expansion/contraction. Otherwise, short is the failure mode in diodes. Conclusions: One of the four PV has suffered permanent failure in two of the three bypass diodes. Symptoms reported by Ron Young (the original poster) indicate one or more of the remaining PV are experiencing intermittent thermally-related short-circuit failures in the bypass
Re: [RE-wrenches] Outback wave form
Wrenches, While the addition of a capacitor may resolve issues associated with various inverter/appliance/motor combinations, please make sure the capacitor(s) get switched OUT of the circuit (disconnected) when the load itself is disconnected. Failure to do so could under some circumstances cause the inverter control-loop circuitry to go unstable, leading to unpredictable inverter operation, and possible damage/failure in the power system. Disconnecting the capacitor with the load alleviate this possibility. Regards to all... Dan Lepinski --- On Wed, 4/17/13, Larry Crutcher, Starlight Solar Power Systems la...@starlightsolar.com wrote: From: Larry Crutcher, Starlight Solar Power Systems la...@starlightsolar.com Subject: Re: [RE-wrenches] Outback wave form To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Wednesday, April 17, 2013, 2:09 PM We experience issues like this from time to time. PF seems to be the culprit. Have you measured it or looked at the waveform yet? How an inverter deals with PF seems to vary broadly. For example, the Splendide XC2100 washer/dryer will not work on a Magnum Energy and a few other sine wave inverters. However, it will run on a low cost GoPower or Samlex sine wave inverter. Below is a scope trace of voltage/current of the Magnum inverter Splendide washer. Upper trace is voltage By adding a 50uF run capacitor inline, it somewhat tames the current phase and the sine wave so the Magnum can operate the washer. (Special thanks to Al for the discovery and photos) Larry Crutcher Starlight Solar Power Systems On Apr 16, 2013, at 9:46 AM, All Solar allso...@scswifi.net wrote: Have a client with a new coffee maker that will not run from their new dual outback setup. Has anyone heard of this lately. We have had no problems with appliances and sine wave inverters. What to look for? Sent from Jeremy's IPhone. Sorry for typos and shorthand! ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org -Inline Attachment Follows- ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Cable tray
Conductors rated for 1000V and the same power you have in mind for the 600V conductors (hence lower current) can indeed use smaller wire, thus potentially saving on that aspect of the cost, and possibly making it lower in cost for a given system than the lower-voltage higher current counterpart. If the European hardware you bought is fully certified to the required UL Standards for use in the USA, then product size is simply a matter of design differences. Could also be product volume since they are way ahead of us in the 1000V category. Issues we as manufacturers in America face when trying to compete with firms in other countries are: 1) numerous additional costs related to things like Workman's Comp insurance, social security (for every dollar you have withheld, the employer matches it), now mandatory health insurance for some (depending on company size), and so forth. 2) Strict environmental regulations that foreign companies may or may not have. Even if they DO, we often find enforcement of those rules to be very lax, especially in Asia. 3) Cost of living, thus higher wages in the USA. .. to name a few. Ends up being higher-cost products. Dan --- On Mon, 4/1/13, Chris Mason cometenergysyst...@gmail.com wrote: From: Chris Mason cometenergysyst...@gmail.com Subject: Re: [RE-wrenches] Cable tray To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Monday, April 1, 2013, 9:23 AM With regards to 600V costs Vs 1000V costs, once 1000V equipment becomes the norm, it is likely not to cost appreciably more, and the lower cost of copper will offset any increase. I bought 1000V SolarBos combiners which are huge, too big to use on my installation, so I bought the same item from the UK, which are tiny and easy to install, and half the cost. Something is wrong with the US approach to 100V equipment and switchgear in general. Why is the european equipment so much smaller for the same switching current. ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Cable tray
Hello Chris, From a manufacturer's perspective .. you're incorrect on all assumptions. (Sorry.) It costs more to make higher-voltage anythings. Higher voltage means: Clearance / creepage distances are larger (thus bigger parts or products). Insulation must be thicker (or have a higher dielectric rating). This results in more rigorous (consequently more expensive) UL testing. Etc. All adds up. Dan --- On Sun, 3/31/13, Chris Mason cometenergysyst...@gmail.com wrote: From: Chris Mason cometenergysyst...@gmail.com Subject: Re: [RE-wrenches] Cable tray To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Sunday, March 31, 2013, 8:21 AM As we see more 1000V installations, chances are that 600V rated equipment will find its way into installations it is not rated for. To avoid problems and so we don't need two SKUs and lots more inventory, the manufacturers need to move all their product to 1000V ratings. I suspect it does not cost more to make 1000V wire than 600V, similarly disconnects, fuses, fuse holders and connectors. ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Cable tray
John, My reply didn't deal with anything except specific hardware (per Chris' mention in his original post), his musings that he suspects it does not cost more to make that leap, and the actual impact on cost for migrating that hardware from 600Vdc to 1000Vdc. Nothing was mentioned either by Chris or by me related to control electronics, power ratings, or power loss. To Chris' statement: BEGIN QUOTE: I suspect it does not cost more to make 1000V wire than 600V, similarly disconnects, fuses, fuse holders and connectors. END QUOTE. All things being equal: 1000V wire in the same gauge as 600V wire will be more expensive than the 600V wire. If you wish to downsize the conductor, the cost of the metal is likely more expensive than the insulation, and this is a potential win .. but conductor size wasn't mentioned. 1000V disconnects for a given current are going to be more expensive than 600V disconnects. 1000V rated fuses are going to be more expensive than 600V for a given current. 1000V fuse holders require larger spacings than 600V, so they too are more money. 1000V connectors require larger creepage and clearances than do 600V parts. This means they're larger for a given number of contacts and current, thus more $$$ -- even if just slightly more. Still more. This is not to say migrating to 1000V won't happen. It will, and it is. Yes, it's more common in Europe. Sometimes the USA doesn't lead, but follows. This is one of those instances. And to your point: John Berdner Wrote: Although the spacing between the high voltage dc components increases, the power of the device also increases and the losses decrease. Referencing I^2 R loss .. yes. Passive resistive devices at a higher voltage and lower current do have less loss than their lower-voltage cousins, (again, all things being equal, but that doesn't mean they're less expensive than their lower-voltage counterpart. It's simply not possible to make a blanket statement and have it cover everything correctly. And to your additional point: Small gauge PV wire is already available from multiple sources with 1000 and 2000 V ratings for a small premium over 600 V wire. ... for a small premium over 600V wire. You admit the wire is more expensive (even if at present). Still, it's more $. Will it stay that way? Likely not, but for NOW .. it's more expensive. Now then .. taking your comment in context: BEGIN QUOTE: Example: The control electronics and all ac output circuitry remain the same. Although the spacing between the high voltage dc components increases, the power of the device also increases and the losses decrease. The result is that the product might be a little larger but its power rating will be higher and it will likely be more efficient. This infers reference to the efficiency of switching electronics. If so, your statement is incorrect. Let's consider the solid state switches in an inverter, whether they be MOSFETs, IGBTs, GaN, etc. With the devices presently on the market, switching loss goes UP as the voltage increases. This will likely change at some future point with new product discoveries, but for now .. given the parts we have to work with, switching losses are greater in the higher voltage parts. I know this flies in the face of common sense to non-engineers, but it's fact. If you wish an alternate resource of verification on this, I suggest you check with anyone else with considerable expertise in the design of switchmode power supplies. If my 41 years as a design engineer isn't adequate here, boB and/or Robin at at Midnight Solar would be an excellent starting point. I can point you toward a number of others who are equally qualified. Our industry (and even perhaps the Wrench board) has others as well. Ultimately .. will higher voltage systems be lower cost per watt overall? This remains to be seen. My instincts say it will --- in some circumstances. An advantage the increased voltage offers (beyond potentially less power loss in conductors), is the ability to create inverters for 277/480 and beyond. This helps by eliminating a transformer, which IS an efficiency loss and added cost element. Will 1000Vdc be a win for [say] 120V/240V installations. Likely not. As John did point out .. the entire system must be considered. That goes without saying. Whether higher voltage is a win or not depends on the system. It may be in some cases, and not in others. Chris mentioned only specific aspects of the BOS hardware -- which I addressed. Regards to all, Dan Lepinski Sr. Engineer Exeltech / Exeltech Solar Products --- On Sun, 3/31/13, John Berdner john.berd...@solaredge.com wrote: From: John Berdner john.berd...@solaredge.com Subject: Re: [RE-wrenches] Cable tray To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Sunday, March 31, 2013, 1:08 PM Dan: I have to disagree with your statement regarding costs and voltage.While clearance and creepage distances
Re: [RE-wrenches] P1 micro performance
Marco .. and Wrenches .. I'm going to take a run at this -- just once. First ... Without proper and *accurate* data acquisition equipment, there's no way to know what the actual available PV wattage is compared to the inverter's output wattage when its output is being *LIMITED*. This limiting action occurs in an inverter when there's more available power at the input than the inverter can produce at its output. Subsequently, you don't know how much potential energy wasn't harvested. Now then ... Let's say the inverter is producing 216 watts, and the PV *could* produce 227.3 watts at max power point under those specific conditions if every PV-generated milliwatt were used. Next, and presuming the inverter is 95% efficient, that's a limited loss of ONE WATT. 227.3 x 95% = 215.94 watts (OK, so I fudged 0.06 watt). Under what conditions (and since you're in Hawaii, I'll use 70F) would this occur, and with what size PV? I went to my magic spreadsheet and grabbed the first 270-watt-rated PV I could find. NESL DJ-270P,. YOU think it's producing 270 watts. It's not. At 77F (25C), and under the conditions of 100% irradiance, perfectly orthogonal to the sun at mid-day, light wind, that particular PV will produce 227 watts +/- its tolerance. (Let's say the tolerance is dead on.) Now, consider the benefit of increased energy output due to more rapid output wattage rise experienced during early morning, and the higher output later in the afternoon, AS WELL AS the increased power output realized during periods of less than 100% irradiance one derives from using larger PV compared to PV you might consider perfectly matched to the inverter. ALL of this adds up to more kilowatt-hours produced annually than had the inverter been connected to your perfect PV that doesn't produce enough wattage to have the inverter begin limiting its output. The shoulders of the output wattage curve are steeper than with lower-wattage PV. Granted you *could* connect the inverter to [say] a 450 watt PV module, and that would truly be a waste of the PV wattage. There *is* a broad sweet spot for AC Module inverters and microinverters alike, and it's actually on the higher side of the PV's rated output wattage versus the inverter's wattage rating. So, can you over-do it? Sure. But there IS an overall kilowatt-hours-produced benefit for *modest* over-sizing the PV. What I *can't* answer is the long-term effect this may have on the overall life of the inverter. THAT depends on various intricate design considerations that went into creating the inverter in the first place. This isn't an Enphase issue, nor are they trying to mislead you on this topic. It's an industry-wide issue. Wrenches face it every time you designed a string system, especially those being installed in regions with wide temperature swings. Trying to explain in depth the how and why slightly larger PV is of benefit to a customer is like trying to explain photovoltaic equipment to the general public. As a competitor to Enphase .. I'm not coming to their defense. However, what Nick said (below) IS fact. Whether you elect to believe this or not is up to you. Regards to all, Dan Lepinski, Senior Engineer Exeltech / Exeltech Solar Products With 41 years experience as a design engineer in solar energy. --- On Sat, 3/23/13, Marco Mangelsdorf ma...@pvthawaii.com wrote: From: Marco Mangelsdorf ma...@pvthawaii.com Subject: [RE-wrenches] P1 micro performance To: 'RE-wrenches' re-wrenches@lists.re-wrenches.org Date: Saturday, March 23, 2013, 4:04 AM Yes, I know that that screen shot was only a moment in time. Here it’s only March and clipping is already taking place. Imagine what kind of clipping is going to take place at higher irradiance levels later in the year. Yes, the monitoring program cannot as of now quantify what kind of harvesting losses would take place over time compared to an identical array using Enphase micros. But the principle remains unchallengeable: not allowing for maximum kWh harvesting is plain and simple NOT the best design strategy. “Some clipping is good”? You’ve got to be joking. Not being able to harvest usable solar energy is good? What kind of optimal design philosophy is that? As module outputs have been going up, Enphase has a vested interest in continuing to move product with little regard for the harvestable energy being essentially lost. Using larger micros that reduce or eliminate that clipping is prima facie a good thing if one cares about maximizing kWh harvest. As more micro products come on the product with higher outputs than the venerable and solid M215, Enphase risks being left behind and losing market share. I for one find that “white paper” overly self-serving. marco From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Nick Soleil Sent: Thursday, March 21, 2013 8:04 PM To: RE-wrenches Subject: Re: [RE-wrenches] P1 micro
