Re: [RE-wrenches] 24 volt Battery Bank comparison
I am glad to see this issue with series strings being brought into the discussion. At 11:53 -0600 3/6/11, Ray Walters wrote: I've had single strings with equal current through each battery, but some batteries would be at 15.5 volts, while others next to it would be at 13. The charge controller shuts off when the sum of the voltages hits the bulk charge V, but meanwhile some cells are chronically overcharged or undercharged. (parallel strings no where to be seen) and.. At 15:10 -0300 3/6/11, James Surrette wrote: If you hook up 4 x 12V monoblocks for a small 48VDC system and begin charging at 58.8V, total voltage will be 58.8V very quickly but individual battery voltage will not be 14.7V. Battery voltage will have a large range from 14 to almost 17V. If you have 4 x 12V monoblocks, they will thrive much better connected in parallel than they will in series. The parallel strings discussion reappears regularly on this list, and always produces a chorus of disapproval, but I think the downsides are over-stated. Most battery charging regimes are based on bringing the battery up to a specific voltage and holding the voltage there for a period of time. This can he achieved with perfect equality for strings of batteries in parallel. (Yes technically you may need to use bus-bars to get within millivolts of each other but to be honest who really knows the optimum absorption voltage that exactly, and does it matter?) So long as the battery as a whole gets up to and stays at the prescribed voltage for long enough, then all the parallel batteries will get charged according to the manufacturer's instructions. With batteries in series I am finding that 48V systems are much harder to keep properly balanced than in the old days of 12V systems, since the current in one string is the same in every cell, whether it needs it or not. Yes you could put diversion load regulators on individual 12V batteries in the string, but given the way they are priced (by amps) you would end up spending four times as much on charge controllers. To me the issues of unbalanced charging are much worse for batteries in series than they are for batteries in parallel. Now I will go and hide from the wrath of the list :-) have fun, -- Hugh Piggott Scoraig http://www.scoraigwind.co.uk___ 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 volt Battery Bank comparison
I've set electric vehicle parallel strings up like this too. Once a month I charge each string separately. At higher charge/ discharge rates, the problems of unequal batteries increases dramatically. BTW, single strings are not the magic bullet either; I've had single strings with equal current through each battery, but some batteries would be at 15.5 volts, while others next to it would be at 13. The charge controller shuts off when the sum of the voltages hits the bulk charge V, but meanwhile some cells are chronically overcharged or undercharged. (parallel strings no where to be seen) Manzanita Micro makes a device that shunts current past batteries that hit full charge in a string. This monitoring of each individual battery is the state of the art right now for Li+ batteries in EVs. I agree, we need much better battery management and safety devices for solar. Its ridiculous some of the mundane issues we discuss here sometimes, while hundreds of huge battery packs are just waiting for one of us to drop a wrench across the terminals, with zero safety to interrupt it, and its all NEC compliant. Batteries themselves need to have a current limiting device built into the positive terminal. Possibly the same device that controls charge current to it too? Dreaming up future BOS equipment, Ray Walters On 6/2/2011 7:44 PM, d...@foxfire-energy.com wrote: What I like best about Mark's set up (the retired phone co. dude w/ half a hand), is that he can select individual strings at random. he can eq an individual string, or top off a few strings and park them. he can even run strings of T 105s, or even nicad (individually of course) in the same system as L-16s and the like.. he just reprograms the chargers (and logs it). I think he got the design from his days in the Navy. So boB, how about a controller that can be user programed to charge multiple battery configurations with a soft switch? i.e. Bank A, Bank B...? and while you're at it, maybe a multiple string DC box? Something with a shunt and a breaker for each string? A four string set up would be nice. I could use 2% of your first million. db Dan Brown ___ 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 volt Battery Bank comparison
Hi Ray, Just a quick chime in on your series string comment. If you hook up 4 x 12V monoblocks for a small 48VDC system and begin charging at 58.8V, total voltage will be 58.8V very quickly but individual battery voltage will not be 14.7V. Battery voltage will have a large range from 14 to almost 17V. This problem is only exacerbated in higher voltage systems, ie, Australian 120VDC. Stealing from the Telcos, the best solution is an initial activation to balance all cells. When this is completed and assuming all leads stay tight, no bad cells, etc the bank will charge and discharge in relative harmony. However, if the cells / batteries are bolted together and discharged right out of the gate, there's a good chance SG Voltages will be all over the map in short order. Jamie Ray Walters r...@solarray.com 6/3/2011 2:53 PM I've set electric vehicle parallel strings up like this too. Once a month I charge each string separately. At higher charge/ discharge rates, the problems of unequal batteries increases dramatically. BTW, single strings are not the magic bullet either; I've had single strings with equal current through each battery, but some batteries would be at 15.5 volts, while others next to it would be at 13. The charge controller shuts off when the sum of the voltages hits the bulk charge V, but meanwhile some cells are chronically overcharged or undercharged. (parallel strings no where to be seen) Manzanita Micro makes a device that shunts current past batteries that hit full charge in a string. This monitoring of each individual battery is the state of the art right now for Li+ batteries in EVs. I agree, we need much better battery management and safety devices for solar. Its ridiculous some of the mundane issues we discuss here sometimes, while hundreds of huge battery packs are just waiting for one of us to drop a wrench across the terminals, with zero safety to interrupt it, and its all NEC compliant. Batteries themselves need to have a current limiting device built into the positive terminal. Possibly the same device that controls charge current to it too? Dreaming up future BOS equipment, Ray Walters On 6/2/2011 7:44 PM, d...@foxfire-energy.com wrote: What I like best about Mark's set up (the retired phone co. dude w/ half a hand), is that he can select individual strings at random. he can eq an individual string, or top off a few strings and park them. he can even run strings of T 105s, or even nicad (individually of course) in the same system as L-16s and the like.. he just reprograms the chargers (and logs it). I think he got the design from his days in the Navy. So boB, how about a controller that can be user programed to charge multiple battery configurations with a soft switch? i.e. Bank A, Bank B...? and while you're at it, maybe a multiple string DC box? Something with a shunt and a breaker for each string? A four string set up would be nice. I could use 2% of your first million. db Dan Brown This email and its attachments have been scanned by iConnection E-Mail Firewall for viruses, spam, and malicious content. The information transmitted in this email is intended only for the entity or person to which it is addressed and may contain confidential/privileged material. If you received this in error, please contact the sender and delete the material from any computer. Any review, retransmission, dissemination, or other use of this information by persons or entities other than the intended recipient is strictly prohibited. %^^% ___ 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 volt Battery Bank comparison
So would you agree that battery inequalities show up more at: a) high discharge/charge rates (greater than C5) b) higher battery voltages (more cells in series, over 48v) c) more parallel strings d) bad/ corroded/ loose connections e)lack of initial EQ/ activation charge and periodic EQ after long or heavy discharges f) main cables not at least wired to opposite sides of battery bank or better: separate parallel cables to buss bar h) lack of maintenance (watering, uneven cell temperatures) Did I miss anything? Ray On 6/3/2011 12:10 PM, James Surrette wrote: Hi Ray, Just a quick chime in on your series string comment. If you hook up 4 x 12V monoblocks for a small 48VDC system and begin charging at 58.8V, total voltage will be 58.8V very quickly but individual battery voltage will not be 14.7V. Battery voltage will have a large range from 14 to almost 17V. This problem is only exacerbated in higher voltage systems, ie, Australian 120VDC. Stealing from the Telcos, the best solution is an initial activation to balance all cells. When this is completed and assuming all leads stay tight, no bad cells, etc the bank will charge and discharge in relative harmony. However, if the cells / batteries are bolted together and discharged right out of the gate, there's a good chance SG Voltages will be all over the map in short order. Jamie Ray Walters r...@solarray.com 6/3/2011 2:53 PM I've set electric vehicle parallel strings up like this too. Once a month I charge each string separately. At higher charge/ discharge rates, the problems of unequal batteries increases dramatically. BTW, single strings are not the magic bullet either; I've had single strings with equal current through each battery, but some batteries would be at 15.5 volts, while others next to it would be at 13. The charge controller shuts off when the sum of the voltages hits the bulk charge V, but meanwhile some cells are chronically overcharged or undercharged. (parallel strings no where to be seen) Manzanita Micro makes a device that shunts current past batteries that hit full charge in a string. This monitoring of each individual battery is the state of the art right now for Li+ batteries in EVs. I agree, we need much better battery management and safety devices for solar. Its ridiculous some of the mundane issues we discuss here sometimes, while hundreds of huge battery packs are just waiting for one of us to drop a wrench across the terminals, with zero safety to interrupt it, and its all NEC compliant. Batteries themselves need to have a current limiting device built into the positive terminal. Possibly the same device that controls charge current to it too? Dreaming up future BOS equipment, Ray Walters On 6/2/2011 7:44 PM, d...@foxfire-energy.com wrote: What I like best about Mark's set up (the retired phone co. dude w/ half a hand), is that he can select individual strings at random. he can eq an individual string, or top off a few strings and park them. he can even run strings of T 105s, or even nicad (individually of course) in the same system as L-16s and the like.. he just reprograms the chargers (and logs it). I think he got the design from his days in the Navy. So boB, how about a controller that can be user programed to charge multiple battery configurations with a soft switch? i.e. Bank A, Bank B...? and while you're at it, maybe a multiple string DC box? Something with a shunt and a breaker for each string? A four string set up would be nice. I could use 2% of your first million. db Dan Brown This email and its attachments have been scanned by iConnection E-Mail Firewall for viruses, spam, and malicious content. The information transmitted in this email is intended only for the entity or person to which it is addressed and may contain confidential/privileged material. If you received this in error, please contact the sender and delete the material from any computer. Any review, retransmission, dissemination, or other use of this information by persons or entities other than the intended recipient is strictly prohibited. %^^% ___ 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 volt Battery Bank comparison