Re: [RE-wrenches] P1 micro performance
Wrenches, I'm probably a lone voice on this .. and not intending to get overly picky. Could we call power limiting what it is .. limiting, and not clipping? Clipping implies distortion, which isn't the case here. Limiting is just that. The inverter output is limited to some maximum value -- not clipped. The output power curve flattens when integrated over time, but this still isn't distortion in the waveform. It's simply a point in the output where the derivative is zero. Not increasing, not decreasing. Just .. zero. No additional increase in the output for an increase in available energy at the input. Think governor on an engine Thanks. Dan Lepinski, Sr. Engineer Exeltech / Exeltech Solar Products --- On Thu, 3/21/13, David Brearley david.brear...@solarprofessional.com wrote: From: David Brearley david.brear...@solarprofessional.com Subject: Re: [RE-wrenches] P1 micro performance To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Thursday, March 21, 2013, 11:37 PM Thanks for sharing the screen capture, Marco. Interesting issues to think about here. This is actually prime clipping season in many places (not sure about Hawaii) due to the cool weather. While there are more sun-hours in the summer, the cell temperatures are often high enough that you won't tend to see rated power out of the modules. While I'm not running performance models for work, the people who do are routinely increasing dc-to-ac ratios, often as high as 1.4-to-1. Having said that, most inverters aren't installed on a roof. (Not yet anyway.) I'd probably lean to a more conservative sizing ratio for micros. While I can imagine some scenarios where I'd be comfortable with a 215 W micro on a 265 W module—like a flat roof install in Vermont, which reportedly doesn't see 1,000 W/m^2 very often—I wouldn't try that here in Texas. ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] DC circuit breakers in parallel
William and all, Our larger UL-certified inverter systems at Exeltech are routinely built with multiple individual breakers with the handles pinned together to create a higher-amperage device. To William's point, and by way of example, it's common for us to have three 100-amp breakers ganged together with hardware designed for that purpose (typically a knurled pin and an outer sleeve) to create [in effect] a 300 amp breaker. It takes special hardware to ensure absolutely free movement of the breaker handles and avoid interference with the mechanical aspects during a trip action that may otherwise prevent the breaker from opening properly during an actual over-current event. While there are *some* breakers that are internally ganged, all such units I've ever seen have a double-wide body, but just one handle. If there are breakers with more than two that are thus internally ganged .. I've not seen them. (Not saying they don't exist, just that I personally haven't seen any.) For the past 12 years, I've been in charge of the UL program at Exeltech. As long as the breakers we use are NRTL Recognized, with ratings that are appropriate for the circuit voltage and current, our equipment is accepted and certified by UL (and the other NRTLs). This includes breaker stacks we essentially create from individual breakers in parallel. We have literally hundreds of models of inverters built this way, all UL Listed. As a point of personal comment, anyone ganging multiple breakers together in this manner should also utilize the connection concept commonly used for multiple parallel batteries -- make connections at the opposite diagonal corners to help ensure equal current flow in all of the breakers. Also ...for anyone not familiar with NRTL, it means Nationally Recognized Testing Laboratory, such as UL, Intertek, CSA, etc.. Larry's application was mobile, so in the end, the NEC didn't apply in his situation, but I credit him for asking as part of his due-diligence to help ensure best practices were employed in his project. This has been a very interesting thread where the NEC *would* be a consideration. Regards to all, Dan Lepinski Senior Engineer (41 years in the RE industry and it's still fun) --- On Wed, 2/27/13, William Miller will...@millersolar.com wrote: From: William Miller will...@millersolar.com Subject: Re: [RE-wrenches] DC circuit breakers in parallel To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Wednesday, February 27, 2013, 11:56 PM Larry: I was tempted to advise against this. I see a similar concept with people trying to parallel PV feeds and then putting two charge controllers at the destination. Not good. However, I see many 200 amp main breakers that are 4 100 amp breakers ganged, with two for each phase. I can not presume to know about the requirements of internal ganging. William Miller At 08:06 AM 2/27/2013, you wrote: Hello Wrenches, I am installing a Classic 150 controller in an RV with potential 95 amps output at 12 volts. The customer has a Midnite DIN box and wants me to use it for the controller output. I am out of 150VDC breakers but I have two 60 amp breakers. Is it safe and reliable to use the 2 breakers in parallel for this purpose? I can pin the two handles together. There will be other circuit protection at the battery. Thank you, Larry Crutcher Starlight Solar Power Systems ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] DC circuit breakers in parallel
Use a good pin to lock them together. Make sure they can't disengage (lock-tite the hardware, etc.) and you're good to go. Stay warm out there (ha!). Dan --- On Wed, 2/27/13, Larry Crutcher, Starlight Solar Power Systems la...@starlightsolar.com wrote: From: Larry Crutcher, Starlight Solar Power Systems la...@starlightsolar.com Subject: Re: [RE-wrenches] DC circuit breakers in parallel To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Wednesday, February 27, 2013, 2:17 PM Hi Dan, NEC does not apply to mobile systems. Thus the reason for asking about safe and reliable instead of code compliant. Thank you, Larry CrutcherStarlight Solar Power Systems On Feb 27, 2013, at 11:56 AM, d...@foxfire-energy.com d...@foxfire-energy.com wrote: Check out NEC 240.8 db Dan Brown Foxfire Energy Corp. Renewable Energy Systems (802)-483-2564 www.Foxfire-Energy.com NABCEP #092907-44 -Inline Attachment Follows- ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] GEC for Micro-Inverters and ACPV Modules
Hello Mark (and all), Exeltech AC Module inverters do not have an external ground connection because they are certified to UL1741 as grounded through the utility ground. Also, and because all DC wiring is internal to the inverter, there is no requirement for DC ground-fault or arc-fault circuitry in our inverters. Installers don't need to attach a ground conductor to our inverters. That step has already been done internally for you. To attain this certification, and as part of the certification to UL1741, our inverters had to conduct 40 amps through the chassis and inverter wiring without damage or destruction to the conductors and connectors. Dan Lepinski, Senior Engineer Exeltech / Exeltech Solar Products --- On Mon, 1/14/13, Mark Frye ma...@berkeleysolar.com wrote: From: Mark Frye ma...@berkeleysolar.com Subject: [RE-wrenches] GEC for Micro-Inverters and ACPV Modules To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Monday, January 14, 2013, 5:31 PM Does anyone have the latest on the GEC for micro-inverters/ACPV issue? I know it is still in NEC 2008 and I believe 2011 with plans to address it in 2014. I am specifically interested in the issue of GEC means continues (irreversible splices) and the whole business of the DC side of these devices constituting a separately derived system. Enphase technical support is fine if the micro inverter chasis is bonded to a EGC only, but they leave the lug on the chasis if you want/need to build a GEC. SolarBridge (pre-assembled micro-inverter) seems to be devoid of a chasis lug and therefore by extension does not/can not had a GEC in the system. Exeltech (integrated micro-inverter aka. ACPV) does not seem to have a lug on its chasis. Has the industry pretty much moved to not requiring a GEC for these devices and if so, how are the AHJ taking it? Thanks, Mark Frye Berkeley Solar Electric Systems ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] roof rakes
I lived off-grid for eight years in the Wisconsin north woods. Snow accumulating on PV and hot water collectors was often a problem. I used a lightweight plastic-framed cloth floor broom. Had a threaded handle screwed into the broom head. The broom head threads were the same size as handles for paint roller extensions, which come in short to very long lengths. Bought extensions to reach the highest point. Extensions are made in both plastic and wood. I used plastic for the light weight, the kind that had metal caps for the threads. Anything else tended to strip out over time. Brooms are also available in various sizes as needed. Worked perfectly (except on ice from ice storms). Low-cost, and readily available year-round. Dan --- On Sun, 12/2/12, Jesse Dahl dahlso...@gmail.com wrote: From: Jesse Dahl dahlso...@gmail.com Subject: Re: [RE-wrenches] roof rakes To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Sunday, December 2, 2012, 3:53 PM I made mine from an old shovel handle and a chunk of wood wrapped in carpet. It was basically free and works for clearing my truck as well. Jesse Sent from my iPhone On Dec 2, 2012, at 3:49 PM, Stephen Kane kanesteph...@gmail.com wrote: Hey Nicholas, I’ve always liked the Sno Knife (American made). It is used kind of like a spatula: http://sno-knife.com/ I also like all plastic roof rakes for a pulling motion from the ground: http://www.suncast.com/productdisplay.aspx?id=134pid=46 Best, Stephen KaneKane Solar720.365.3994Lyons, CO From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Nik Ponzio Sent: Sunday, December 02, 2012 1:46 PM To: RE-wrenches Subject: [RE-wrenches] roof rakes Does anyone have a particular roof rake to recommend for clearing snow off low roofs and ground-mount arrays? Plastic, poly, squeegee So many choices! -- Nicholas Ponzio Building Energy 1570 South Brownell Road Williston, VT 05495 802-859-3384 ext.15 (office) 802-658-3982 (fax) 802-318-4783 (cell) http://www.BuildingEnergyVT.com ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Still walking it back
Hi Larry and Wrenches, Battery resistance is a matter of semantics depending on the direction of the current flow. For charging, the applicable term is acceptance. In this context, a fully discharged battery, when connected to a source of charging current, allows for a rate of current flow generally limited only by the charging source. Hence, the opposition to current flow when charging a very discharged battery is quite low. If one were to connect a discharged battery to a source of extremely high current capability (let's say in the many thousands of amps), a fully discharged battery would allow a current flow limited only by its own internal resistance. This can (and does) lead to spectacularly high currents, and unpleasant consequences. Conversely, it's the battery's internal resistance that in turn limits the current flow when connected to a load and delivering current. When fully charged, internal resistance is quite low, and increases as the charge level decreases. So, to be as correct as possible, we need view acceptance and internal resistance essentially as reciprocals of each other. Their applicability in context will be determined by the direction of current flow into or out of the battery. Keep up the good work all Dan Lepinski, Senior Engineer Exeltech Solar --- On Fri, 11/2/12, Larry Crutcher, Starlight Solar Power Systems la...@starlightsolar.com wrote: From: Larry Crutcher, Starlight Solar Power Systems la...@starlightsolar.com Subject: Re: [RE-wrenches] Still walking it back To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Friday, November 2, 2012, 11:35 AM Dan is correct if the discussion is about the open circuit test of a charged battery: resistance is lower than when discharged. However, the resistance I was describing to Mick was the effect of a battery under charge. The resistance to current flow increases because the electrochemical process slows down as active material is converted back to it's original state. I believe this is what Dan meant by equilibrium, PbSO4 is converted to PbO2, Pb and H2SO4 increasing specific gravity, reducing current flow. A common question I am asked is why can't I force my charger (PV solar or otherwise) to put out full power? The reason is the battery simply can't absorb any more current as described above. Larry Crutcher Starlight Solar Power Systems On Nov 2, 2012, at 8:41 AM, Mick Abraham wrote: Hi, Mechanix~ I'm sorry to add more noise to the List but I sort of mis-spoke again. Dan Lepinski @ Exeltech sent a mail to me Off List; below I am posting the part of his mail which addresses my latest faux pas: + As battery state of charge increases (toward 100%), the internal resistance actually goes *down* -- which is why you can get a very high short-circuit current from a fully charged battery .. and a much less current from a nearly dead one. What is happening instead is a voltage equilibrium -- that of the battery becoming more equal with the voltage of the charging source. This is what reduces the charge current flowing from a constant-voltage source into the battery. Think of it this way: If you're adding air to a car tire, and have a compressor that produces a maximum of 35 psi, as the tire pressure approaches 35 psi, the air flow from the compressor to the tire will slow, and then eventually stop when the two pressures become equal. ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] AC Modules ready for primetime?