Wrenches: This is a really great thread. Here’s my two cents… I started selling and configuring battery systems when I got out of the Army back in 1967 I’m a marine electrician. In the boat environment everybody tries to make a big battery out of a bunch of small batteries, Over the years this is what I’ve witnessed; All else being equal. 3 parallel strings = 4 ½ to 5 ½ years Max 2 parallel strings = 5 ½ to 6 ½ years Max 1 series string = 8 to 12 years Max The above seems to hold true if the charge settings, Bulk, Absorb time and Voltage are correctly set. But as we all know 85% of the time this is not the case. So my conclusion is that parallel configured banks just about cut the life in half. And there is always the stories about the guy that drank a quart of Bourbon a day and smoked cigars chasing women until he was 102 years old. The same is true with batteries… the exception but not the rule. Tom Duffy Systems Design Engineer t...@thesolar.biz 575-539-2111 X 122 Although no trees were killed in the sending of this message, a large number of electrons were terribly inconvenienced. Confidentiality Notice: This message including any attachments is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender and delete any copies of this message. _ From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Allan Sindelar Sent: Wednesday, June 01, 2011 11:07 PM To: re-wrenches@lists.re-wrenches.org Subject: Re: [RE-wrenches] 24 volt Battery Bank comparison I had done this a few times in the distant past, and also had done it in recent years on my own previous battery bank (four strings of S-530s - yes, I know; it was in anticipation of future plans to upgrade to 48V, and two strings wouldn't have been enough). It worked fine - and that turned out to be a problem. I had noticed reduced capacity, but assumed foolishly that it was simply to age and cycle life (going on six years and three teenagers). Found out I had two failed cells in two different strings. The parallel connections probably - I'm not sure here - allowed the bank to perform more robustly and less obviously weakened. It might have even allowed the bank to perform as if both failed cells had been in the same string. But it also allowed me to not pay enough attention to a potentially serious problem by disguising it. I blame myself more than the parallel connectors (just some #2 interconnects I had lying around). I'm just not sure I would use it on a customer's system. Allan Sindelar mailto:al...@positiveenergysolar.com al...@positiveenergysolar.com NABCEP Certified Photovoltaic Installer NABCEP Certified Technical Sales Professional New Mexico EE98J Journeyman Electrician Positive Energy, Inc. 3201 Calle Marie Santa Fe, New Mexico 87507 505 424-1112 www.positiveenergysolar.com http://www.positiveenergysolar.com/ On 6/1/2011 9:20 AM, toddc...@finestplanet.com wrote: Does it make any difference to do as boB recently suggested and inter-connect the strings? So in other words, if you have two parallel strings, what happens if you parallel each battery in one string with the battery in the other string? Has anyone tried this? It might help insure more balance between each series string. Todd On Wednesday, June 1, 2011 3:06am, James Surrette mailto:ja...@surrette.com ja...@surrette.com said: Hi boB, I would say maintenance is a large issue - especially when dealing with L-16's or the like, as the number of cells connections gets large, i.e. 1000-1200AH @ 48VDC is three (3) strings, 24 batteries and 72 cells. Will a client water 24 cells...maybe - 72?? However, from Tech Support days, imbalance is the larger problem. It seems to take 18 months - 3 years and then you would get SG readings where one (1) bank was perfect and the other(s) is significantly lower..which is hard to overcome without effort (either break the banks charge independently or hammer the banks and allow the high string to get even higher). One of the key take aways that often gets overlooked is the proper initial activation of the strings. It is impossible for all cells to have identical resting voltage. During commissioning, each string should be charged to 2.45-2.5VPC and held until all cells read the same voltage. If running multiple strings, then connect the strings and run the entire bank at 2.45-2.5VPC until all cells measure the same voltage. Now the bank is well balanced and the chances of a major imbalance are greatly reduced. However, even after this effort, if you use an amp clamp, you will notice slight differences in the amount of current being accepted by each bank. Best
Re: [RE-wrenches] 24 volt Battery Bank comparison
This has been a great string. Battery systems and the weather are the most variable things we all have to deal with- and the most misunderstood. I totally agree with Darryl here and it makes common sense. PV cells are manufactured under seriously strict controls and nearly entirely by machines and robotics, yet they still have variance from one individual cell to the next. Battery manufacture is better than that? No way. Having just one string doesn't get you away from the variables, just lessens their impact over many cycles and years. Bob-O On Jun 2, 2011, at 9:47 AM, Darryl Thayer wrote: it is due to differences in the strings; in charging and in discharging differentials. this is due to temp differences very small differences in connections and differences in the cells themselves. Darry From: boB Gudgel b...@midnitesolar.com To: Darryl Thayer daryl_so...@yahoo.com; RE-wrenches re-wrenches@lists.re-wrenches.org Sent: Thursday, June 2, 2011 11:32 AM Subject: Re: [RE-wrenches] 24 volt Battery Bank comparison On 6/2/2011 9:03 AM, Darryl Thayer wrote: Excellent comment tom, so true. I get concerned that some of my experiences are a collection of exceptions. I like Larry's comments because he has worked so many systems. I have seen fires, but mostly because I have a reputation and people wnat me to come and see what happened. Darryl Now my question would be... Why ? I have to think that with more batteries in the system, they are just not getting charged as well. If that's the case, I think this could be fixed. Haven't battery chargers and education gotten better since 1967, Tom ? boB ___ 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 volt Battery Bank comparison
Not surprised at all about the phone company guy. It was a phone company guy who read me the riot act that no one in their right minds would ever parallel battery banks the way PV off-grid systems did and got me to set up my system with separate strings connected independently to buss bars. The battery engineer I talked to years ago at Dynasty not only said the same thing but also said keeping strings separate meant individual string distance from the bars became irrelevant (given correctly sized wire for each string’s parallel connectors). I had a system with 12 100 amphour strings of paired 12v Dynasty AGMs which was rock solid until the day I sold the house. The last time I checked the system before the sale no single battery varied from any other in the system by more than 1/10 volt and the majority were still holding identical voltages. From: d...@foxfire-energy.com Sent: Wednesday, June 01, 2011 4:14 PM To: RE-wrenches Subject: Re: [RE-wrenches] 24 volt Battery Bank comparison Good thread. Thanks. In my experience, it all boils down to the customer. I've seen one temp. set up with like 12 strings (for a concert). but they were recharged and sold individually within a few weeks.. I've also seen a single string (Teledyne aircraft batteries) fail in less than a year.. they were in a brand new airplane tug that was never charged -- ever. (the guy said I dunno, it just stopped working). I have one customer who (last I knew) was running 6 strings of mixed aged L-16s going on 8 years. Thing is, he's a retired phone company dude (Who's missing half of his right hand from using one of those pocket pal screwdriver thingys on a key chain in a hot DC rack.. like he'd done hundreds of times before.. but that's another tale). But I do like his set up.. he has each string set up with it's own fused Disco and Trimetric.. Gives him random control over each string. And yes, he keeps a very detailed log, and you can bet that when he takes a battery out of service, it's done. Me? for an average bullet proof off grid system, I shoot for a max of two strings for 24V systems (for the redundancy), and manually reconfigure them every few years. for 48V systems, I shoot for one string of two Volt cells.. thinking that if I loose a cell I can still operate a 46V system until I get a replacement. And Yes, as we all know, there are folks out there that really shouldn't be allowed to operate a popsicle stick. db Dan Brown Foxfire Energy Corp. Renewable Energy Systems (802)-483-2564 www.Foxfire-Energy.com NABCEP #092907-44 Original Message Subject: Re: [RE-wrenches] 24 volt Battery Bank comparison From: Michael Welch michael.we...@re-wrenches.org Date: Wed, June 01, 2011 1:43 pm To: RE-wrenches re-wrenches@lists.re-wrenches.org Every now and then I see reference on this list to the need for thermal detection. Here is an interesting, inexpensive piece of equipment that could be used for finding hot (loose or corroded) connections, hot batteries, hot PV cells in modules, and even poorly insulated spots, its original intended purpose: http://www.blackanddecker.com/power-tools/TLD100.aspx I have one and used it for finding uninsulated spaces, but cannot attest to its durability or suitability for the other uses mentioned above. boB Gudgel wrote at 01:00 AM 6/1/2011: This might be a good reason for an installer to have one of those FLIR (or similar) thermal imager cameras.  They're a bit on the expensive side, but could really be helpful for so many things.  Even just to know if you have left a nut loose (under load of course) boB ___ 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 No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1375 / Virus Database: 1511/3673 - Release Date: 06/01/11 ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options
Re: [RE-wrenches] 24 volt Battery Bank comparison
Nobody mentioned this in this thread, but it occurs to me that the answer may be made clearer by looking at the Voc of each battery string after so many Amp-Hours (years) of service. i.e., disconnect the strings' parallel connection and measure the individual string voltage after charging them all the best that can be done. This would be making the assumption that the batteries themselves were fairly equal capacity and voltage at installation time. And for whatever reasons, connections, temperatures and everything else discussed here, the strings degrade differently. The older and more worn out batteries should have a lower voltage (Voc) than the less worn out strings. Thus, the better strings may be tending to hold up the worse strings by dumping charge into them when the whole bank is discharging, and wasting energy and battery efficiency. I guess that just large 2V cells are the answer in this case, if at all possible. Thanks for the help on this question ! boB On 6/2/2011 10:42 AM, Tom Elliot wrote: Not surprised at all about the phone company guy. It was a phone company guy who read me the riot act that no one in their right minds would ever parallel battery banks the way PV off-grid systems did and got me to set up my system with separate strings connected independently to buss bars. The battery engineer I talked to years ago at Dynasty not only said the same thing but also said keeping strings separate meant individual string distance from the bars became irrelevant (given correctly sized wire for each string’s parallel connectors). I had a system with 12 100 amphour strings of paired 12v Dynasty AGMs which was rock solid until the day I sold the house. The last time I checked the system before the sale no single battery varied from any other in the system by more than 1/10 volt and the majority were still holding identical voltages. *From:* d...@foxfire-energy.com mailto:d...@foxfire-energy.com *Sent:* Wednesday, June 01, 2011 4:14 PM *To:* RE-wrenches mailto:re-wrenches@lists.re-wrenches.org *Subject:* Re: [RE-wrenches] 24 volt Battery Bank comparison Good thread. Thanks. In my experience, it all boils down to the customer. I've seen one temp. set up with like 12 strings (for a concert). but they were recharged and sold individually within a few weeks.. I've also seen a single string (Teledyne aircraft batteries) fail in less than a year.. they were in a brand new airplane tug that was never charged -- ever. (the guy said I dunno, it just stopped working). I have one customer who (last I knew) was running 6 strings of mixed aged L-16s going on 8 years. Thing is, he's a retired phone company dude (Who's missing half of his right hand from using one of those pocket pal screwdriver thingys on a key chain in a hot DC rack.. like he'd done hundreds of times before.. but that's another tale). But I do like his set up.. he has each string set up with it's own fused Disco and Trimetric.. Gives him random control over each string. And yes, he keeps a very detailed log, and you can bet that when he takes a battery out of service, it's done. Me? for an average bullet proof off grid system, I shoot for a max of two strings for 24V systems (for the redundancy), and manually reconfigure them every few years. for 48V systems, I shoot for one string of two Volt cells.. thinking that if I loose a cell I can still operate a 46V system until I get a replacement. And Yes, as we all know, there are folks out there that really shouldn't be allowed to operate a popsicle stick. db Dan Brown Foxfire Energy Corp. Renewable Energy Systems (802)-483-2564 www.Foxfire-Energy.com http://www.Foxfire-Energy.com NABCEP #092907-44 Original Message Subject: Re: [RE-wrenches] 24 volt Battery Bank comparison From: Michael Welch michael.we...@re-wrenches.org mailto:michael.we...@re-wrenches.org Date: Wed, June 01, 2011 1:43 pm To: RE-wrenches re-wrenches@lists.re-wrenches.org mailto:re-wrenches@lists.re-wrenches.org Every now and then I see reference on this list to the need for thermal detection. Here is an interesting, inexpensive piece of equipment that could be used for finding hot (loose or corroded) connections, hot batteries, hot PV cells in modules, and even poorly insulated spots, its original intended purpose: http://www.blackanddecker.com/power-tools/TLD100.aspx I have one and used it for finding uninsulated spaces, but cannot attest to its durability or suitability for the other uses mentioned above. boB Gudgel wrote at 01:00 AM 6/1/2011: This might be a good reason for an installer to have one of those FLIR (or similar) thermal imager cameras.  They're a bit on the expensive side, but could really be helpful for so many things.  Even just to know if you have left a nut loose (under load of course) boB
Re: [RE-wrenches] 24 volt Battery Bank comparison