I'd like to correct an error in Jim's statement below related to how we at Exeltech handle warranty. If an AC Module inverter should fail, the entire module does not need to be sent back for warranty -- just the inverter itself. In our case, this involves removing four small screws to separate the inverter from the base. The lid (or top of the enclosure) is the heat sink of the inverter. The base stays attached to the PV. There's no wiring involved. It's all internal, and you don't have to do anything except remove the old inverter from the base and plug in the new one. Once you access the back of the PV, total time to effect the swap is typically about 1 minute. Dan Lepinski, Senior Engineer Exeltech Solar --- On Wed, 10/31/12, Solarguy nt...@1scom.net wrote: From: Solarguy nt...@1scom.net Subject: Re: [RE-wrenches] AC Modules ready for primetime? To: 'RE-wrenches' re-wrenches@lists.re-wrenches.org Date: Wednesday, October 31, 2012, 9:05 AM Another question to consider when it comes to ACPV warranty replacement is, do you have to send the entire module back for repair if there’s a warranty claim on the inverter. Solar Bridge Exeltech both say yes. All things equal, Solar Bridge still has DC apparatus exposed but not Exeltech. It would be nice to just be able to drill out the pop rivets and unplug the SB unit return for repair. And yes, I’m kinda biased toward Exeltech but they have been building inverters for 20+ years. Jim DuncanNorth Texas Renewable Energy Incwww.ntrei.com NABCEP PV 031310-57tecl-27398nt...@1scom.net 817.917.0527 From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of William Dorsett Sent: Wednesday, October 31, 2012 12:14 AM To: 'RE-wrenches' Subject: Re: [RE-wrenches] AC Modules ready for primetime? Kirk, the BenQ modules use SolarBridge inverters. One of the questions to ask with ACPV is who backs the warranty on the inverter. According to SolarBridge’s website, the module manufacturer warranty’s the combination. This is fine as long as the mfg stays afloat but in this time with such major players as Sharp and BP backing out, who do you turn to if your inverter has a problem? As Bill said Exeltech is in this too, and warranty’s their own, so is one step less removed. One of the things we’ve gathered is that Enphase, with an installed base of something over a million, is having some problems with its first version, 190. Is that a problem inherent in the components chosen in its design or something as simple as insufficient potting? It is fairly low percentage, but it also hasn’t been 25 years. And how does that balance with the installed base of any of the other microinverter/ACPV manufacturers? It seems that the temperature at which micros are required to live is the main advantage of remote string inverters. They can be down in the shade with free air moving around them. On the other end of that trend are the ACPV which might have very little room between them and the module backing. There might be several practical actions like mounting the modules with the inverter on the down side so the air flow is cooler (a little like putting the pump or fan on the cool input side of a thermal collector), or spacing the array higher off the roof to allow more air flow. I do agree with Bill that this is the direction the industry is heading and very quickly. Bill DorsettSunwrightsManhattan, KS From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Bill Loesch Sent: Tuesday, October 30, 2012 11:43 AM To: RE-wrenches Subject: Re: [RE-wrenches] AC Modules ready for primetime? Hi Nik, As of SPI 2012, Solar Bridge advertized seven module manufacturers using their product. Remember Exeltech, manufacturer of exemplary sine wave inverters, is also a player in this ACPV market, undoubtedly other players, too. IMHO, ACPV is the route that the industry will _eventually_ follow. Bill LoeschSolar 1 - Saint Louis Solar314 631 1094On 30-Oct-12 10:13 AM, Nik Ponzio wrote:I have a prospective customer requesting AC modules for a commercial job. What is currently available? Thanks in advance. Nik ___List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings:http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette:www.re-wrenches.org/etiquette.htm Check out participant bios:www.members.re-wrenches.org No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2221 / Virus Database: 2441/5363 - Release Date: 10/30/12 No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2221 / Virus Database: 2441/5363 - Release Date: 10/30/12 -Inline Attachment Follows
Re: [RE-wrenches] AC Modules ready for primetime?
Hello David, Our inverters are a *true* AC Module, not just a micro-inverter that's been attached to the PV frame or other structure. They replace the junction box on PV, and must be installed by a PV manufacturer, distributor, or OEM that are certified to the appropriate UL Standards for that process. Our AC Modules are not designed for field/site installation to PV. The advantages to this: We're exempt from DC-side ground-fault and arc-fault because all DC conductors are internal to our inverter, and are all less than 80Vdc. Being mounted directly to the PV eliminates the j-box, diodes, high-voltage DC conductors, and expensive DC connectors and their associated hassles. This also reduces the product cost and decreases the system installation time. You're also assured of a perfect match of our inverter to the PV. For notes - our AC Module inverters are made in Fort Worth, Texas. Dan Lepinski, Senior Engineer Exeltech Solar --- On Wed, 10/31/12, David Katz dk...@aeesolar.com wrote: From: David Katz dk...@aeesolar.com Subject: Re: [RE-wrenches] AC Modules ready for primetime? To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Wednesday, October 31, 2012, 10:39 AM Dan Lapinski, Does Exeltech make a microinverter that can be site-installed? David Katz Sent from my HTC smartphone on the Now Network from Sprint! - Reply message - From: Exeltech exelt...@yahoo.com To: RE-wrenches re-wrenches@lists.re-wrenches.org Subject: [RE-wrenches] AC Modules ready for primetime? Date: Wed, Oct 31, 2012 7:26 am I'd like to correct an error in Jim's statement below related to how we at Exeltech handle warranty. If an AC Module inverter should fail, the entire module does not need to be sent back for warranty -- just the inverter itself. In our case, this involves removing four small screws to separate the inverter from the base. The lid (or top of the enclosure) is the heat sink of the inverter. The base stays attached to the PV. There's no wiring involved. It's all internal, and you don't have to do anything except remove the old inverter from the base and plug in the new one. Once you access the back of the PV, total time to effect the swap is typically about 1 minute. Dan Lepinski, Senior Engineer Exeltech Solar --- On Wed, 10/31/12, Solarguy nt...@1scom.net wrote: From: Solarguy nt...@1scom.net Subject: Re: [RE-wrenches] AC Modules ready for primetime? To: 'RE-wrenches' re-wrenches@lists.re-wrenches.org Date: Wednesday, October 31, 2012, 9:05 AM Another question to consider when it comes to ACPV warranty replacement is, do you have to send the entire module back for repair if there’s a warranty claim on the inverter. Solar Bridge Exeltech both say yes. All things equal, Solar Bridge still has DC apparatus exposed but not Exeltech. It would be nice to just be able to drill out the pop rivets and unplug the SB unit return for repair. And yes, I’m kinda biased toward Exeltech but they have been building inverters for 20+ years. Jim Duncan North Texas Renewable Energy Inc www.ntrei.com NABCEP PV 031310-57 TECL-27398 nt...@1scom.net 817.917.0527 From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of William Dorsett Sent: Wednesday, October 31, 2012 12:14 AM To: 'RE-wrenches' Subject: Re: [RE-wrenches] AC Modules ready for primetime? Kirk, the BenQ modules use SolarBridge inverters. One of the questions to ask with ACPV is who backs the warranty on the inverter. According to SolarBridge’s website, the module manufacturer warranty’s the combination. This is fine as long as the mfg stays afloat but in this time with such major players as Sharp and BP backing out, who do you turn to if your inverter has a problem? As Bill said Exeltech is in this too, and warranty’s their own, so is one step less removed. One of the things we’ve gathered is that Enphase, with an installed base of something over a million, is having some problems with its first version, 190. Is that a problem inherent in the components chosen in its design or something as simple as insufficient potting? It is fairly low percentage, but it also hasn’t been 25 years. And how does that balance with the installed base of any of the other microinverter/ACPV manufacturers? It seems that the temperature at which micros are required to live is the main advantage of remote string inverters. They can be down in the shade with free air moving around them. On the other end of that trend are the ACPV which might have very little room between them and the module backing. There might be several practical actions like mounting the modules with the inverter on the down side so the air flow is cooler (a little like putting the pump or fan on the cool input side of a thermal collector), or spacing the array higher off the roof to allow more air flow. I do agree
Re: [RE-wrenches] AC Modules ready for primetime?
Hello Kirk, Our PVAC Modules are certified to UL and other applicable Standards on: Helios PV, Milwaukee, Wisc ( http://www.heliossolarworks.com/ ) PV made in Milwaukee + our AC Module inverters made in Fort Worth yields a 100% Made in America product. NB Solar (made by Sun Earth Solar), China In the PV business for 44 years. ( http://www.nbsolar.com/ ) Top Sun (Korea) Vertically integrated PV manufacturer of ingots, wafers, cells, and PV modules. ( http://www.topsun.kr/english/main/main.htm ) Distributed by Solarbine, with offices/warehouse facilities in Pennsylvania, Texas, and Southern California. ( http://www.solarbine.net/ ) More PV manufacturers are working their way through in UL certification at this time, but non-disclosure agreements won't allow discussion yet. Dan Lepinski, Senior Engineer Exeltech Solar --- On Wed, 10/31/12, Kirk Herander k...@vtsolar.com wrote: From: Kirk Herander k...@vtsolar.com Subject: Re: [RE-wrenches] AC Modules ready for primetime? To: 'RE-wrenches' re-wrenches@lists.re-wrenches.org Date: Wednesday, October 31, 2012, 1:53 PM Dan, What panel OEM’s are using your AC modules? Kirk HeranderVT Solar, LLCdba Vermont Solar EngineeringNABCEPTM Certified Inaugural CertificantNYSERDA-eligible InstallerVT RE Incentive Program Partner802.863.1202 From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Exeltech Sent: Wednesday, October 31, 2012 12:05 PM To: RE-wrenches Subject: Re: [RE-wrenches] AC Modules ready for primetime? Hello David, Our inverters are a *true* AC Module, not just a micro-inverter that's been attached to the PV frame or other structure. They replace the junction box on PV, and must be installed by a PV manufacturer, distributor, or OEM that are certified to the appropriate UL Standards for that process. Our AC Modules are not designed for field/site installation to PV. The advantages to this: We're exempt from DC-side ground-fault and arc-fault because all DC conductors are internal to our inverter, and are all less than 80Vdc. Being mounted directly to the PV eliminates the j-box, diodes, high-voltage DC conductors, and expensive DC connectors and their associated hassles. This also reduces the product cost and decreases the system installation time. You're also assured of a perfect match of our inverter to the PV. For notes - our AC Module inverters are made in Fort Worth, Texas. Dan Lepinski, Senior Engineer Exeltech Solar --- On Wed, 10/31/12, David Katz dk...@aeesolar.com wrote: From: David Katz dk...@aeesolar.com Subject: Re: [RE-wrenches] AC Modules ready for primetime? To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Wednesday, October 31, 2012, 10:39 AMDan Lapinski, Does Exeltech make a microinverter that can be site-installed? David Katz Sent from my HTC smartphone on the Now Network from Sprint! - Reply message - From: Exeltech exelt...@yahoo.com To: RE-wrenches re-wrenches@lists.re-wrenches.org Subject: [RE-wrenches] AC Modules ready for primetime? Date: Wed, Oct 31, 2012 7:26 am I'd like to correct an error in Jim's statement below related to how we at Exeltech handle warranty. If an AC Module inverter should fail, the entire module does not need to be sent back for warranty -- just the inverter itself. In our case, this involves removing four small screws to separate the inverter from the base. The lid (or top of the enclosure) is the heat sink of the inverter. The base stays attached to the PV. There's no wiring involved. It's all internal, and you don't have to do anything except remove the old inverter from the base and plug in the new one. Once you access the back of the PV, total time to effect the swap is typically about 1 minute. Dan Lepinski, Senior Engineer Exeltech Solar --- On Wed, 10/31/12, Solarguy nt...@1scom.net wrote: From: Solarguy nt...@1scom.net Subject: Re: [RE-wrenches] AC Modules ready for primetime? To: 'RE-wrenches' re-wrenches@lists.re-wrenches.org Date: Wednesday, October 31, 2012, 9:05 AMAnother question to consider when it comes to ACPV warranty replacement is, do you have to send the entire module back for repair if there’s a warranty claim on the inverter. Solar Bridge Exeltech both say yes. All things equal, Solar Bridge still has DC apparatus exposed but not Exeltech. It would be nice to just be able to drill out the pop rivets and unplug the SB unit return for repair. And yes, I’m kinda biased toward Exeltech but they have been building inverters for 20+ years. Jim DuncanNorth Texas Renewable Energy Incwww.ntrei.com NABCEP PV 031310-57tecl-27398nt...@1scom.net 817.917.0527 From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of William Dorsett Sent: Wednesday, October 31, 2012 12:14 AM To: 'RE-wrenches' Subject: Re: [RE-wrenches] AC Modules ready for primetime? Kirk, the BenQ modules use SolarBridge inverters. One
Re: [RE-wrenches] AC Modules ready for primetime?
Jason, You're describing our Home Run cable and the connectors for the AC Modules. Replacements are easy. The inverter base stays on the PV. The cable is a part of that base. You don't need to disconnect anything. Just remove four screws from the inverter (the lid of the enclosure is actually the inverter heat sink), remove it (there's a five pin mating connector inside the inverter .. the female half on the inverter, the male half in the base) .. remove the inverter .. pop the new one in, and replace the four screws. That's it. No wiring to mess with. Dan --- On Wed, 10/31/12, Jason Szumlanski ja...@fafcosolar.com wrote: From: Jason Szumlanski ja...@fafcosolar.com Subject: Re: [RE-wrenches] AC Modules ready for primetime? To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Wednesday, October 31, 2012, 5:27 PM One of the nice features I saw at SPI is the trunk cable which is a standard cable to which you attach piercing taps that come attached on a drop from each AC module's inverter. I like not having to worry about connector spacing. I'm not sure how you handle replacements or removals, but I'm sure that's been addressed. I haven't used these modules yet, but I can see the benefits in the cable strategy. Jason Szumlanski Fafco Solar On Wed, Oct 31, 2012 at 3:30 PM, Exeltech exelt...@yahoo.com wrote: Hello Kirk, Our PVAC Modules are certified to UL and other applicable Standards on: Helios PV, Milwaukee, Wisc ( http://www.heliossolarworks.com/ ) PV made in Milwaukee + our AC Module inverters made in Fort Worth yields a 100% Made in America product. NB Solar (made by Sun Earth Solar), China In the PV business for 44 years. ( http://www.nbsolar.com/ ) Top Sun (Korea) Vertically integrated PV manufacturer of ingots, wafers, cells, and PV modules. ( http://www.topsun.kr/english/main/main.htm ) Distributed by Solarbine, with offices/warehouse facilities in Pennsylvania, Texas, and Southern California. ( http://www.solarbine.net/ ) More PV manufacturers are working their way through in UL certification at this time, but non-disclosure agreements won't allow discussion yet. Dan Lepinski, Senior Engineer Exeltech Solar --- On Wed, 10/31/12, Kirk Herander k...@vtsolar.com wrote: From: Kirk Herander k...@vtsolar.com Subject: Re: [RE-wrenches] AC Modules ready for primetime? To: 'RE-wrenches' re-wrenches@lists.re-wrenches.org Date: Wednesday, October 31, 2012, 1:53 PM Dan, What panel OEM’s are using your AC modules? Kirk HeranderVT Solar, LLC dba Vermont Solar EngineeringNABCEPTM Certified Inaugural Certificant NYSERDA-eligible InstallerVT RE Incentive Program Partner 802.863.1202 From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Exeltech Sent: Wednesday, October 31, 2012 12:05 PM To: RE-wrenches Subject: Re: [RE-wrenches] AC Modules ready for primetime? Hello David, Our inverters are a *true* AC Module, not just a micro-inverter that's been attached to the PV frame or other structure. They replace the junction box on PV, and must be installed by a PV manufacturer, distributor, or OEM that are certified to the appropriate UL Standards for that process. Our AC Modules are not designed for field/site installation to PV. The advantages to this: We're exempt from DC-side ground-fault and arc-fault because all DC conductors are internal to our inverter, and are all less than 80Vdc. Being mounted directly to the PV eliminates the j-box, diodes, high-voltage DC conductors, and expensive DC connectors and their associated hassles. This also reduces the product cost and decreases the system installation time. You're also assured of a perfect match of our inverter to the PV. For notes - our AC Module inverters are made in Fort Worth, Texas. Dan Lepinski, Senior Engineer Exeltech Solar --- On Wed, 10/31/12, David Katz dk...@aeesolar.com wrote: From: David Katz dk...@aeesolar.com Subject: Re: [RE-wrenches] AC Modules ready for primetime? To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Wednesday, October 31, 2012, 10:39 AMDan Lapinski, Does Exeltech make a microinverter that can be site-installed? David Katz Sent from my HTC smartphone on the Now Network from Sprint! - Reply message - From: Exeltech exelt...@yahoo.com To: RE-wrenches re-wrenches@lists.re-wrenches.org Subject: [RE-wrenches] AC Modules ready for primetime? Date: Wed, Oct 31, 2012 7:26 am I'd like to correct an error in Jim's statement below related to how we at Exeltech handle warranty. If an AC Module inverter should fail, the entire module does not need to be sent back for warranty -- just the inverter itself. In our case, this involves removing four small screws to separate the inverter from the base. The lid (or top of the enclosure) is the heat sink of the inverter. The base stays attached to the PV. There's no wiring involved. It's all internal
Re: [RE-wrenches] How do we wrenches provide pertinent advice? (was120% rule applying to conductors)
[Advisory: Lengthy Post] Hello William, Rather than focus on a specific instance, I'd like to step back and view the larger situation. Over the years, numerous posts to this list-serv have related to concerns where installers experienced inspection-related problems ranging from individual AHJs to entire departments or other code bodies that at a minimum are inconsistent with code interpretation, and at the other extreme, establish their own code rules. To that point, and the exact thread you reference, what has become a roadblock for an installer in one jurisdiction is approved as fully acceptable in another, as evidenced by the original post. Environmental and other aspects aside for a moment, how can something such as a conductor gauge be deemed safe by one AHJ, yet is ruled unsafe by another? Either it is .. or it isn't. Nick Vida's recent mention of the City of Los Angeles goes exactly to the heart of my comment, where he said the City has its own utility with its own manual of requirements. To quote Nick: Through experience we know what they require, and it often has nothing to do with NEC. If you bring up NEC to them, they usually laugh at you. The arguments by various Wrenches related to and in support of your point in that thread are well thought out and fully supportable by engineering and other analysis. Unfortunately, logic and common sense aren't always the deciding factors, as we all know too well. Regardless of how well proven or supported a position may be, an AHJ may, at their discretion, accept or reject any aspect of a system. If a field inspector red-tags a system, the installer may appeal up the line to the CBO, who may support or overrule the decision by the field inspector. Again, to my point, if this happens, is it because one of them is wrong in the interpretation of the NEC (or the applicable jurisdictional code) .. or is it because they have differing opinions as to what is acceptable?? It all comes down to whomever is highest on that food chain as a decision maker, and their opinion .. hence whim and interpretation. And to your question .. yes .. I fully support the position you and others took related to the conductor size in that thread. Unfortunately, it's not our opinion that counts. For that reason, I, along with many others, are striving diligently to try to bring some sense and sensibility to the NEC, UL Standards, and more. I too serve on the same NEC and UL boards with John Wiles, Bill Brooks, and a host of others. As for the NEC, the final decision rests with a select group of decision-makers known as the National Fire Protection Association and their Review Board. We can submit all the common-sense changes we like .. and the NFPA has the final say as to what does, or doesn't go into the Code. Many proposals for revision were submitted for the 2014 Code. To put this into perspective, the ROP document for Sections 690 and 705 in the new 2014 Code book consisted of more than 1,000 pages. This is larger than the entire NEC itself, and this was for just two Sections. For those not familiar with the process, the ROP contains proposals and NFPA feedback on each one, and whether a proposal has been accepted, rejected, or something in between. Jurisdictions are then free to use, change, or ignore any and all aspects of the NEC as they see fit. To Nick's point above, they do all of the above .. and again .. whim and interpretation. Keep up the good work. Best Regards to All, Dan Lepinski, Senior Engineer Exeltech Solar Veteran of 41 years in solar energy --- On Wed, 10/3/12, William Miller will...@millersolar.com wrote: From: William Miller will...@millersolar.com Subject: Re: [RE-wrenches] How do we wrenches provide pertinent advice? (was120% rule applying to conductors) To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Wednesday, October 3, 2012, 1:58 AM Dan: I am a bit confused by what you say below regarding whim and interpretation. [SNIP!] ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] How do we wrenches provide pertinent advice? (was120% rule applying to conductors)