On 6/2/2011 6:44 PM, d...@foxfire-energy.com wrote: What I like best about Mark's set up (the retired phone co. dude w/ half a hand), is that he can select individual strings at random. he can eq an individual string, or top off a few strings and park them. he can even run strings of T 105s, or even nicad (individually of course) in the same system as L-16s and the like.. he just reprograms the chargers (and logs it). I think he got the design from his days in the Navy. So boB, how about a controller that can be user programed to charge multiple battery configurations with a soft switch? i.e. Bank A, Bank B...? and while you're at it, maybe a multiple string DC box? Something with a shunt and a breaker for each string? A four string set up would be nice. I could use 2% of your first million. db Well, It's not a bad idea ! I'll forward that question off to Robin. I have ran into several that use separate and independent battery banks and switch between them. I'm not sure why they don't just use those L-16 size 2V cells though instead. But as I mentioned before, I think that a battery balancer device would take care of problems with single strings but maybe even parallel strings, as well as the pesky problem of AGM batteries that like to plump when you cook 'em ! (I hate when that happens and one battery gets real hot) Say, maybe a gizmo that goes across each battery (no 2V cells though) to keep each battery in the string at the same voltage. It would have to be cheap, maybe $30. Great discussion. boB Dan Brown Foxfire Energy Corp. Renewable Energy Systems (802)-483-2564 www.Foxfire-Energy.com http://www.Foxfire-Energy.com NABCEP #092907-44 Original Message Subject: Re: [RE-wrenches] 24 volt Battery Bank comparison From: boB Gudgel b...@midnitesolar.com mailto:b...@midnitesolar.com Date: Thu, June 02, 2011 8:56 pm To: RE-wrenches re-wrenches@lists.re-wrenches.org mailto:re-wrenches@lists.re-wrenches.org Nobody mentioned this in this thread, but it occurs to me that the answer may be made clearer by looking at the Voc of each battery string after so many Amp-Hours (years) of service. i.e., disconnect the strings' parallel connection and measure the individual string voltage after charging them all the best that can be done. This would be making the assumption that the batteries themselves were fairly equal capacity and voltage at installation time. And for whatever reasons, connections, temperatures and everything else discussed here, the strings degrade differently. The older and more worn out batteries should have a lower voltage (Voc) than the less worn out strings. Thus, the better strings may be tending to hold up the worse strings by dumping charge into them when the whole bank is discharging, and wasting energy and battery efficiency. I guess that just large 2V cells are the answer in this case, if at all possible. Thanks for the help on this question ! boB On 6/2/2011 10:42 AM, Tom Elliot wrote: Not surprised at all about the phone company guy. It was a phone company guy who read me the riot act that no one in their right minds would ever parallel battery banks the way PV off-grid systems did and got me to set up my system with separate strings connected independently to buss bars. The battery engineer I talked to years ago at Dynasty not only said the same thing but also said keeping strings separate meant individual string distance from the bars became irrelevant (given correctly sized wire for each string’s parallel connectors). I had a system with 12 100 amphour strings of paired 12v Dynasty AGMs which was rock solid until the day I sold the house. The last time I checked the system before the sale no single battery varied from any other in the system by more than 1/10 volt and the majority were still holding identical voltages. *From:* d...@foxfire-energy.com mailto:d...@foxfire-energy.com *Sent:* Wednesday, June 01, 2011 4:14 PM *To:* RE-wrenches mailto:re-wrenches@lists.re-wrenches.org *Subject:* Re: [RE-wrenches] 24 volt Battery Bank comparison Good thread. Thanks. In my experience, it all boils down to the customer. I've seen one temp. set up with like 12 strings (for a concert). but they were recharged and sold individually within a few weeks.. I've also seen a single string (Teledyne aircraft batteries) fail in less than a year.. they were in a brand new airplane tug that was never charged -- ever. (the guy said I dunno, it just stopped working). I have one customer who (last I knew) was running 6 strings of mixed aged L-16s going on 8 years. Thing is, he's a retired phone company dude (Who's missing half of his right hand from using one of those pocket pal screwdriver thingys on a key
Re: [RE-wrenches] 24 volt Battery Bank comparison
boB, If you build it, it will sell. I’d love to see a battery distribution box, with separate fusing and disconnects, and maybe shunts, for each string, with large bus bars in it and enclosed in a corrosion resistant box. Oh…and Listed. It would need to come in a variety of sizes, like 250A, 500A, 1000A, and also maybe able to be daisy-chained for really large systems, like up to 100kW at 48VDC Hint..hint… Brian Teitelbaum AEE Solar From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of boB Gudgel Sent: Thursday, June 02, 2011 8:50 PM To: RE-wrenches Subject: Re: [RE-wrenches] 24 volt Battery Bank comparison On 6/2/2011 6:44 PM, d...@foxfire-energy.commailto:d...@foxfire-energy.com wrote: What I like best about Mark's set up (the retired phone co. dude w/ half a hand), is that he can select individual strings at random. he can eq an individual string, or top off a few strings and park them. he can even run strings of T 105s, or even nicad (individually of course) in the same system as L-16s and the like.. he just reprograms the chargers (and logs it). I think he got the design from his days in the Navy. So boB, how about a controller that can be user programed to charge multiple battery configurations with a soft switch? i.e. Bank A, Bank B...? and while you're at it, maybe a multiple string DC box? Something with a shunt and a breaker for each string? A four string set up would be nice. I could use 2% of your first million. db Well, It's not a bad idea ! I'll forward that question off to Robin. I have ran into several that use separate and independent battery banks and switch between them. I'm not sure why they don't just use those L-16 size 2V cells though instead. But as I mentioned before, I think that a battery balancer device would take care of problems with single strings but maybe even parallel strings, as well as the pesky problem of AGM batteries that like to plump when you cook 'em ! (I hate when that happens and one battery gets real hot) Say, maybe a gizmo that goes across each battery (no 2V cells though) to keep each battery in the string at the same voltage. It would have to be cheap, maybe $30. Great discussion. boB Dan Brown Foxfire Energy Corp. Renewable Energy Systems (802)-483-2564 www.Foxfire-Energy.comhttp://www.Foxfire-Energy.com NABCEP #092907-44 Original Message Subject: Re: [RE-wrenches] 24 volt Battery Bank comparison From: boB Gudgel b...@midnitesolar.commailto:b...@midnitesolar.com Date: Thu, June 02, 2011 8:56 pm To: RE-wrenches re-wrenches@lists.re-wrenches.orgmailto:re-wrenches@lists.re-wrenches.org Nobody mentioned this in this thread, but it occurs to me that the answer may be made clearer by looking at the Voc of each battery string after so many Amp-Hours (years) of service. i.e., disconnect the strings' parallel connection and measure the individual string voltage after charging them all the best that can be done. This would be making the assumption that the batteries themselves were fairly equal capacity and voltage at installation time. And for whatever reasons, connections, temperatures and everything else discussed here, the strings degrade differently. The older and more worn out batteries should have a lower voltage (Voc) than the less worn out strings. Thus, the better strings may be tending to hold up the worse strings by dumping charge into them when the whole bank is discharging, and wasting energy and battery efficiency. I guess that just large 2V cells are the answer in this case, if at all possible. Thanks for the help on this question ! boB On 6/2/2011 10:42 AM, Tom Elliot wrote: Not surprised at all about the phone company guy. It was a phone company guy who read me the riot act that no one in their right minds would ever parallel battery banks the way PV off-grid systems did and got me to set up my system with separate strings connected independently to buss bars. The battery engineer I talked to years ago at Dynasty not only said the same thing but also said keeping strings separate meant individual string distance from the bars became irrelevant (given correctly sized wire for each string’s parallel connectors). I had a system with 12 100 amphour strings of paired 12v Dynasty AGMs which was rock solid until the day I sold the house. The last time I checked the system before the sale no single battery varied from any other in the system by more than 1/10 volt and the majority were still holding identical voltages. From: d...@foxfire-energy.commailto:d...@foxfire-energy.com Sent: Wednesday, June 01, 2011 4:14 PM To: RE-wrenchesmailto:re-wrenches@lists.re-wrenches.org Subject: Re: [RE-wrenches] 24 volt Battery Bank comparison Good thread. Thanks. In my experience, it all boils down to the customer. I've seen one temp. set up with like 12 strings (for a concert). but they were recharged
Re: [RE-wrenches] 24 volt Battery Bank comparison
OK, I've been hearing for years now that one battery string is best and maybe two but no more should be used. What is the reason for this fear ???What is the experience with multiple strings in parallel ?? If it is because of current sharing of the strings, that shouldn't be an insurmountable problem if the wiring is done right. If it has to do with the possibility of fire, which Darryl mentioned, seems that series string fuses could mitigate the possibility of that issue, if because of shorted cells, just like PV combiners. Or maybe it has to do with the trouble of getting into the middle of a pile of batteries ? Use battery boxes ? The strings are in parallel and so they all get the same voltage, theoretically anyway if the connections are good. I would think that the more strings, the LESS stress on individual batteries, not more. The current in each battery should be less than it would be I would think. So what is the real experience ?? Is a battery balancer the answer ?? Thanks, boB On May 31, 2011, at 8:23 PM, Wayne Irwin wa...@pureenergysolar.com mailto:wa...@pureenergysolar.com wrote: I think the verdict is*12* - Rolls 2-YS-31 2430 AH @ 20 HR (one string) and one dry spare in storage is the best case scenario! Wayne Irwin, EE Director of Engineering Pure Energy Solar International Inc. State Licensed Solar Contractor License # CVC56695 wa...@pureenergysolar.com mailto:wa...@pureenergysolar.com http://pureenergysolar.com 352 377-6527 Office 352 336-3299 Fax 352 316-1637 Cell ___ 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 volt Battery Bank comparison
On 5/31/2011 11:25 PM, Tom Elliot wrote: Bob, I totally understand the concern about multiple strings *if the strings are connected across the battery bank* as had always been the tradition in off-grid installations. My own experience with such a bank in my system showed why when I had a single cell get to near meltdown. I was lucky to find it. This might be a good reason for an installer to have one of those FLIR (or similar) thermal imager cameras. They're a bit on the expensive side, but could really be helpful for so many things. Even just to know if you have left a nut loose (under load of course) boB Maintenance is another reason, such banks are far more difficult to maintain. But I think those concerns are ameliorated a great deal with a buss bar installation and once I did that I never had another problem and found the battery bank much easier to maintain because the strings no longer had to be right next to each other. Heck, it would be possible to put each series string in its own box for that matter. And with the inclusion of string fuses that reduces problems even further. When living with an off-grid system my biggest concern was system reliability and redundancy and the idea of a single string failure was a big worry which is why I never would consider it. Tom *From:* boB Gudgel mailto:b...@midnitesolar.com *Sent:* Tuesday, May 31, 2011 8:16 PM *To:* RE-wrenches mailto:re-wrenches@lists.re-wrenches.org *Subject:* Re: [RE-wrenches] 24 volt Battery Bank comparison OK, I've been hearing for years now that one battery string is best and maybe two but no more should be used. What is the reason for this fear ???What is the experience with multiple strings in parallel ?? If it is because of current sharing of the strings, that shouldn't be an insurmountable problem if the wiring is done right. If it has to do with the possibility of fire, which Darryl mentioned, seems that series string fuses could mitigate the possibility of that issue, if because of shorted cells, just like PV combiners. Or maybe it has to do with the trouble of getting into the middle of a pile of batteries ? Use battery boxes ? The strings are in parallel and so they all get the same voltage, theoretically anyway if the connections are good. I would think that the more strings, the LESS stress on individual batteries, not more. The current in each battery should be less than it would be I would think. So what is the real experience ?? Is a battery balancer the answer ?? Thanks, boB On May 31, 2011, at 8:23 PM, Wayne Irwin wa...@pureenergysolar.com mailto:wa...@pureenergysolar.com wrote: I think the verdict is*12* - Rolls 2-YS-31 2430 AH @ 20 HR (one string) and one dry spare in storage is the best case scenario! Wayne Irwin, EE Director of Engineering Pure Energy Solar International Inc. State Licensed Solar Contractor License # CVC56695 wa...@pureenergysolar.com mailto:wa...@pureenergysolar.com http://pureenergysolar.com 352 377-6527 Office 352 336-3299 Fax 352 316-1637 Cell ___ 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 http://www.avg.com Version: 10.0.1375 / Virus Database: 1511/3672 - Release Date: 05/31/11 ___ 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 volt Battery Bank comparison