Look inside the Code book. Page 1, at the bottom. Last paragraph on that page, which begins: This Code is purely advisory as far as NFPA is concerned. Dan --- On Mon, 10/1/12, Drake drake.chamber...@redwoodalliance.org wrote: From: Drake drake.chamber...@redwoodalliance.org Subject: Re: [RE-wrenches] How do we wrenches provide pertinent advice? (was120% rule applying to conductors) To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Monday, October 1, 2012, 10:00 AM Right. The NFPA doesn't have any authority in itself. It is a private corporation. Local municipalities adopt the NEC at their own discretion. At 10:44 AM 10/1/2012, you wrote: Exactly, Another fine example of how the Code works. Anyone out there have the definition of special permission. Any changes have to go back to the NFPA? Really the buck stops at the quasi-judicial authority of the head of the building department. Inspectors are the bearers of that authority. So it all comes downs to anyone can do anything if they can get the AHJ to sign off on it. Mark. On 10/1/2012 6:24 AM, Drake wrote: From 90.4 By special permission, the authority having jurisdiction may waive specific requirements in this Code or permit alternative methods where it is assured that equivalent objectives can be achieved by establishing and maintaining effective safety. ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] How do we wrenches provide pertinent advice? (was120% rule applying to conductors)
William, My point exactly. Unfortunately, vocal inflection isn't easily incorporated into typed text. For an advisory only document, it has, in essence become the law of the land (as we're acutely aware), however subject to the whim and interpretation of the nationwide AHJ hierarchy and their governing/supervisory colleagues. Dan --- On Mon, 10/1/12, William Miller will...@millersolar.com wrote: From: William Miller will...@millersolar.com Subject: Re: [RE-wrenches] How do we wrenches provide pertinent advice? (was120% rule applying to conductors) To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Monday, October 1, 2012, 2:33 PM Dan: The NEC is purely advisory until a political jurisdiction (city, county or state) adopts it and makes compliance mandatory pursuant to obtaining a final inspection clearance. ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Ilsco SGB bonding lug
When in doubt .. ask the manufacturer. Dan --- On Mon, 8/27/12, Kirpal Khalsa solarwo...@gmail.com wrote: From: Kirpal Khalsa solarwo...@gmail.com Subject: Re: [RE-wrenches] Ilsco SGB bonding lug To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Monday, August 27, 2012, 6:42 PM Benn...it looks like that lug has stainless hardware for corrosion resistance as stated on the brochureThat would be the biggest consideration as David Brearly mentioned earlier in regards to rust potential. Stainless hardware and tin plating is equivalent to the WEEB lugsTin plating and stainless hardware is as good as anything else available as far as outdoor ratings are concerned. I see your point that it is not explicitly stated for outdoor usehowever being marketed for use with solar panels also seems to imply rather obviously that it is outdoor rated.in my unofficial opinion. -- Sunny Regards, Kirpal Khalsa NABCEP Certified Solar PV Installer On Mon, Aug 27, 2012 at 4:11 PM, benn kilburn b...@daystarsolar.ca wrote: Thanks for the feedback Wrenches, lots of interesting comments, However I'm still wondering…..How does one confirm that it is specifically approved for outdoor use? Other than assuming it is implied (because it is 'marketed' as a solar lug). As far as I can tell UL 467 does not imply outdoor rated as the aluminum lug GBL-4 is also UL467 listed. See here…GBL LAY-IN AL/CU. As well, and as Gary pointed out with his second link, for a module bonding/grounding method to be acceptable, it must be recognized by the module manufacturer, no?Which means that any new bonding product on the market must have the blessing of each mod mfgr. (by way of letter or mention in its install manual). I have come across inspectors that actually look for this. Jason, you wrote I like the looks of that lug. However, I've been using WEEBs too long to go back now. I agree, and i'm not looking to replace weebs with these, but these certainly seem to have a place in the What do you use for the bonding connection from the ?rails? This SGB lug was suggested for this purpose as well. BennDayStar Renewable Energy Inc. www.daystarsolar.ca * Ph: 780-906-7807 Construction Electrician Solar Photovoltaic Systems CertifiedCertificate # 0007SHAVE A SUNNY DAY On 27/08/12 2:35 PM, Gary Willett g...@icarussolarservices.com wrote: Here's the Ilsco listing from UL, where it's classed as Grounding and Bonding Equipment: http://database.ul.com/cgi-bin/XYV/template/LISEXT/1FRAME/showpage.html?name=KDER.E34440ccnshorttitle=Grounding+and+Bonding+Equipmentobjid=1074099002cfgid=1073741824version=versionlessparent_id=1073988940sequence=1 The GuideInfo for Grounding Bonding Equipment lists: Grounding and Bonding for Photovoltaic (PV) Systems — Grounding and bonding equipment intended for use in PV systems are additionally investigated in combination with the PV module/panel (see QIGU) to the applicable requirements for such products. Installation instructions provided with the PV system (see QIGU) identify the specific grounding and bonding device that has been investigated and intended for use with that system. http://database.ul.com/cgi-bin/XYV/template/LISEXT/1FRAME/showpage.html?name=KDER.GuideInfoccnshorttitle=Grounding+and+Bonding+Equipmentobjid=1074098839cfgid=1073741824version=versionlessparent_id=1073988940sequence=1 Regards, Gary Willett, PE On 8/27/2012 3:20 PM, David Brearley wrote: Yes, sorry. I wasn't speaking of this lug...I like the redesign. Looks quicker and easier and robust. On Aug 27, 2012, at 3:17 PM, Jason Szumlanski wrote: Yeah, but this one is marketed as a solar bonding lug. I think it's safe to say that it appropriately rated for outdoor use. It's always good to double-check, of course. Jason Szumlanski Fafco Solar On Mon, Aug 27, 2012 at 4:11 PM, David Brearley david.brear...@solarprofessional.com wrote: Some of the aluminum lugs are indoor-rated. They have a set screw will rust in an outdoor environment. That's one of the classic John Wiles slides. I'd just watch out for that
Re: [RE-wrenches] Outback with grid charging
David may be on the right track. Check for a newer digital watt-hour meter at your customer's location. Newer watt-hour meters have two channels of metering in an attempt to thwart people who used to flip their mechanical meters over (usually at night) and run them backwards to un-use power, and thus reduce their utility bill. As installed, newer W-H meters consider both channels consumed power, so it won't matter whether the meter is installed correctly, or reversed. If your customer hasn't notified their utility company of their system, this could be the problem. Case in point: When we installed a grid-tied PV system on our home, we obtained a grid-tie agreement with the power company, they came out and replaced our original meter with one that had been reprogrammed, allowing one channel to measure incoming; the other outgoing power. Without that change, we'd have been billed for our consumed power AND our back-fed power, which would have easily increased our bill by 50% or more. Dan, Senior Engineer Exeltech Solar Products --- On Fri, 8/24/12, David Katz dk...@aeesolar.com wrote: From: David Katz dk...@aeesolar.com Subject: Re: [RE-wrenches] Outback with grid charging To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Friday, August 24, 2012, 7:43 AM Check to see if their meter goes backwards. Some utility meters actually charge for power when you are selling. Or maybe they have no wind and a new big flat screen tv that they leave on all the time. David Katz - Reply message - From: Jesse Dahl dahlso...@gmail.com To: Wrenches RE-wrenches@lists.re-wrenches.org Subject: [RE-wrenches] Outback with grid charging Date: Thu, Aug 23, 2012 11:28 pm Hello, I got a call from a family today about a system they had installed recently and they think they have a problem. They claim their electric bill has just about doubled since the system has been installed due to outback using the grid to power the loads instead of the battery bank. They claim the MATE always shows the system buying the exact amount as any load on the system draws. Due to the distance from my shop, I would like to get any ideas on what could cause this before I drive all the way there. What I know about the system: 2 - outback inverters, 48v 2 - whisper 500 wind generators with whisper charge controllers 16 - MK 12v AGMS (8/inverter) I guessing setting, but if anyone has seen this before, I'd like to narrow it down before the drive. Thanks eh! Jesse Sent from my iPad!!! ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org -Inline Attachment Follows- ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Low power production at a winery: DC voltage drop upon SB6000 start-up