If one cell gets a higher internal loss than the others is hogs the charging current and will over charge its string partners. It is a problem of the temperature of all cells in all parallel strings having the same thermal environment, so they all have the same voltage. (the case of one of 4 parallel strings in battery house, big system, the string near the outside south wall caught fire) In particular this is a problem of AGMs, a recent east cost problem where batteries had been in business for 2 yrs and for some reason the battery room erupted with one of 5 strings in thermal runaway. this is the same as trying to put bipolar transistors in parallel. I reciently had 8 parallel strings not of my choice, advised customer of potential hazard, used Midnight combiner with 30 amp breakers on each string, so far it is OK but this is playing with fire. Hopfully if one string goes bad in thermal runaway it will trip the breaker feeding that string. . From: boB Gudgel b...@midnitesolar.com To: RE-wrenches re-wrenches@lists.re-wrenches.org Sent: Wednesday, June 1, 2011 1:16 AM Subject: Re: [RE-wrenches] 24 volt Battery Bank comparison OK, I've been hearing for years now that one battery string is best and maybe two but no more should be used. What is the reason for this fear ??? What is the experience with multiple strings in parallel ?? If it is because of current sharing of the strings, that shouldn't be an insurmountable problem if the wiring is done right. If it has to do with the possibility of fire, which Darryl mentioned, seems that series string fuses could mitigate the possibility of that issue, if because of shorted cells, just like PV combiners. Or maybe it has to do with the trouble of getting into the middle of a pile of batteries ? Use battery boxes ? The strings are in parallel and so they all get the same voltage, theoretically anyway if the connections are good. I would think that the more strings, the LESS stress on individual batteries, not more. The current in each battery should be less than it would be I would think. So what is the real experience ?? Is a battery balancer the answer ?? Thanks, boB On May 31, 2011, at 8:23 PM, Wayne Irwin wa...@pureenergysolar.com wrote: I think the verdict is12 - Rolls 2-YS-31 2430 AH @ 20 HR (one string) and one dry spare in storage is the best case scenario! Wayne Irwin, EE Director of Engineering Pure Energy Solar International Inc. State Licensed Solar Contractor License # CVC56695 wa...@pureenergysolar.com http://pureenergysolar.com 352 377-6527 Office 352 336-3299 Fax 352 316-1637 Cell ___ 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 volt Battery Bank comparison
Hi Michael, With all due respect, do the reference idiot lights do that much for you? I have always thought a thermal camera/viewer/FLIR/etc. would be great but so would a used car. My digital IR thermometer at several orders of magnitude difference in price has served me well, if tediously, to do some of the uses described. Bill Loesch Solar 1 - Saint Louis Solar 314 631 1094 - Original Message - From: Michael Welch michael.we...@re-wrenches.org To: RE-wrenches re-wrenches@lists.re-wrenches.org Sent: Wednesday, June 01, 2011 12:43 PM Subject: Re: [RE-wrenches] 24 volt Battery Bank comparison Every now and then I see reference on this list to the need for thermal detection. Here is an interesting, inexpensive piece of equipment that could be used for finding hot (loose or corroded) connections, hot batteries, hot PV cells in modules, and even poorly insulated spots, its original intended purpose: http://www.blackanddecker.com/power-tools/TLD100.aspx I have one and used it for finding uninsulated spaces, but cannot attest to its durability or suitability for the other uses mentioned above. boB Gudgel wrote at 01:00 AM 6/1/2011: This might be a good reason for an installer to have one of those FLIR (or similar) thermal imager cameras.  They're a bit on the expensive side, but could really be helpful for so many things.  Even just to know if you have left a nut loose (under load of course) boB ___ 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 volt Battery Bank comparison, Why a single string?
On 6/1/2011 8:41 AM, Larry Crutcher, Starlight Solar Power Systems wrote: Hi boB, We know that current will flow through the lowest resistive path. In a perfect world, the resistance from end to end of a battery string will be identical. Real world conditions show that one or more cells have a slightly higher internal resistance. Add to that the imperfect terminal crimp, improper torque at battery terminal, and perhaps terminal corrosion and we now have paths of differing resistance. The parallel strings have an unequal distribution of current and ergo undercharged cells. These cells retain a small amount of amorphous lead sulphate that, without correction, will begin to crystalize. We all know what will happen over time. The issue of maintenance is a not brainer of course... i.e. the need to add water... Imperfect crimps would be a problem with a single string of batteries too. If the resistance is higher in that cell in the one string, then yes, that one string will not be working nearly as hard as the other strings. Bad workmanship is not an excuse for not using multiple strings as far as I know. If one string is discharged more than another parallel string, then its finishing (ending) Amps will will certainly happen later than a string that wasn't discharged as deep, but if using a timed Absorb cycle, why does this matter ?? They're all receiving the same voltage and should be treated the same in that case. Right ??At least for timed charging cycles. As Darryl pointed out, AGMs like to get hot when unbalanced and this is definitely what I have seen. But that again can happen for a single string rather than multiple strings. One thing that hasn't been mentioned, unless I missed it, is the possibility that a shorted cell in one string can drag down the other strings it is in parallel with. The more strings in parallel, statistically, there would be more of a chance for that to happen. That would be more of a self discharge issue I would think which isn't good. boB Granted, this can be prevented by the proper knowledge and attention but I see far too many failures from neglect and/or lack of understanding. My experience comes from 10 years of working with hundreds of small 12 volt systems with 2 to 6 parallel strings of batteries. In our shop we often see 2 to 3 year old battery banks that are damaged and I believe this is a contributing factor. It is often too late by the time the problem is discovered. So, my opinion is to reduce this possibility by decreasing the parallel paths whenever possible. More strings of a given size battery means less stress per string. But, if you decrease strings you are normally increasing cell size to maintain the capacity so this should not be an issue. Battery balancing is a great idea. I would like to see an active system for shunting current on a string to keep an equal current across all strings. I know this is done in the EV business. Larry Crutcher Starlight Solar Power Systems 11871 S Fortuna Road, #210 Yuma, AZ 85367 la...@starlightsolar.com mailto:la...@starlightsolar.com (928) 342-9103 On May 31, 2011, at 11:16 PM, boB Gudgel wrote: OK, I've been hearing for years now that one battery string is best and maybe two but no more should be used. What is the reason for this fear ???What is the experience with multiple strings in parallel ?? If it is because of current sharing of the strings, that shouldn't be an insurmountable problem if the wiring is done right. If it has to do with the possibility of fire, which Darryl mentioned, seems that series string fuses could mitigate the possibility of that issue, if because of shorted cells, just like PV combiners. Or maybe it has to do with the trouble of getting into the middle of a pile of batteries ? Use battery boxes ? The strings are in parallel and so they all get the same voltage, theoretically anyway if the connections are good. I would think that the more strings, the LESS stress on individual batteries, not more. The current in each battery should be less than it would be I would think. So what is the real experience ?? Is a battery balancer the answer ?? Thanks, boB ___ 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
Re: [RE-wrenches] 24 volt Battery Bank comparison
On 6/1/2011 10:43 AM, Michael Welch wrote: Every now and then I see reference on this list to the need for thermal detection. Here is an interesting, inexpensive piece of equipment that could be used for finding hot (loose or corroded) connections, hot batteries, hot PV cells in modules, and even poorly insulated spots, its original intended purpose: http://www.blackanddecker.com/power-tools/TLD100.aspx I have one and used it for finding uninsulated spaces, but cannot attest to its durability or suitability for the other uses mentioned above. Yep. These are very handy indeed ! AND they're cheap ! But these types are quite different from what I was talking about when I mentioned the very pricey thermal imagers like FLIRs. For the single point thermometers like the BD device, you must run it over EVERY single spot that you want to check for heat. Batteries, Connections, Cables and each one individually. With something like the FLIR you can just hold it and stand in one place and it will show you where any hot spots (or cold spots) are AND give you the temperature. That is, if the emissivity is close enough, but you can still see if something is really hot with the imager. I just wish they were cheaper ! boB boB Gudgel wrote at 01:00 AM 6/1/2011: This might be a good reason for an installer to have one of those FLIR (or similar) thermal imager cameras.  They're a bit on the expensive side, but could really be helpful for so many things.  Even just to know if you have left a nut loose (under load of course) boB ___ 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 volt Battery Bank comparison
I recently purchased one and it has been useful. It can also be used to find poorly insulated buildings, air leaks etc. I have been told that in some states, fire departments will make their thermal imaging cameras available to qualified people for conducting these types of surveys. Chris On 6/1/2011 1:43 PM, Michael Welch wrote: Every now and then I see reference on this list to the need for thermal detection. Here is an interesting, inexpensive piece of equipment that could be used for finding hot (loose or corroded) connections, hot batteries, hot PV cells in modules, and even poorly insulated spots, its original intended purpose: http://www.blackanddecker.com/power-tools/TLD100.aspx I have one and used it for finding uninsulated spaces, but cannot attest to its durability or suitability for the other uses mentioned above. boB Gudgel wrote at 01:00 AM 6/1/2011: This might be a good reason for an installer to have one of those FLIR (or similar) thermal imager cameras.  They're a bit on the expensive side, but could really be helpful for so many things.  Even just to know if you have left a nut loose (under load of course) boB ___ 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 -- Christopher Warfel, P.E. ENTECH Engineering, Inc. Energy Utilization Experts (401)466-8978 The information contained within this communication shall be considered confidential and shall not be retransmitted without knowledge of the sender. Please contact us if this email reached you in error. Thank you. ___ 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 volt Battery Bank comparison
Good thread. Thanks. In my experience, it all boils down to the customer. I've seen one temp. set up with like 12 strings (for a concert). but they were recharged and sold individually within a few weeks.. I've also seen a single string (Teledyne aircraft batteries) fail in less than a year.. they were in a brand new airplane tug that was never charged -- ever. (the guy said "I dunno, it just stopped working"). I have one customer who (last I knew) was running 6 strings of mixed aged L-16s going on 8 years. Thing is, he's a retired phone company dude (Who's missing half of his right hand from using one of those pocket pal screwdriver thingys on a key chain in a hot DC rack.. like he'd done hundreds of times before.. but that's another tale). But I do like his set up.. he has each string set up with it's own fused Disco and Trimetric.. Gives him random control over each string. And yes, he keeps a very detailed log, and you can bet that when he takes a battery out of service, it's done. Me? for an average bullet proof off grid system, I shoot for a max of two strings for 24V systems (for the redundancy), and manually reconfigure them every few years. for 48V systems, I shoot for one string of two Volt cells.. thinking that if I loose a cell I can still operate a 46V system until I get a replacement. And Yes, as we all know, there are folks out there that really shouldn't be allowed to operate a popsicle stick. dbDan BrownFoxfire Energy Corp.Renewable Energy Systems(802)-483-2564www.Foxfire-Energy.comNABCEP #092907-44 Original Message Subject: Re: [RE-wrenches] 24 volt Battery Bank comparison From: Michael Welch michael.we...@re-wrenches.org Date: Wed, June 01, 2011 1:43 pm To: RE-wrenches re-wrenches@lists.re-wrenches.org Every now and then I see reference on this list to the need for thermal detection. Here is an interesting, inexpensive piece of equipment that could be used for finding hot (loose or corroded) connections, hot batteries, hot PV cells in modules, and even poorly insulated spots, its original intended purpose: http://www.blackanddecker.com/power-tools/TLD100.aspx I have one and used it for finding uninsulated spaces, but cannot attest to its durability or suitability for the other uses mentioned above. boB Gudgel wrote at 01:00 AM 6/1/2011: This might be a good reason for an installer to have one of those FLIR (or similar) thermal imager cameras.  They're a bit on the expensive side, but could really be helpful for so many things.  Even just to know if you have left a nut loose (under load of course) boB ___ 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 volt Battery Bank comparison
any things. Even just to know if
you have left a nut loose (under load of course)
boB
Maintenance
is another reason, such banks are far more difficult
to maintain. But I think those concerns are
ameliorated a great deal with a buss bar
installation and once I did that I never had another
problem and found the battery bank much easier to
maintain because the strings no longer had to be
right next to each other. Heck, it would be
possible to put each series string in its own box
for that matter. And with the inclusion of string
fuses that reduces problems even further.
When
living with an off-grid system my biggest concern
was system reliability and redundancy and the idea
of a single string failure was a big worry which is
why I never would consider it.
Tom
From:
boB
Gudgel
Sent:
Tuesday, May 31, 2011 8:16 PM
To:
RE-wrenches
Subject:
Re: [RE-wrenches] 24 volt Battery Bank
comparison
OK, I've been hearing for years now that one battery
string is best and maybe two but no more should be
used.
What is the reason for this fear ??? What is the
experience with multiple strings in parallel ??
If it is because of current sharing of the strings,
that shouldn't be an insurmountable problem if the
wiring is done right.
If it has to do with the possibility of fire, which
Darryl mentioned, seems that series string fuses
could mitigate the possibility of that issue, if
because of shorted cells, just like PV combiners.
Or maybe it has to do with the trouble of getting
into the middle of a pile of batteries ? Use
battery boxes ?
The strings are in parallel and so they all get the
same voltage, theoretically anyway if the
connections are good.
I would think that the more strings, the LESS stress
on individual batteries, not more. The current in
each battery should be less than it would be I would
think.
So what is the real experience ??
Is a battery balancer the answer ??
Thanks,
boB
On May 31, 2011, at 8:23 PM, "Wayne Irwin" wa...@pureenergysolar.com
wrote:
I
think the verdict is 12 -
Rolls 2-YS-31 2430 AH @ 20 HR (one string) and
one dry spare in storage is the best case
scenario!
Wayne
Irwin, EE
Director of Engineering
[RE-wrenches] 24 volt Battery Bank comparison
Hello Esteemed Battery Gurus, Which of the following do you believe is the better 24 V battery bank? A) 13 - Rolls 2-YS-31 2430 AH @ 20 HR (one string) or B) 9 - Rolls 8-CS-25P 820 AH @ 20 HR (3 strings of 3) Thank you in advance for your input! Wayne Irwin, EE Director of Engineering Pure Energy Solar International Inc. State Licensed Solar Contractor License # CVC56695 wa...@pureenergysolar.com http://pureenergysolar.com 352 377-6527 Office 352 336-3299 Fax 352 316-1637 Cell The content of this message is Pure Energy Solar Confidential. If you are not the intended recipient and have received this message in error, any use or distribution is prohibited. Please notify me immediately by reply e-mail and delete this message from your computer system. Thank you. ___ 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 volt Battery Bank comparison
Hi Wayne, I look forward to the input from the wrenches. My recommendation, regardless of the brand, would be for one string. Regards, Jamie Wayne Irwin wa...@pureenergysolar.com 5/31/2011 6:49 PM Hello Esteemed Battery Gurus, Which of the following do you believe is the better 24 V battery bank? A) 13 - Rolls 2-YS-31 2430 AH @ 20 HR (one string) or B) 9 - Rolls 8-CS-25P 820 AH @ 20 HR (3 strings of 3) Thank you in advance for your input! Wayne Irwin, EE Director of Engineering Pure Energy Solar International Inc. State Licensed Solar Contractor License # CVC56695 wa...@pureenergysolar.com ( mailto:pureenergyso...@hotmail.com ) http://pureenergysolar.com ( http://pureenergysolar.net/ ) 352 377-6527 Office 352 336-3299 Fax 352 316-1637 Cell The content of this message is Pure Energy Solar Confidential. If you are not the intended recipient and have received this message in error, any use or distribution is prohibited. Please notify me immediately by reply e-mail and delete this message from your computer system. Thank you. This email and its attachments have been scanned by iConnection E-Mail Firewall for viruses, spam, and malicious content. The information transmitted in this email is intended only for the entity or person to which it is addressed and may contain confidential/privileged material. If you received this in error, please contact the sender and delete the material from any computer. Any review, retransmission, dissemination, or other use of this information by persons or entities other than the intended recipient is strictly prohibited. %^^% ___ 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 volt Battery Bank comparison
Hi Wayne- While I think a lot of folks will agree that a single string is better for the long term health of the batteries as it results in more even charging, I still like the idea of at least two strings. That way if a single battery fails, that string can be removed and the end-user can at least get by on half of the pack until a replacement can be installed. Brian On Tue, May 31, 2011 at 10:19 PM, James Surrette ja...@surrette.com wrote: Hi Wayne, I look forward to the input from the wrenches. My recommendation, regardless of the brand, would be for one string. Regards, Jamie Wayne Irwin wa...@pureenergysolar.com 5/31/2011 6:49 PM Hello Esteemed Battery Gurus, Which of the following do you believe is the better 24 V battery bank? A) 13 - Rolls 2-YS-31 2430 AH @ 20 HR (one string) or B) 9 - Rolls 8-CS-25P 820 AH @ 20 HR (3 strings of 3) Thank you in advance for your input! Wayne Irwin, EE Director of Engineering Pure Energy Solar International Inc. State Licensed Solar Contractor License # CVC56695 wa...@pureenergysolar.com pureenergyso...@hotmail.com http://pureenergysolar.com http://pureenergysolar.net/ 352 377-6527 Office 352 336-3299 Fax 352 316-1637 Cell The content of this message is Pure Energy Solar Confidential. If you are not the intended recipient and have received this message in error, any use or distribution is prohibited. Please notify me immediately by reply e-mail and delete this message from your computer system. Thank you. This email and its attachments have been scanned by iConnection E-Mail Firewall for viruses, spam, and malicious content. The information transmitted in this email is intended only for the entity or person to which it is addressed and may contain confidential/privileged material. If you received this in error, please contact the sender and delete the material from any computer. Any review, retransmission, dissemination, or other use of this information by persons or entities other than the intended recipient is strictly prohibited. %^^% ___ 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 -- Brian Mehalic NABCEP Certified Solar PV Installer™ R031508-59 IREC ISPQ Certified Affiliated Instructor/PV US-0132 PV Curriculum Developer and Instructor Solar Energy International Carbondale, CO 81623 http://www.solarenergy.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 volt Battery Bank comparison
My one string of 1476 AH IBE 2 V cells went 19 years before retiring them to a neighbor's off grid system, where they are now working. One string has my vote! Sincerely, Chris Worcester Solar Wind Works NABCEP Certified PV Installer Phone: 530-582-4503 Fax: 530-582-4603 www.solarwindworks.com http://www.solarwindworks.com/ ch...@solarwindworks.com Proven Energy Solutions From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Brian Mehalic Sent: Tuesday, May 31, 2011 3:25 PM To: RE-wrenches Subject: Re: [RE-wrenches] 24 volt Battery Bank comparison Hi Wayne- While I think a lot of folks will agree that a single string is better for the long term health of the batteries as it results in more even charging, I still like the idea of at least two strings. That way if a single battery fails, that string can be removed and the end-user can at least get by on half of the pack until a replacement can be installed. Brian On Tue, May 31, 2011 at 10:19 PM, James Surrette ja...@surrette.com wrote: Hi Wayne, I look forward to the input from the wrenches. My recommendation, regardless of the brand, would be for one string. Regards, Jamie Wayne Irwin wa...@pureenergysolar.com 5/31/2011 6:49 PM Hello Esteemed Battery Gurus, Which of the following do you believe is the better 24 V battery bank? A) 13 - Rolls 2-YS-31 2430 AH @ 20 HR (one string) or B) 9 - Rolls 8-CS-25P 820 AH @ 20 HR (3 strings of 3) Thank you in advance for your input! Wayne Irwin, EE Director of Engineering Pure Energy Solar International Inc. State Licensed Solar Contractor License # CVC56695 wa...@pureenergysolar.com mailto:pureenergyso...@hotmail.com http://pureenergysolar.com http://pureenergysolar.net/ 352 377-6527 Office 352 336-3299 Fax 352 316-1637 Cell The content of this message is Pure Energy Solar Confidential. If you are not the intended recipient and have received this message in error, any use or distribution is prohibited. Please notify me immediately by reply e-mail and delete this message from your computer system. Thank you. This email and its attachments have been scanned by iConnection E-Mail Firewall for viruses, spam, and malicious content. The information transmitted in this email is intended only for the entity or person to which it is addressed and may contain confidential/privileged material. If you received this in error, please contact the sender and delete the material from any computer. Any review, retransmission, dissemination, or other use of this information by persons or entities other than the intended recipient is strictly prohibited. %^^% ___ 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 -- Brian Mehalic NABCEP Certified Solar PV InstallerT R031508-59 IREC ISPQ Certified Affiliated Instructor/PV US-0132 PV Curriculum Developer and Instructor Solar Energy International Carbondale, CO 81623 http://www.solarenergy.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 volt Battery Bank comparison
Wayne, First, let's hope you mean 12 of the 2YS31. A single battery string is always preferable to multiple strings in my book. The only downside is interconnect cables the same size as your inverter cables. That probably means 4/0 CU for most 24V, 3KW and up inverters. Two strings in parallel-not too bad. Three strings- as far as you want to push it. More strings- Don't go there. Bob-O On May 31, 2011, at 2:49 PM, Wayne Irwin wrote: Hello Esteemed Battery Gurus, Which of the following do you believe is the better 24 V battery bank? A) 13 - Rolls 2-YS-31 2430 AH @ 20 HR (one string) or B) 9 - Rolls 8-CS-25P 820 AH @ 20 HR (3 strings of 3) Thank you in advance for your input! Wayne Irwin, EE Director of Engineering Pure Energy Solar International Inc. State Licensed Solar Contractor License # CVC56695 wa...@pureenergysolar.com http://pureenergysolar.com 352 377-6527 Office 352 336-3299 Fax 352 316-1637 Cell The content of this message is Pure Energy Solar Confidential. If you are not the intended recipient and have received this message in error, any use or distribution is prohibited. Please notify me immediately by reply e-mail and delete this message from your computer system. Thank you.___ 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 volt Battery Bank comparison
Fewer number of strings the better. Go with plan A. Why 13 (and not 12) of the Rolls if I may ask? Peter T. Parrish, Ph.D., President California Solar Engineering, Inc. 820 Cynthia Ave., Los Angeles, CA 90065 CA Lic. 854779, NABCEP Cert. 031806-26 peter.parr...@calsolareng.com Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885 From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Wayne Irwin Sent: Tuesday, May 31, 2011 2:50 PM To: Wrenches Subject: [RE-wrenches] 24 volt Battery Bank comparison Hello Esteemed Battery Gurus, Which of the following do you believe is the better 24 V battery bank? A) 13 - Rolls 2-YS-31 2430 AH @ 20 HR (one string) or B) 9 - Rolls 8-CS-25P 820 AH @ 20 HR (3 strings of 3) Thank you in advance for your input! Wayne Irwin, EE Director of Engineering Pure Energy Solar International Inc. State Licensed Solar Contractor License # CVC56695 wa...@pureenergysolar.com http://pureenergysolar.com 352 377-6527 Office 352 336-3299 Fax 352 316-1637 Cell The content of this message is Pure Energy Solar Confidential. If you are not the intended recipient and have received this message in error, any use or distribution is prohibited. Please notify me immediately by reply e-mail and delete this message from your computer system. Thank you. ___ 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 volt Battery Bank comparison
From a reliability standpoint I would never want to bet the farm on one string. All it takes is the failure of one cell and the system is useless until it is replaced. Three strings means a cell failure only reduces capacity by 33% not 100%. I’ve always thought in off-grid systems it is a good idea to build in as much redundancy as possible whenever possible. Oh, and always use a buss bar system with multiple strings, it makes for a far more stable system with less stress on the batteries. Tom From: Wayne Irwin Sent: Tuesday, May 31, 2011 11:49 AM To: Wrenches Subject: [RE-wrenches] 24 volt Battery Bank comparison Hello Esteemed Battery Gurus, Which of the following do you believe is the better 24 V battery bank? A) 13 - Rolls 2-YS-31 2430 AH @ 20 HR (one string) or B) 9 - Rolls 8-CS-25P 820 AH @ 20 HR (3 strings of 3) Thank you in advance for your input! Wayne Irwin, EE Director of Engineering Pure Energy Solar International Inc. State Licensed Solar Contractor License # CVC56695 mailto:pureenergyso...@hotmail.com http://pureenergysolar.com 352 377-6527 Office 352 336-3299 Fax 352 316-1637 Cell The content of this message is Pure Energy Solar Confidential. If you are not the intended recipient and have received this message in error, any use or distribution is prohibited. Please notify me immediately by reply e-mail and delete this message from your computer system. Thank you. ___ 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: 10.0.1375 / Virus Database: 1509/3671 - Release Date: 05/31/11 ___ 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 volt Battery Bank comparison