Eric, I checked my magic spreadsheet for the BP SX170. Using 800W/m^2 irradiance, and a presumed ambient of 37C (98F), everything appears to be working within specified tolerances. The presumed conditions create exactly your measured Voc, which is why I used them. Other temperature and irradiance combinations will also work... The voltage delta you measured between Voc and Vmpp is within BP's specifications. No PV has a perfect fill factor. Fill factor is the aspect that determines the shape of the V/I curve established when Voc and Vmpp are plotted. The BP you mentioned have a fill factor of 0.769, which is very typical of polycrystalline PV. A perfect fill factor would be 1.0 (Vmpp equal to Voc), which obviously doesn't happen. Thus, all PV have an operating voltage at maximum power that's below the open circuit voltage -- some more than others. Measured: 375Voc 280V at inverter at mpp 14-15A (fluctuating) at mpp Calculated: 375Voc 301V mpp 14.96A mpp Assumed: 800 w/m^2 37C (98F) amb 4,503W array power under above conditions 280V measured at the inverter 14.5A Presuming 301V is correct Vmpp, this equates to: 1.38 ohms total system R, and 290W loss 290W/4503W = 6.44% 6.44% total loss --higher than a 2.5-3% best-practices target, and likely due to slightly oxidized and/or loose connections in the DC-side of the system. Could also be due to long conductor runs, slightly undersized conductors for the amperage and length, or both. As Jeff Quackenbush mentioned, Vmpp is slighly lower than one might expect, but doesn't appear to rise to the level of something that would yet be indicative of something wrong. Dan --- On Sat, 7/21/12, SunHarvest e...@harvesthesun.com wrote: From: SunHarvest e...@harvesthesun.com Subject: [RE-wrenches] Low power production at a winery: DC voltage drop upon SB6000 start-up To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Saturday, July 21, 2012, 3:19 PM Hello Wrenches, I am helping a client troubleshoot a complaint about underproduction of his on-grid system installed about 6-8 years ago. At first I thought I might encounter the bad Kyocera KC120 issue but it turns out they have BP170's, 40 of them for an STC power rating of 6.8kW. Ratings of the BP modules: PTC=150.7, Vmp=35.4, Voc=44.2, Imp=4.8, Isc=5 The system has four panels of ten modules wired in series for a nominal rating of about 350v, 4.8a per string. At the DC disconnect (first accessible combiner) I measured: All strings right at about 375v(oc), 4.7a(mp). After the strings are combined, at the DC input of the SB6000 (with the AC power to the inverter OFF) I measured about 375V as expected. Once the AC power is connected, the SB6000 starts up, and MPP operation is initiated, the DC voltage drops to about 280V, and amps sit between 14 15A. I didn't think the voltage was supposed to drop upon MPP tracking...especially this much. This voltage drop would account for the observed power loss between actual and rated production values. I'm going to check with SMA but I wanted to ask the experts here too, as someone may advise something like, Oh yeah, BP modules have a similar defect as the Kyocera... My questions: Is the DC voltage supposed to drop significantly in MPP mode on these inverters? If not, does this indicate a bad inverter? Anyone know of problems with BP modules manufactured around 2006-2008? The Kyocera modules showed good volts and amps until a load was connected. Seems like a similar issue here. Eric Stikes SunHarvest Solar A Sustainable Energy Group Partner +1 (530) 798 - 3738 www.harvesthesun.com ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Low power production at a winery: DC voltage drop upon SB6000 start-up
Allan's point is well taken. Resistive connections within the PV could easily be another cause for excessive DC-side voltage drop, and clearly merits closer examination. Dan --- On Sun, 7/22/12, Allan Sindelar al...@positiveenergysolar.com wrote: From: Allan Sindelar al...@positiveenergysolar.com Subject: Re: [RE-wrenches] Low power production at a winery: DC voltage drop upon SB6000 start-up To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Sunday, July 22, 2012, 12:25 PM Eric, Without challenging any of Dan's calculations, I will add that the BP SX170 has proven to be prone to failures. You didn't indicate which model of BP170 you have. I think that the SX170s are the model that was the source of BP's conditional recall of modules that could cause roof fires - no, I'm not making this up, but neither is my memory sharp about this. Here's the text of an email dated 10/10/07 from Phil Undercuffler, now at Outback, then at Conergy: BP reports that these failures tend to manifest early in the product life; modules that will have problems will generally fail in the first few years of service. Failure rates are reported as .02% of product distributed in US, .03% in European market Cause: The solder joint inside the low-profile potted J-box on MC connected modules is what is failing. Changes in solder formulation (due to the phase out of lead solder for environmental reasons) and move to heavier gauge wire made it harder to make a good solder joint. Failure of the solder joint causes heating and arcing, which can in certain cases ignite the epoxy material surrounding the joint. BP's concern is the potential for the burning epoxy to ignite flammable materials in the close vicinity of the junction box. BP does not believe that standard roofing materials such as asphalt shingles, tile or metal roofs will be affected by this issue. A dealer can perform tests with a relatively inexpensive infrared thermometer or contact thermal probe. It is best to measure the module from the front, while in operation. Problem modules will show 10-20 C difference between the solder joint and the module field just before failure. For solder connection, gather the following info: Measure VOC and ISC Physical examination, looking for brown or black spots on solder traces Model number Serial number They are rated at +/- 9%, one of the worst specs around at that time. We used quite a few of them at that time and have replaced many of them under warranty, including one entire 40-module commercial array, identical to the one you described. I would still encourage testing individual string outputs for Vmp and Imp under load, to look for significant variances. At worst, it gives you a baseline reading. Also, if you can, look for browned hot spots, visible beneath he glass in the area over where the leads leave the module back. Allan Allan Sindelar al...@positiveenergysolar.com NABCEP Certified Photovoltaic Installer NABCEP Certified Technical Sales Professional New Mexico EE98J Journeyman Electrician Founder and Chief Technology Officer Positive Energy, Inc. 3209 Richards Lane (note new address) Santa Fe, New Mexico 87507 505 424-1112 www.positiveenergysolar.com On 7/22/2012 10:56 AM, Exeltech wrote: Eric, I checked my magic spreadsheet for the BP SX170. Using 800W/m^2 irradiance, and a presumed ambient of 37C (98F), everything appears to be working within specified tolerances. The presumed conditions create exactly your measured Voc, which is why I used them. Other temperature and irradiance combinations will also work... The voltage delta you measured between Voc and Vmpp is within BP's specifications. No PV has a perfect fill factor. Fill factor is the aspect that determines the shape of the V/I curve established when Voc and Vmpp are plotted. The BP you mentioned have a fill factor of 0.769, which is very typical of polycrystalline PV. A perfect fill factor would be 1.0 (Vmpp equal to Voc), which obviously doesn't happen. Thus, all PV have an operating voltage at maximum power that's below the open circuit voltage -- some
Re: [RE-wrenches] Smart grid grid-connected compatibility
Kent, Life should be so easy as to be able just to tweak the firmware and make things all better. The moment a change is made to the firmware where the zero-crossing detection is involved .. UL safety standards mandate the inverters must undergo re-certification to the applicable aspects of UL1741. In this case, it would mean retesting to IEEE 1547 (anti-islanding) to prove the change in the firmware hasn't affected any aspect of the inverter disconnect under abnormal line conditions -- and possibly other retesting as well. Such a firmware change may also render all modified units incompatible with the manufacturer's communication schemes presently in place. Not to defend a competitor .. but likely every grid-tie inverter maker would be in the same situation here if the TWACS system causes inverters to see what's perceived as an abnormal line condition, and they cease producing power as a result. Likely an engineering solution can be found, but it would extend beyond what even most advanced installers would be able to derive (though there may be a rare few out there who could solve this on their own...). This now becomes a situation where our industry needs to sit down with the monitoring industry to create a workable answer. Dan --- On Sun, 7/8/12, Kent Osterberg k...@coveoregon.com wrote: From: Kent Osterberg k...@coveoregon.com Subject: Re: [RE-wrenches] Smart grid grid-connected compatibility To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Sunday, July 8, 2012, 7:40 PM Chris, SCRs are capable of creating voltage spikes that cause noise well into the radio frequencies. But with TWACS there is an inductor in series with the SCR that is tuned such that the pulse caused when it fires is 0.5 ms to 1.0 ms wide with very little high frequency content. Because the frequency content is very low, it difficult to filter out. Ferrite toroids are of no help and large capacitors will prevent the utility from reading the meter too. The pulse location is near the zero crossing so it makes for a dirty looking waveform for about 8 seconds while the meter is sending data. Never-the-less, it's actually easy to make a reliable frequency measurement by shifting the measurement threshold off zero far enough that the TWACS signal doesn't interfere. The Enpase folks should be able to do that with a firmware change. Kent Osterberg Blue Mountain Solar, Inc. www.bluemountainsolar.com t: 541-568-4882 On 7/8/2012 4:47 PM, Chris Mason wrote: Kent, I haven't any direct experience with the smart meters tripping inverters, but the issue of SCRs and generators is well known. I suspect you understand the problem, but to recap it, the problem revolves around the way SCRs make a sine wave. A motor driven generator controls the alternator output by increasing or decreasing the DC excitation level. It does that by sensing the zero crossing, or point in the sine wave at which the voltage is zero. This happens 120 times a second on a 60Hz system. When the source of the electricity is electronic, the waveform will sometimes be messy around the zero crossing. That gives the voltage control circuit problems to detect the zero crossing We see this a lot when trying to drive a UPS from a generator, it can drive the generator crazy. I suspect your problem is the same. The SCR in the meter disturbs the waveform and the inverter thinks it is a faulty waveform. I would try a low pass filter between the meter and the inverter. A properly sized capacitor ought to remove any noise above 60hz and present a clean waveform to the inverter. On Sun, Jul 8, 2012 at 7:06 PM, Kent Osterberg k...@coveoregon.com wrote: Wrenches, There weren't very many replies to my question about grid-connected inverter compatibility with utility remote meter reading systems so I'll explain my recent experience with hope that this information may be of assistance sometime. Last fall I installed an Ephase system for a customer. Soon after it was on line he complained that the inverters were dropping off line frequently. Since we had a lot of cloudy weather in northeast Oregon all winter, it wasn't easy to see what was going on. In the spring we had some clear days and noticed that the inverters were dropping off line several times a day at exactly the same time every day. It didn't take very long for our suspicion to turn to the utilities new remote meter reading equipment. Because our
Re: [RE-wrenches] bye-bye Schott
1Soltech manufactures PV near Dallas, Texas. http://www.1soltech.com/ Helios manufactures PV in Milwaukee. http://www.heliossolarworks.com/ Solar Power Industries manufactures PV near Pittsburgh. http://www.solarpowerindustries.com/ Dan --- On Fri, 6/29/12, Marco Mangelsdorf ma...@pvthawaii.com wrote: From: Marco Mangelsdorf ma...@pvthawaii.com Subject: [RE-wrenches] bye-bye Schott To: 'RE-wrenches' re-wrenches@lists.re-wrenches.org Date: Friday, June 29, 2012, 3:49 PM One of my favorite manufacturers announced that they are leaving the PV modco business. Very sad. So I’m now looking for an American-made PV module...other than SolarWorld. I’m looking into Suniva. Anybody have any feedback on this brand? Or any other suggestions for a U.S.-made module? Thanks, marco ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Number of Controllers