Hello all. I am indeed thinking of 13 - 2 volt batteries to make up a 26 volt battery bank for the 24 volt system. Thoughts for or against are welcome. Wayne Irwin, EE Director of Engineering Pure Energy Solar International Inc. State Licensed Solar Contractor License # CVC56695 wa...@pureenergysolar.com http://pureenergysolar.com 352 377-6527 Office 352 336-3299 Fax 352 316-1637 Cell The content of this message is Pure Energy Solar Confidential. If you are not the intended recipient and have received this message in error, any use or distribution is prohibited. Please notify me immediately by reply e-mail and delete this message from your computer system. Thank you. From: bo...@electronconnection.com Date: Tue, 31 May 2011 15:40:14 -0700 To: re-wrenches@lists.re-wrenches.org Subject: Re: [RE-wrenches] 24 volt Battery Bank comparison Wayne,First, let's hope you mean 12 of the 2YS31. A single battery string is always preferable to multiple strings in my book. The only downside is interconnect cables the same size as your inverter cables. That probably means 4/0 CU for most 24V, 3KW and up inverters. Two strings in parallel-not too bad. Three strings- as far as you want to push it. More strings- Don't go there.Bob-O On May 31, 2011, at 2:49 PM, Wayne Irwin wrote:Hello Esteemed Battery Gurus, Which of the following do you believe is the better 24 V battery bank? A) 13 - Rolls 2-YS-31 2430 AH @ 20 HR (one string) or B) 9 - Rolls 8-CS-25P 820 AH @ 20 HR (3 strings of 3) Thank you in advance for your input! Wayne Irwin, EE Director of Engineering Pure Energy Solar International Inc. State Licensed Solar Contractor License # CVC56695 wa...@pureenergysolar.com http://pureenergysolar.com 352 377-6527 Office 352 336-3299 Fax 352 316-1637 Cell The content of this message is Pure Energy Solar Confidential. If you are not the intended recipient and have received this message in error, any use or distribution is prohibited. Please notify me immediately by reply e-mail and delete this message from your computer system. Thank you. ___ 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 volt Battery Bank comparison
Just for a little extra. Wayne Irwin, EE Director of Engineering Pure Energy Solar International Inc. State Licensed Solar Contractor License # CVC56695 wa...@pureenergysolar.com http://pureenergysolar.com 352 377-6527 Office 352 336-3299 Fax 352 316-1637 Cell The content of this message is Pure Energy Solar Confidential. If you are not the intended recipient and have received this message in error, any use or distribution is prohibited. Please notify me immediately by reply e-mail and delete this message from your computer system. Thank you. From: peter.parr...@calsolareng.com To: re-wrenches@lists.re-wrenches.org Date: Tue, 31 May 2011 16:05:06 -0700 Subject: Re: [RE-wrenches] 24 volt Battery Bank comparison Fewer number of strings the better. Go with plan A. Why 13 (and not 12) of the Rolls if I may ask? Peter T. Parrish, Ph.D., President California Solar Engineering, Inc. 820 Cynthia Ave., Los Angeles, CA 90065 CA Lic. 854779, NABCEP Cert. 031806-26 peter.parr...@calsolareng.com Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885 From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Wayne Irwin Sent: Tuesday, May 31, 2011 2:50 PM To: Wrenches Subject: [RE-wrenches] 24 volt Battery Bank comparison Hello Esteemed Battery Gurus, Which of the following do you believe is the better 24 V battery bank? A) 13 - Rolls 2-YS-31 2430 AH @ 20 HR (one string) or B) 9 - Rolls 8-CS-25P 820 AH @ 20 HR (3 strings of 3) Thank you in advance for your input! Wayne Irwin, EE Director of Engineering Pure Energy Solar International Inc. State Licensed Solar Contractor License # CVC56695 wa...@pureenergysolar.com http://pureenergysolar.com 352 377-6527 Office 352 336-3299 Fax 352 316-1637 Cell The content of this message is Pure Energy Solar Confidential. If you are not the intended recipient and have received this message in error, any use or distribution is prohibited. Please notify me immediately by reply e-mail and delete this message from your computer system. Thank you. ___ 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 volt Battery Bank comparison
If the choice is one or three, I choose one. If the choice is one or two, I choose two for the same redundancy benefit echoed by others. However, it sometimes depends how remote the system is. If you are a few miles down the road from a stocking battery distributor, one string is great. If you are a boat ride or a 10 hour 4x4 crawl at 2 mph away, redundancy may be critical. It all depends on the situation. I would even consider three strings if the location has serious access problems and the customer can only survive with 33% capacity loss for a period of time. While I have my favorite brands, sometimes you have to go with a brand that fits the right capacity and string arrangement. Fortunately Rolls has lots of options, so you should find a suitable alternative. I start with my desired V, aH, and parallel strings, then let the manufacturer or distributor do the work and recommend options. Not that I don't do my research, but sometimes they come up with a better option than you initially think of. Jason Szumlanski Fafco Solar On May 31, 2011, at 6:25 PM, Brian Mehalic br...@solarenergy.org wrote: Hi Wayne- While I think a lot of folks will agree that a single string is better for the long term health of the batteries as it results in more even charging, I still like the idea of at least two strings. That way if a single battery fails, that string can be removed and the end-user can at least get by on half of the pack until a replacement can be installed. Brian On Tue, May 31, 2011 at 10:19 PM, James Surrette ja...@surrette.com wrote: Hi Wayne, I look forward to the input from the wrenches. My recommendation, regardless of the brand, would be for one string. Regards, Jamie Wayne Irwin wa...@pureenergysolar.com 5/31/2011 6:49 PM Hello Esteemed Battery Gurus, Which of the following do you believe is the better 24 V battery bank? A) 13 - Rolls 2-YS-31 2430 AH @ 20 HR (one string) or B) 9 - Rolls 8-CS-25P 820 AH @ 20 HR (3 strings of 3) Thank you in advance for your input! Wayne Irwin, EE Director of Engineering Pure Energy Solar International Inc. State Licensed Solar Contractor License # CVC56695 wa...@pureenergysolar.com http://pureenergysolar.com 352 377-6527 Office 352 336-3299 Fax 352 316-1637 Cell The content of this message is Pure Energy Solar Confidential. If you are not the intended recipient and have received this message in error, any use or distribution is prohibited. Please notify me immediately by reply e-mail and delete this message from your computer system. Thank you. This email and its attachments have been scanned by iConnection E-Mail Firewall for viruses, spam, and malicious content. The information transmitted in this email is intended only for the entity or person to which it is addressed and may contain confidential/privileged material. If you received this in error, please contact the sender and delete the material from any computer. Any review, retransmission, dissemination, or other use of this information by persons or entities other than the intended recipient is strictly prohibited. %^^% ___ 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 -- Brian Mehalic NABCEP Certified Solar PV Installer™ R031508-59 IREC ISPQ Certified Affiliated Instructor/PV US-0132 PV Curriculum Developer and Instructor Solar Energy International Carbondale, CO 81623 http://www.solarenergy.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 ___ 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 volt Battery Bank comparison
Wayne, I'd recommend against that. To do an effective equalization charge on that bank you'll need to get the voltage up to at least 2.6-2.7V per cell. That would mean a 13 cell pack voltage of 34-35V. Got any DC loads at all? Danger, Will Robinson, Danger! Using the inverter as a charging source? I think you'll run out of transformer windings or at the very least reduce your amperage output greatly toward the end of that cycle. Hopefully, Jamie can jump in with an opinion here as well. Good Luck! Bob-O On May 31, 2011, at 4:28 PM, Wayne Irwin wrote: Just for a little extra. Wayne Irwin, EE Director of Engineering Pure Energy Solar International Inc. State Licensed Solar Contractor License # CVC56695 wa...@pureenergysolar.com http://pureenergysolar.com 352 377-6527 Office 352 336-3299 Fax 352 316-1637 Cell The content of this message is Pure Energy Solar Confidential. If you are not the intended recipient and have received this message in error, any use or distribution is prohibited. Please notify me immediately by reply e-mail and delete this message from your computer system. Thank you.___ 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 volt Battery Bank comparison
A) With a 13th battery and only one string, if there were a failure in one of the cells, the system would most likely demonstrate the failure rather quickly and allow for the faulty battery to be removed while still maintaining adequate voltage to operate the 24V system. B) On the other hand, Tom presents the exact reason behind the idea of the 3 - string design. This is an off grid system. I know this may open up a can of (philosophically varied) worms. But, this is the reasoning behind the two designs. PS. Buss bars (if 3 strings) and 4/0 CU would be used. Wayne Irwin, EE Director of Engineering Pure Energy Solar International Inc. State Licensed Solar Contractor License # CVC56695 wa...@pureenergysolar.com http://pureenergysolar.com 352 377-6527 Office 352 336-3299 Fax 352 316-1637 Cell The content of this message is Pure Energy Solar Confidential. If you are not the intended recipient and have received this message in error, any use or distribution is prohibited. Please notify me immediately by reply e-mail and delete this message from your computer system. Thank you. From: t...@wagonmaker.com To: re-wrenches@lists.re-wrenches.org Date: Tue, 31 May 2011 13:36:16 -1000 Subject: Re: [RE-wrenches] 24 volt Battery Bank comparison From a reliability standpoint I would never want to bet the farm on one string. All it takes is the failure of one cell and the system is useless until it is replaced. Three strings means a cell failure only reduces capacity by 33% not 100%. I’ve always thought in off-grid systems it is a good idea to build in as much redundancy as possible whenever possible. Oh, and always use a buss bar system with multiple strings, it makes for a far more stable system with less stress on the batteries. Tom From: Wayne Irwin Sent: Tuesday, May 31, 2011 11:49 AM To: Wrenches Subject: [RE-wrenches] 24 volt Battery Bank comparison Hello Esteemed Battery Gurus, Which of the following do you believe is the better 24 V battery bank? A) 13 - Rolls 2-YS-31 2430 AH @ 20 HR (one string) or B) 9 - Rolls 8-CS-25P 820 AH @ 20 HR (3 strings of 3) Thank you in advance for your input! Wayne Irwin, EE Director of Engineering Pure Energy Solar International Inc. State Licensed Solar Contractor License # CVC56695 mailto:pureenergyso...@hotmail.com http://pureenergysolar.com 352 377-6527 Office 352 336-3299 Fax 352 316-1637 Cell The content of this message is Pure Energy Solar Confidential. If you are not the intended recipient and have received this message in error, any use or distribution is prohibited. Please notify me immediately by reply e-mail and delete this message from your computer system. Thank you. ___ 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: 10.0.1375 / Virus Database: 1509/3671 - Release Date: 05/31/11 ___ 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 volt Battery Bank comparison
No DC loads at all. Wayne Irwin, EE Director of Engineering Pure Energy Solar International Inc. State Licensed Solar Contractor License # CVC56695 wa...@pureenergysolar.com http://pureenergysolar.com 352 377-6527 Office 352 336-3299 Fax 352 316-1637 Cell The content of this message is Pure Energy Solar Confidential. If you are not the intended recipient and have received this message in error, any use or distribution is prohibited. Please notify me immediately by reply e-mail and delete this message from your computer system. Thank you. From: bo...@electronconnection.com Date: Tue, 31 May 2011 16:59:43 -0700 To: re-wrenches@lists.re-wrenches.org Subject: Re: [RE-wrenches] 24 volt Battery Bank comparison Wayne,I'd recommend against that. To do an effective equalization charge on that bank you'll need to get the voltage up to at least 2.6-2.7V per cell. That would mean a 13 cell pack voltage of 34-35V. Got any DC loads at all? Danger, Will Robinson, Danger! Using the inverter as a charging source? I think you'll run out of transformer windings or at the very least reduce your amperage output greatly toward the end of that cycle.Hopefully, Jamie can jump in with an opinion here as well.Good Luck!Bob-O On May 31, 2011, at 4:28 PM, Wayne Irwin wrote:Just for a little extra. Wayne Irwin, EE Director of Engineering Pure Energy Solar International Inc. State Licensed Solar Contractor License # CVC56695 wa...@pureenergysolar.com http://pureenergysolar.com 352 377-6527 Office 352 336-3299 Fax 352 316-1637 Cell The content of this message is Pure Energy Solar Confidential. If you are not the intended recipient and have received this message in error, any use or distribution is prohibited. Please notify me immediately by reply e-mail and delete this message from your computer system. Thank you. ___ 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 volt Battery Bank comparison
Hi Wayne,
Why not 12 cells (24VDC) and put the 13th in storage as DRY?
Regards,
Jamie
Wayne Irwin wa...@pureenergysolar.com 5/31/2011 9:01 PM
A) With a 13th battery and only one string, if there were a failure in
one of the cells, the system would most likely demonstrate the failure
rather quickly and allow for the faulty battery to be removed while
still maintaining adequate voltage to operate the 24V system.
B) On the other hand, Tom presents the exact reason behind the idea of
the 3 - string design.
This is an off grid system.
I know this may open up a can of (philosophically varied) worms. But,
this is the reasoning behind the two designs.
PS. Buss bars (if 3 strings) and 4/0 CU would be used.
Wayne Irwin, EE
Director of Engineering
Pure Energy Solar International Inc.
State Licensed Solar Contractor
License # CVC56695
wa...@pureenergysolar.com ( mailto:pureenergyso...@hotmail.com )
http://pureenergysolar.com ( http://pureenergysolar.net/ )
352 377-6527 Office
352 336-3299 Fax
352 316-1637 Cell
The content of this message is Pure Energy Solar Confidential. If you
are not the intended recipient and have received this message in error,
any use or distribution is prohibited. Please notify me immediately by
reply e-mail and delete this message from your computer system. Thank
you.
From: t...@wagonmaker.com
To: re-wrenches@lists.re-wrenches.org
Date: Tue, 31 May 2011 13:36:16 -1000
Subject: Re: [RE-wrenches] 24 volt Battery Bank comparison
.ExternalClass .ecxhmmessage P {padding:0px;} .ExternalClass
body.ecxhmmessage {font-size:10pt;font-family:Tahoma;}
From a reliability standpoint I would never want to bet the farm on one
string. All it takes is the failure of one cell and the system is
useless until it is replaced. Three strings means a cell failure only
reduces capacity by 33% not 100%. I’ve always thought in off-grid
systems it is a good idea to build in as much redundancy as possible
whenever possible. Oh, and always use a buss bar system with multiple
strings, it makes for a far more stable system with less stress on the
batteries.
Tom
From: Wayne Irwin ( mailto:wa...@pureenergysolar.com )
Sent: Tuesday, May 31, 2011 11:49 AM
To: Wrenches ( mailto:re-wrenches@lists.re-wrenches.org )
Subject: [RE-wrenches] 24 volt Battery Bank comparison
Hello Esteemed Battery Gurus,
Which of the following do you believe is the better 24 V battery bank?
A) 13 - Rolls 2-YS-31 2430 AH @ 20 HR (one string)
or
B) 9 - Rolls 8-CS-25P 820 AH @ 20 HR (3 strings of 3)
Thank you in advance for your input!
Wayne Irwin, EE
Director of Engineering
Pure Energy Solar International Inc.
State Licensed Solar Contractor
License # CVC56695
mailto:pureenergyso...@hotmail.com
http://pureenergysolar.com ( http://pureenergysolar.net/ )
352 377-6527 Office
352 336-3299 Fax
352 316-1637 Cell
The content of this message is Pure Energy Solar Confidential. If you
are not the intended recipient and have received this message in error,
any use or distribution is prohibited. Please notify me immediately by
reply e-mail and delete this message from your computer system. Thank
you.
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Re: [RE-wrenches] 24 volt Battery Bank comparison
Tom,
Yes, but if you use individual 2V cells, you can pull one failed
cell out of the string and get by just fine by adjusting setpoints
down by 8% (11/12ths). You'll lose 8% of capacity until a cell is
replaced; or, if the failed cell is the first to go at end-of-life,
just live with the remaining 22V bank while collecting funds for the
replacement set ("You have been setting aside some money each year
for that set, haven't you?").
Using two strings is fine, but if the smaller strings are made up of
4V or 6V cases, you no longer can remove just one cell. Rather, you
must disconnect one string and live on 50% capacity (or 67% with two
out of three strings) until a replacement is secured.
Based on the above, I'd usually go with a single string of the best
batteries I can find. Personally, I like what Chris Worcester wrote:
My one string of 1476 AH IBE 2 V cells went 19 years
before retiring them to a neighbor’s off grid system, where they
are now working. One string has my vote!
as
I just put that exact size of IBE 2V cells in my own home. Here's hoping I get
another 18 years and 10 months out of them.
Allan
Allan Sindelar
al...@positiveenergysolar.com
NABCEP Certified Photovoltaic
Installer
NABCEP Certified Technical Sales Professional
New Mexico EE98J Journeyman Electrician
Positive Energy, Inc.
3201 Calle Marie
Santa Fe, New Mexico 87507
505 424-1112
www.positiveenergysolar.com
On 5/31/2011 5:36 PM, Tom Elliot wrote:
From a reliability standpoint I would never want to bet
the farm on one string. All it takes is the failure of one
cell and the system is useless until it is replaced. Three
strings means a cell failure only reduces capacity by 33%
not 100%. I’ve always thought in off-grid systems it is a
good idea to build in as much redundancy as possible
whenever possible. Oh, and always use a buss bar system
with multiple strings, it makes for a far more stable system
with less stress on the batteries.
Tom
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Re: [RE-wrenches] 24 volt Battery Bank comparison
Just another thought- If redundancy is an issue with string sizing, having a 12v inverter handy is sometimes a viable backup option with a 24v bank with 2 or more parallel strings. Jason Szumlanski Fafco Solar On May 31, 2011, at 7:55 PM, Jason Szumlanski ja...@fafcosolar.com wrote: If the choice is one or three, I choose one. If the choice is one or two, I choose two for the same redundancy benefit echoed by others. However, it sometimes depends how remote the system is. If you are a few miles down the road from a stocking battery distributor, one string is great. If you are a boat ride or a 10 hour 4x4 crawl at 2 mph away, redundancy may be critical. It all depends on the situation. I would even consider three strings if the location has serious access problems and the customer can only survive with 33% capacity loss for a period of time. While I have my favorite brands, sometimes you have to go with a brand that fits the right capacity and string arrangement. Fortunately Rolls has lots of options, so you should find a suitable alternative. I start with my desired V, aH, and parallel strings, then let the manufacturer or distributor do the work and recommend options. Not that I don't do my research, but sometimes they come up with a better option than you initially think of. Jason Szumlanski Fafco Solar On May 31, 2011, at 6:25 PM, Brian Mehalic br...@solarenergy.org wrote: Hi Wayne- While I think a lot of folks will agree that a single string is better for the long term health of the batteries as it results in more even charging, I still like the idea of at least two strings. That way if a single battery fails, that string can be removed and the end-user can at least get by on half of the pack until a replacement can be installed. Brian On Tue, May 31, 2011 at 10:19 PM, James Surrette ja...@surrette.com wrote: Hi Wayne, I look forward to the input from the wrenches. My recommendation, regardless of the brand, would be for one string. Regards, Jamie Wayne Irwin wa...@pureenergysolar.com 5/31/2011 6:49 PM Hello Esteemed Battery Gurus, Which of the following do you believe is the better 24 V battery bank? A) 13 - Rolls 2-YS-31 2430 AH @ 20 HR (one string) or B) 9 - Rolls 8-CS-25P 820 AH @ 20 HR (3 strings of 3) Thank you in advance for your input! Wayne Irwin, EE Director of Engineering Pure Energy Solar International Inc. State Licensed Solar Contractor License # CVC56695 wa...@pureenergysolar.com http://pureenergysolar.com 352 377-6527 Office 352 336-3299 Fax 352 316-1637 Cell The content of this message is Pure Energy Solar Confidential. If you are not the intended recipient and have received this message in error, any use or distribution is prohibited. Please notify me immediately by reply e-mail and delete this message from your computer system. Thank you. This email and its attachments have been scanned by iConnection E-Mail Firewall for viruses, spam, and malicious content. The information transmitted in this email is intended only for the entity or person to which it is addressed and may contain confidential/privileged material. If you received this in error, please contact the sender and delete the material from any computer. Any review, retransmission, dissemination, or other use of this information by persons or entities other than the intended recipient is strictly prohibited. %^^% ___ 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 -- Brian Mehalic NABCEP Certified Solar PV Installer™ R031508-59 IREC ISPQ Certified Affiliated Instructor/PV US-0132 PV Curriculum Developer and Instructor Solar Energy International Carbondale, CO 81623 http://www.solarenergy.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 ___ 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:
Re: [RE-wrenches] 24 volt Battery Bank comparison
I think the verdict is 12 - Rolls 2-YS-31 2430 AH @ 20 HR (one string) and one dry spare in storage is the best case scenario! Wayne Irwin, EE Director of Engineering Pure Energy Solar International Inc. State Licensed Solar Contractor License # CVC56695 wa...@pureenergysolar.com http://pureenergysolar.com 352 377-6527 Office 352 336-3299 Fax 352 316-1637 Cell The content of this message is Pure Energy Solar Confidential. If you are not the intended recipient and have received this message in error, any use or distribution is prohibited. Please notify me immediately by reply e-mail and delete this message from your computer system. Thank you. Date: Tue, 31 May 2011 18:16:56 -0600 From: al...@positiveenergysolar.com To: re-wrenches@lists.re-wrenches.org Subject: Re: [RE-wrenches] 24 volt Battery Bank comparison Tom, Yes, but if you use individual 2V cells, you can pull one failed cell out of the string and get by just fine by adjusting setpoints down by 8% (11/12ths). You'll lose 8% of capacity until a cell is replaced; or, if the failed cell is the first to go at end-of-life, just live with the remaining 22V bank while collecting funds for the replacement set (You have been setting aside some money each year for that set, haven't you?). Using two strings is fine, but if the smaller strings are made up of 4V or 6V cases, you no longer can remove just one cell. Rather, you must disconnect one string and live on 50% capacity (or 67% with two out of three strings) until a replacement is secured. Based on the above, I'd usually go with a single string of the best batteries I can find. Personally, I like what Chris Worcester wrote: My one string of 1476 AH IBE 2 V cells went 19 years before retiring them to a neighbor’s off grid system, where they are now working. One string has my vote! as I just put that exact size of IBE 2V cells in my own home. Here's hoping I get another 18 years and 10 months out of them. Allan Message body Allan Sindelar al...@positiveenergysolar.com NABCEP Certified Photovoltaic Installer NABCEP Certified Technical Sales Professional New Mexico EE98J Journeyman Electrician Positive Energy, Inc. 3201 Calle Marie Santa Fe, New Mexico 87507 505 424-1112 www.positiveenergysolar.com On 5/31/2011 5:36 PM, Tom Elliot wrote: From a reliability standpoint I would never want to bet the farm on one string. All it takes is the failure of one cell and the system is useless until it is replaced. Three strings means a cell failure only reduces capacity by 33% not 100%. I’ve always thought in off-grid systems it is a good idea to build in as much redundancy as possible whenever possible. Oh, and always use a buss bar system with multiple strings, it makes for a far more stable system with less stress on the batteries. Tom ___ 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 volt Battery Bank comparison