I second Larry's recommendation of Blue Sky charge controllers. I've used them for several years under some very adverse conditions, yet they've performed flawlessly. Support too has been excellent. Dan Sr. Engineer Exeltech --- On Wed, 5/23/12, Larry Crutcher, Starlight Solar Power Systems la...@starlightsolar.com wrote: From: Larry Crutcher, Starlight Solar Power Systems la...@starlightsolar.com Subject: Re: [RE-wrenches] Number of Controllers To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Wednesday, May 23, 2012, 11:54 PM Colin, The IPN Network charge controllers from Blue Sky Energy can be configured as Master Slave so ALL controllers work together. With up to 8 controllers on the network, you can have multiple arrays and orintations. Their new Duo model will function as hydro or wind diversion control. AND, each controller has a fully programmable lighting control! Sounds like this is the controller to meet all your requests. We have sold hundreds and I highly recommend them. Larry CrutcherStarlight Solar Power Systems(928) 342-9103www.starlightsolar.com Retail Store Warehouse2998 Shari Ave.Yuma, Az 85365 USPS Postal Mail Only11881 S Fortuna Road, #210Yuma, AZ 85367 On May 23, 2012, at 6:47 PM, Colin Vogt wrote: Wrenches, What considerations are there for the number of charge controllers that can be in a stand-alone system with a single battery bank? If one uses MPPT controllers, then one would want (I think) a different controller for different module orientations. That is, if one had a couple modules at one azimuth/tilt angle you would have a controller for that, and another controller for a module at a different azimuth/tilt angle. Also, I can see having a controller to turn on yard lights (Morningstar makes one, although it is not an MPPT type and is of limited capacity). Could also one have a controller for diversion loads? And also a controller for a wind generator? So I can see where a stand-alone system might have 4 or maybe even more controllers, all tied into the same battery bank. Are there any considerations for a system like this? For instance, do the setpoints for all controllers need to match? Colin Vogt ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Nickel-Iron Batteries
Bob is correct in his warning about the Chinese Ni-Fe cells. As I recall, they had a translucent white case, but there may have been others .. and as Bob mentioned, they did indeed have a very high failure rate. Thanks Bob for remembering this. Mine are (and were) Edison cells, and were imprinted with the word Edison on the caps and the cell cases. A quick word of advice ... You *can* get the charge voltage (and subsequently current) too high in the sense the cells out-gas hydrogen and oxygen just like lead-acid, and will do so vigorously when fully charged. The plates won't warp due to heat as will lead-acid, but the risk of of an H2 explosion is still very real. This also causes the electrolyte to be deposited all over the tops of the cells and elsewhere. It's oily and difficult to clean up. Dan --- On Mon, 5/7/12, bob ellison reelli...@gmail.com wrote: From: bob ellison reelli...@gmail.com Subject: Re: [RE-wrenches] Nickel-Iron Batteries To: 'RE-wrenches' re-wrenches@lists.re-wrenches.org Date: Monday, May 7, 2012, 4:38 AM The bigger warning is with the Chinese NiFe cells. There was a company importing them 15-20 years or so ago. The failure rate was very high and the factory support was almost nonexistent. Unless you're a tinkerer, they are great cells to stay away from! I know people who use the original Edison cells in power systems and have seen people just using them as a DC source. Don't worry, you can't get the voltage too high when charging them. They just take it. They don't freeze and if I remember correctly, temp does not alter the output either. There are plenty of the original Edison Cells still out there. Later, Bob Ellison ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] power factor
Hello Todd, The short answer to your is this a concern? query, is no. Reactive power is one of the more complex aspects of electric power, and certainly one of the most misunderstood. It can and does involve inductive loads (e.g. motors), capacitive loads (e.g. some types of power supplies), and non-linear loads (e.g. switch-mode power supplies, dimmers, etc.). You likely know (or should know) power factor is the ratio of real power to reactive power consumed by a load. Grid-tie inverters generate real watts, which are then coupled to the grid. When a reactive load in your home is consuming power, and you provide real watts to the load from the inverter, this changes the ratio of real to apparent power consumed by the load as seen by the utility company. Dividing real power by apparent power results in a unit-less value between 0 and 1 that describes this ratio. Let's say a load in your home is consuming 1,200 real watts, and 1,250 apparent watts. This results in a power factor of 1200/1250, which equals 0.96. Pretty darn good. Next, your grid-tie inverter provides 1,000 real watts back to the utility company, which in turn is 1,000 real watts that the utility company no longer needs to provide to the load described above. Thus the net real power consumed as seen by the utility is now 1,200W - 1,000W = 200W. This means they sell only 200 watts to power your load, but the apparent power aspect is still there. End result? 200 real watts / 1250 apparent watts yields a power factor of 0.160. Terrible by any power company standards, yet you've removed 1,000 watts from the grid. This is the value that will be displayed on your meter. Efforts are underway by EPRI and others to help create standards for future generations of grid-tied inverters capable of generating reactive power (where volts and amps are out of phase with each other) to help mitigate this effect. I'm a member of the committee working toward that goal. (No, we're not there yet. It'll take time.) This is a very difficult topic to discuss and explain. Hopefully this helped. Like Tom Cruise said at the end of Top Gun .. It's complicated. Dan --- On Mon, 5/7/12, toddc...@finestplanet.com toddc...@finestplanet.com wrote: From: toddc...@finestplanet.com toddc...@finestplanet.com Subject: [RE-wrenches] power factor To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Monday, May 7, 2012, 9:46 PM wrenches, i have a question about my home's system. i was one of the first net metered systems in our area, so the utility company installed a fancy dual register meter which also displays kvar/power factor. when selling 1 kW today the power factor was .40 and the kvar was 2.37. this sounds horrible. question: is this a concern? todd Sent from Finest Planet WebMail. -Inline Attachment Follows- ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Nickel-Iron Batteries
Review of Ni-Fe versus lead-acid based on 15 years' use: I have a fellow off-grid acquaintance who lives with a bank of nickel-iron batteries - a bank I gave to him many years ago, and it's still working. I too lived off-grid with an Ni-Fe battery system. (Free was good back then - as now.) What Tom mentioned (below) about the wider-than-lead-acid voltage swing during charge/discharge is correct. My system was configured with 20 cells in series as a 24 volt battery. At full charge, the system reached 33 volts. Almost fully discharged, it was 20 volts - depending on the load current draw compared to the battery A-H rating. Yes, this voltage range is a problem for some electronics. There are some advantages to Ni-Fe batteries depending on where and how the battery is used, and some disadvantages as well... Advantage #1: The electrolyte doesn't participate in the charge/discharge process, thus no change in specific gravity. This makes Ni-Fe cells almost impervious to extreme cold. The potassium hydroxide (KOH) doesn't freeze until the cell temperature is approximately -55F, at which point it becomes more of a slush. Even under those conditions, some current is still available from the battery. Advantage #2: Because of advantage #1, there's much less loss of capacity at very cold temperature compared to lead-acid batteries. At -40C, the Ni-Fe capacity is on the order of 85-90% of the rating when warm. Lead-acid batteries would be reduced to 10-20% - if that. Advantage #3: Ni-Fe cells can be discharged almost 100%, then recharged many times without detrimental effect as would be experienced by L-A batteries under the same operating conditions. Advantage #4: Ni-Fe cells can be left in a fully discharged condition for extended periods of time, then recharged, and will exhibit negligible detrimental effects of sitting in a discharged condition. Advantage #5: As mentioned earlier in this thread, Ni-Fe electrolyte can be removed and replenished, somewhat reviving otherwise tired cells. Not to full capacity - but nearly so. (My experience was 90% or so of the original A-H rating could be recovered IF the plates weren't exposed to oxygen for more than a short time.) Advantage #6: Able to withstand moderate overcharge without harm. Plates in Ni-Fe cells are very rigid, and don't warp like their lead-acid counterparts. Conversely, long-term overcharge boils away the KOH electrolyte, exposing the plates to oxygen, which DOES damage them permanently through oxidation, carbon poisoning, (as in C02) and perhaps other contaminants. Advantage #7: No need for temperature compensation during recharge. Disadvantages of Ni-Fe compared to lead-acid: Disadvantage #1: Poor charge efficiency. High quality lead-acid batteries require [nominally] 105%-110% of the energy taken out to recharge them (new). Ni-Fe I've used required 110-130%. In the days of expensive PV, this was a big cost and energy hit. Today - less so .. but it's still there. Disadvantage #2: Higher self-discharge rate. The Ni-Fe battery system I used lost on average 1% per day. Cold temperatures would slow this process - hot would accelerate it. Other Ni-Fe systems familiar to me exhibited similar traits. Disadvantage #3: Much lower energy density (already mentioned in another post). It takes a physically very large Ni-Fe battery to equal the energy storage of an equivalent yet smaller lead-acid battery. Disadvantage #4: Messy. Ni-Fe cells out-gas for a long time during the absorption phase of the recharge cycle. For that reason, they're also not a sealed battery - ever. This makes them a high-maintenance aspect of a system. Cells often have a dispersal cap intended to allow only gas to escape, but this doesn't always stop 100% of the vented gas and vapor. As a consequence, cell tops require periodic cleaning. Disadvantage #5: Many connections. Ni-Fe are typically available as 1.2 volt cells. This makes them a hassle to install. Some Ni-Fe manufacturers provide custom inter-cell jumpers, which mitigates some of the installation pain. I don't know this to be true of all brands. Disadvantage #6: Most charge controllers I'm familiar with today lack the ability to handle the voltage range of alkaline cells, especially the higher voltage required for their proper recharge. I'm not acquainted with every CC on the market, so can't say this statement is definitive. --- In summary, having lived off-grid with both alkaline and lead-acid technologies, and having worked extensively with both, I would only recommend the use of Ni-Fe batteries if specific circumstances warranted it. Otherwise, lead-acid are in my opinion generally more user-friendly. Regards to all, Dan Sr. Engineer Exeltech --- On Sun, 5/6/12, Tom Duffy t...@thesolar.biz wrote: From: Tom Duffy t...@thesolar.biz Subject: Re: [RE-wrenches] Nickel-Iron Batteries To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Sunday, May 6, 2012, 6
Re: [RE-wrenches] Washington made
Mark, Itek Energy also has a Made in Washington inverter. Dan --- On Wed, 4/18/12, Mark Dickson m...@oasismontana.com wrote: From: Mark Dickson m...@oasismontana.com Subject: [RE-wrenches] Washington made To: 'RE-wrenches' re-wrenches@lists.re-wrenches.org Date: Wednesday, April 18, 2012, 4:50 PM Hello Wrenches, We have been asked to participate in a small bid on Washington State . I am having a hard time finding made in Washington grid-tied inverters and solar modules in order to fulfill their rebate requirements. So far I have come across Silicon Energy and Itek Energy. A micro-inverter would be a plus. Are there any others that I should be looking into? Best regards, Mark Dickson, NABCEP Certified Solar PV Installer ™ Oasis Montana Inc. ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Wood boiler ignition issue