I'd vote to listen to the manufacturer. It's in their best interest to provide a reliable solution. Good call. On May 31, 2011, at 8:23 PM, Wayne Irwin wa...@pureenergysolar.com wrote: I think the verdict is 12 - Rolls 2-YS-31 2430 AH @ 20 HR (one string) and one dry spare in storage is the best case scenario! Wayne Irwin, EE Director of Engineering Pure Energy Solar International Inc. State Licensed Solar Contractor License # CVC56695 wa...@pureenergysolar.com http://pureenergysolar.com 352 377-6527 Office 352 336-3299 Fax 352 316-1637 Cell The content of this message is Pure Energy Solar Confidential. If you are not the intended recipient and have received this message in error, any use or distribution is prohibited. Please notify me immediately by reply e-mail and delete this message from your computer system. Thank you. Date: Tue, 31 May 2011 18:16:56 -0600 From: al...@positiveenergysolar.com To: re-wrenches@lists.re-wrenches.org Subject: Re: [RE-wrenches] 24 volt Battery Bank comparison Tom, Yes, but if you use individual 2V cells, you can pull one failed cell out of the string and get by just fine by adjusting setpoints down by 8% (11/12ths). You'll lose 8% of capacity until a cell is replaced; or, if the failed cell is the first to go at end-of-life, just live with the remaining 22V bank while collecting funds for the replacement set (You have been setting aside some money each year for that set, haven't you?). Using two strings is fine, but if the smaller strings are made up of 4V or 6V cases, you no longer can remove just one cell. Rather, you must disconnect one string and live on 50% capacity (or 67% with two out of three strings) until a replacement is secured. Based on the above, I'd usually go with a single string of the best batteries I can find. Personally, I like what Chris Worcester wrote: My one string of 1476 AH IBE 2 V cells went 19 years before retiring them to a neighbor’s off grid system, where they are now working. One string has my vote! as I just put that exact size of IBE 2V cells in my own home. Here's hoping I get another 18 years and 10 months out of them. Allan Allan Sindelar al...@positiveenergysolar.com NABCEP Certified Photovoltaic Installer NABCEP Certified Technical Sales Professional New Mexico EE98J Journeyman Electrician Positive Energy, Inc. 3201 Calle Marie Santa Fe, New Mexico 87507 505 424-1112 www.positiveenergysolar.com On 5/31/2011 5:36 PM, Tom Elliot wrote: From a reliability standpoint I would never want to bet the farm on one string. All it takes is the failure of one cell and the system is useless until it is replaced. Three strings means a cell failure only reduces capacity by 33% not 100%. I’ve always thought in off-grid systems it is a good idea to build in as much redundancy as possible whenever possible. Oh, and always use a buss bar system with multiple strings, it makes for a far more stable system with less stress on the batteries. Tom ___ 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 ___ 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 volt Battery Bank comparison
Good on the buss bars Wayne. Using them removes the concerns about multiple strings and increases redundancy and system stability. You won’t need 4/0 between single strings and the buss bar, you can probably easily use smaller cable, just size it for the individual string. 4/0 to the inverter of course. I echo the concern about the higher voltage bank though. Most off-grid systems have some low voltage DC elements, or at least offer the opportunity to add them, so the higher voltage could be a problem, especially during equalization. If you use the buss bars, keep system voltage high enough, and the batteries are well-cared for, it shouldn’t be necessary to add that one extra battery. From: Wayne Irwin Sent: Tuesday, May 31, 2011 2:05 PM To: Wrenches Subject: Re: [RE-wrenches] 24 volt Battery Bank comparison No DC loads at all. Wayne Irwin, EE Director of Engineering Pure Energy Solar International Inc. State Licensed Solar Contractor License # CVC56695 mailto:pureenergyso...@hotmail.com http://pureenergysolar.com 352 377-6527 Office 352 336-3299 Fax 352 316-1637 Cell The content of this message is Pure Energy Solar Confidential. If you are not the intended recipient and have received this message in error, any use or distribution is prohibited. Please notify me immediately by reply e-mail and delete this message from your computer system. Thank you. From: bo...@electronconnection.com Date: Tue, 31 May 2011 16:59:43 -0700 To: re-wrenches@lists.re-wrenches.org Subject: Re: [RE-wrenches] 24 volt Battery Bank comparison Wayne, I'd recommend against that. To do an effective equalization charge on that bank you'll need to get the voltage up to at least 2.6-2.7V per cell. That would mean a 13 cell pack voltage of 34-35V. Got any DC loads at all? Danger, Will Robinson, Danger! Using the inverter as a charging source? I think you'll run out of transformer windings or at the very least reduce your amperage output greatly toward the end of that cycle. Hopefully, Jamie can jump in with an opinion here as well. Good Luck! Bob-O On May 31, 2011, at 4:28 PM, Wayne Irwin wrote: Just for a little extra. Wayne Irwin, EE Director of Engineering Pure Energy Solar International Inc. State Licensed Solar Contractor License # CVC56695 mailto:pureenergyso...@hotmail.com http://pureenergysolar.com 352 377-6527 Office 352 336-3299 Fax 352 316-1637 Cell The content of this message is Pure Energy Solar Confidential. If you are not the intended recipient and have received this message in error, any use or distribution is prohibited. Please notify me immediately by reply e-mail and delete this message from your computer system. Thank you. ___ 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 No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1375 / Virus Database: 1509/3671 - Release Date: 05/31/11 ___ 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 volt Battery Bank comparison
On 2011-05-31 20:14, Tom Elliot wrote: Good on the buss bars Wayne. Using them removes the concerns about multiple strings and increases redundancy and system stability. You won’t need 4/0 between single strings and the buss bar, you can probably easily use smaller cable, just size it for the individual string. 4/0 to Part of the argument for having multiple strings is for redundancy. If smaller interconnect cables are used, they will likely not have the required ampacity and OCPD to support the full load. In the event of part of the bank needing to be pulled offline there will be downtime and expense associated with upgrading the smaller interconnect cables to support the full load or the proportionally increased load. Food for thought, -James Jarvis ___ 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 volt Battery Bank comparison
Wayne, Whenever possible, always design a battery bank for a single series string. Parallel strings require more attention and increase the probability of early failure due to unequal charging. Larry Crutcher Starlight Solar Power Systems 11871 S Fortuna Road, #210 Yuma, AZ 85367 la...@starlightsolar.com (928) 342-9103 On May 31, 2011, at 2:49 PM, Wayne Irwin wrote: Hello Esteemed Battery Gurus, Which of the following do you believe is the better 24 V battery bank? A) 13 - Rolls 2-YS-31 2430 AH @ 20 HR (one string) or B) 9 - Rolls 8-CS-25P 820 AH @ 20 HR (3 strings of 3) Thank you in advance for your input! Wayne Irwin, EE Director of Engineering Pure Energy Solar International Inc. State Licensed Solar Contractor License # CVC56695 wa...@pureenergysolar.com http://pureenergysolar.com 352 377-6527 Office 352 336-3299 Fax 352 316-1637 Cell The content of this message is Pure Energy Solar Confidential. If you are not the intended recipient and have received this message in error, any use or distribution is prohibited. Please notify me immediately by reply e-mail and delete this message from your computer system. Thank you. ___ 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 volt Battery Bank comparison
Oops! Guess I should have read all the posts before I reply;- Larry Crutcher On May 31, 2011, at 5:23 PM, Wayne Irwin wrote: I think the verdict is 12 - Rolls 2-YS-31 2430 AH @ 20 HR (one string) and one dry spare in storage is the best case scenario! Wayne Irwin, EE Director of Engineering Pure Energy Solar International Inc. State Licensed Solar Contractor License # CVC56695 wa...@pureenergysolar.com http://pureenergysolar.com 352 377-6527 Office 352 336-3299 Fax 352 316-1637 Cell The content of this message is Pure Energy Solar Confidential. If you are not the intended recipient and have received this message in error, any use or distribution is prohibited. Please notify me immediately by reply e-mail and delete this message from your computer system. Thank you. Date: Tue, 31 May 2011 18:16:56 -0600 From: al...@positiveenergysolar.com To: re-wrenches@lists.re-wrenches.org Subject: Re: [RE-wrenches] 24 volt Battery Bank comparison Tom, Yes, but if you use individual 2V cells, you can pull one failed cell out of the string and get by just fine by adjusting setpoints down by 8% (11/12ths). You'll lose 8% of capacity until a cell is replaced; or, if the failed cell is the first to go at end-of-life, just live with the remaining 22V bank while collecting funds for the replacement set (You have been setting aside some money each year for that set, haven't you?). Using two strings is fine, but if the smaller strings are made up of 4V or 6V cases, you no longer can remove just one cell. Rather, you must disconnect one string and live on 50% capacity (or 67% with two out of three strings) until a replacement is secured. Based on the above, I'd usually go with a single string of the best batteries I can find. Personally, I like what Chris Worcester wrote: My one string of 1476 AH IBE 2 V cells went 19 years before retiring them to a neighbor’s off grid system, where they are now working. One string has my vote! as I just put that exact size of IBE 2V cells in my own home. Here's hoping I get another 18 years and 10 months out of them. Allan Allan Sindelar al...@positiveenergysolar.com NABCEP Certified Photovoltaic Installer NABCEP Certified Technical Sales Professional New Mexico EE98J Journeyman Electrician Positive Energy, Inc. 3201 Calle Marie Santa Fe, New Mexico 87507 505 424-1112 www.positiveenergysolar.com On 5/31/2011 5:36 PM, Tom Elliot wrote: From a reliability standpoint I would never want to bet the farm on one string. All it takes is the failure of one cell and the system is useless until it is replaced. Three strings means a cell failure only reduces capacity by 33% not 100%. I’ve always thought in off-grid systems it is a good idea to build in as much redundancy as possible whenever possible. Oh, and always use a buss bar system with multiple strings, it makes for a far more stable system with less stress on the batteries. Tom ___ List sponsored by Home Power magazine List Address: re-wrenc...@lists.re-wrenches.orgOptions 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 ___ 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