Adding a capacitor of that size across the inverter's output may cause problems for the inverter. Much depends on how the inverter's output voltage control loop is designed, among other things. Before making any changes of this nature, I highly suggest contacting the inverter manufacturer to ask them what issues (if any) may result from such a modification. In turn, they may request from you more detail about nature of the load the inverter will be powering. Is it reactive (and if so, what's the power factor)? Linear or non-linear? And so forth It would be helpful to if you have this information available before you call them. Regards, Dan Lepinski Senior Engineer Exeltech --- On Tue, 3/27/12, Brian Faley bfa...@magnumenergy.com wrote: From: Brian Faley bfa...@magnumenergy.com Subject: Re: [RE-wrenches] Wood boiler ignition issue To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Tuesday, March 27, 2012, 4:04 PM Hi Kris, A solution to try would be to add a motor run capacitor across the line at the boiler. 10uF-20uf range may improve the crossover distortion enough to allow the boiler ignitor to operate properly. Start with 10uF. Regards,Brian Brian FaleyChief EngineerMagnum Energy Inc.2211 West Casino RdEverett, WA 98204Ph 425-353-8833www.magnumenergy.com From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Kristopher Schmid Sent: Monday, March 26, 2012 11:51 AM To: RE-wrenches Subject: [RE-wrenches] Wood boiler ignition issue Esteemed wrenches,I am assisting in troubleshooting a stand alone system with three stacked Magnum 4448 PAE inverters. The electric ignition of LP for the wood boiler will not fire from inverter power. As soon as we fire up the generator, the boiler ignites. Has anyone seen this before? Is there a solution? The boiler is a Central Boiler E-Classic 2400.Thanks in advance!-- Shine On!Kris Schmid Legacy Solar, LLC 864 Clam Falls Trail Frederic, WI 54837 715-653-4295 www.legacysolar.com NABCEP Certified PV Installer BSEE -Inline Attachment Follows- ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Wood boiler ignition issue
My apologies. I see this recommendation comes from Magnum. The suggestion is still valid when other brands are involved and parallel capacitors are considered. Dan --- On Tue, 3/27/12, Exeltech exelt...@yahoo.com wrote: From: Exeltech exelt...@yahoo.com Subject: Re: [RE-wrenches] Wood boiler ignition issue To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Tuesday, March 27, 2012, 5:11 PM Adding a capacitor of that size across the inverter's output may cause problems for the inverter. Much depends on how the inverter's output voltage control loop is designed, among other things. Before making any changes of this nature, I highly suggest contacting the inverter manufacturer to ask them what issues (if any) may result from such a modification. In turn, they may request from you more detail about nature of the load the inverter will be powering. Is it reactive (and if so, what's the power factor)? Linear or non-linear? And so forth It would be helpful to if you have this information available before you call them. Regards, Dan Lepinski Senior Engineer Exeltech --- On Tue, 3/27/12, Brian Faley bfa...@magnumenergy.com wrote: From: Brian Faley bfa...@magnumenergy.com Subject: Re: [RE-wrenches] Wood boiler ignition issue To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Tuesday, March 27, 2012, 4:04 PM Hi Kris, A solution to try would be to add a motor run capacitor across the line at the boiler. 10uF-20uf range may improve the crossover distortion enough to allow the boiler ignitor to operate properly. Start with 10uF. Regards,Brian Brian FaleyChief EngineerMagnum Energy Inc.2211 West Casino RdEverett, WA 98204Ph 425-353-8833www.magnumenergy.com From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Kristopher Schmid Sent: Monday, March 26, 2012 11:51 AM To: RE-wrenches Subject: [RE-wrenches] Wood boiler ignition issue Esteemed wrenches,I am assisting in troubleshooting a stand alone system with three stacked Magnum 4448 PAE inverters. The electric ignition of LP for the wood boiler will not fire from inverter power. As soon as we fire up the generator, the boiler ignites. Has anyone seen this before? Is there a solution? The boiler is a Central Boiler E-Classic 2400.Thanks in advance!-- Shine On!Kris Schmid Legacy Solar, LLC 864 Clam Falls Trail Frederic, WI 54837 715-653-4295 www.legacysolar.com NABCEP Certified PV Installer BSEE -Inline Attachment Follows- ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org -Inline Attachment Follows- ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] embedded energy in pv
PV energy payback is listed as 0.7 to 25.5 years, depending on the type of module and the data you elect to use. The preponderance of most opinion/data support 1 to 4 years as the period for the equivalent embodied energy in a PV module to be produced by that module, again depending on the module chemistry (crystalline, film, etc.) and other variables. Citations: www.nrel.gov/docs/fy04osti/35489.pdf http://energybulletin.net/node/17219 http://homepower.com/article/?file=HP127_pg32_Sanchez Dan ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] 30 to 35 kW inverters
Marco, Single phase as in 120V or 240V? We make models in both voltage ranges (up to 120kW @ 208V, three-phase). We can continue off-line unless this is of interest to the entire group. Dan --- On Wed, 2/22/12, penobscotso...@midmaine.com penobscotso...@midmaine.com wrote: From: penobscotso...@midmaine.com penobscotso...@midmaine.com Subject: Re: [RE-wrenches] 30 to 35 kW inverters To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Wednesday, February 22, 2012, 11:41 AM I'm not sure how many Radians you can stack, but they are a great inverter. Exeltech also makes a buildable line of inverters and you might ask Dan there about them. I also think Apollo is coming out soon with the ability to stack multiple inverters to get there. The redundancy of stackable is nice for off grid use. Daryl Anyone know of any single-phase inverters out there in the 30-35 kW range? Thanks, marco ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Interstate L-16 vs Trojan L-16REB
Carl, I've got two sets of Surette lead-calcium in an off-grid test system. The electrolyte is H2S04 .. sulfuric acid. The internal construction of these batteries is more open than I've seen in other L16 style cells (more space between the plates), which may (or may not) lend itself to lessening of stratification issues. Dan --- On Thu, 2/16/12, Carl Hansen solar...@cybermesa.com wrote: From: Carl Hansen solar...@cybermesa.com Subject: Re: [RE-wrenches] Interstate L-16 vs Trojan L-16REB To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Thursday, February 16, 2012, 3:12 PM I've heard that Lead-calcium batteries do not need Equalization, I think because the electrolyte does not contain sulfates so the lead plates cannot get sulfated. Although maybe electrolyte stratification is still an issue. Can anyone confirm that this info is correct ? Carl, ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] AL vs CU
AL advantage: Weight (especially in long overhead runs). Theft factor (less attractive than CU to thieves at the moment). CU advantage: Smaller conductors for a given current. CU-friendly lugs are readily found on the shelf. Ease of attachment to hardware. Less brittle/more flexible than AL. Commonly available in a variety of gauges. Common to both: Both metals corrode if improperly protected. AL/CU recognized splice blocks alleviate dissimilar metals issues. Likely there are many more. There's a wealth of experience in this group. Dan --- On Mon, 2/13/12, James Rudolph jamesrudolp...@gmail.com wrote: From: James Rudolph jamesrudolp...@gmail.com Subject: [RE-wrenches] AL vs CU To: RE-wrenches re-wrenches@lists.re-wrenches.org Date: Monday, February 13, 2012, 10:35 AM Gurus, Other than the cost and increased labor what else could be a factor in determining whether or not to use copper or aluminum in long output circuits? -- James B Rudolph NABCEP Certified PV Installer California Certified Journeyman Electrician Don't get me wrong: I love nuclear energy! It's just that I prefer fusion to fission. And it just so happens that there's an enormous fusion reactor safely banked a few million miles from us. It delivers more than we could ever use in just about 8 minutes. And it's wireless! - William McDonough ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Inverters and cold temps?
Exeltech's AC Module inverters are NTRL certfied to -40C. --- On Mon, 1/16/12, benn kilburn b...@daystarsolar.ca wrote: From: benn kilburn b...@daystarsolar.ca Subject: Re: [RE-wrenches] Inverters and cold temps? To: Wrenches re-wrenches@lists.re-wrenches.org Date: Monday, January 16, 2012, 7:47 PM Jessie, Dan with Exeltech just gave some good insight to cold weather inverter capacitor tolerances in the thread Electrolytic Caps vs. Thin Film Caps. We had -26C here (Edmonton) today and the next couple of days are looking like minimum -30C with windchill on top of that. This is pretty typical at least a few times a winter season. I have one install, circa 2006, with two SMA's outside and have no issues. I know that Enphase and SUNERGY PV Inverters are rated to -40C, but no others come to mind. I would stick to the manufacturers that spec their equipment for -40C. divbundling up for the cold...benn DayStar Renewable Energy Inc. benn@daystarsolar.ca780-906-7807 HAVE A SUNNY DAY From: dahlso...@gmail.com Date: Mon, 16 Jan 2012 18:21:17 -0600 To: re-wrenches@lists.re-wrenches.org Subject: [RE-wrenches] Inverters and cold temps? All, I live in an area where -40F is not uncommon and where -60F has been seen. (northern MN) I have yet to see an inverter that can be placed in locations like this and not exceed the warranty temp extremes. Enphase has a cold temp acceptability of -40F last time I checked, and when I called they told me about an install in Antarctica using micros. I have installed inverters outside in the twin cities, not up here. What do you think about this problem? Thanks as always, Jesse Sent from my iPhone ___ List sponsored b y Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org -Inline Attachment Follows- ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] 24 vs. 48
The most common reason to go with a higher voltage (and thus lower current for a given overall wattage) is to allow the use of smaller conductors, which are generally easier to work with, and lower cost. There are fractional performance advantages to 48V over 24V in *some* equipment, but the advantages typically require lab-grade equipment to measure. Equipment such as charge controllers and MPPT often benefit from operating at a higher voltage due to reduced energy loss in the copper. The above aside, Nathan appears to have mis-typed when he said: Wire sizing might be reduced on the low voltage side of hings. Wire sizes *increase* for a lower-voltage system at a given wattage and the same conductor losses as in a higher-voltage configuration. A 24V system will have double the current than a 48V system at the same wattage. Larger conductors are needed if the loss is to be the same in the 24V as in the 48V configuration. Dan Sr. Engineer Exeltech Dan --- On Tue, 1/17/12, Nathan Jones solardud...@yahoo.com wrote: From: Nathan Jones solardud...@yahoo.com Subject: Re: [RE-wrenches] 24 vs. 48 To: re-wrenches@lists.re-wrenches.org Date: Tuesday, January 17, 2012, 12:11 PM Mark, It would seem to be a wash. As the voltage is halved the amperage is doubled in the battery bank. This would seem to require doubling the charging amperage so nothing is gained. On a system of any size the 48 volt gets the default nod here. Charge controllers handle twice the solar. Parallel battery strings are eliminated, or at least held to two. Wire sizing might be reduced on the low voltage side of things. And much easier future expansion possibilities, too. Cheers, Nathan Jones Power Source Solar Inc -- On Tue, Jan 17, 2012 10:56 AM CST Mark Frye wrote: Not really on topic to Jay's question, but... Is 48v always better than 24v? How important is bulk charging current to overall battery life? In some cases, isn't it better to use a 24v inverter/charger which can develop a higher charge current for a battery bank that has a higher AH rating? Mark Frye Berkeley Solar Electric Systems 303 Redbud Way Nevada City, CA 95959 (530) 401-8024 www.berkeleysolar.com ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
