Thanks for the input guys. On Mon, Oct 10, 2011 at 2:15 PM, Allan Sindelar < [email protected]> wrote:
> ** > Mac, > Adding to Dan's sage advice: > No inverters have amp-hour meters built directly into them. > > Magnum and Outback have the ability through their respective BOS > peripherals to provide that information to the user, but it's not part of > the inverter. Both are shunt-based, meaning that they base SOC and other > data on actually measuring current flow into and out of the batteries, as > does the TriMetric. > > Schneider XW's peripherals also offer user-friendly SOC, but it's not > shunt-based and is thus a much rougher approximation; in one system of ours > a 2HP well pump was a large enough draw to provide a premature low-battery > warning. > > Apollo's inverter has no SOC indication capacity. Voltage and instantaneous > current are the only parameters that can be accessed on the inverter's > display. Anything else requires a data feed to their software on a computer. > Apollo's charge controller has SOC capacity built in, and relies on a shunt > to provide measurement, but the algorithm is faulty; that is, it doesn't > count up and count down at the same rate (this is independent of charge > efficiency factor, i.e. Peukert's coefficient) and relies on the switch into > float to correct the measurement error. This means, for example, that it > will not match the reading on a TriMetric with equivalent setup programming. > > Years ago we decided as policy that we wouldn't sell a system of any size > without a TriMetric (or, back then, an E-Meter). Our logic was that a tiny > system with a clear and user-friendly way to know what's going on inside the > invisible world of batteries and electrons was better than a larger system > with no way to know what was going on. My record was a $1,200 system, > meaning 1/6th of the entire system cost went for the system monitor. I told > customers that if they ever regretted the $200 for the monitor I'd take it > back. Nobody ever took that offer up. > > Allan > > *Allan Sindelar* > *[email protected]* <[email protected]> > 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 10/10/2011 10:21 AM, Dan Fink wrote: > > Mac; > > I'll give it a shot here. > > 1) Yes. EVERYTHING that might consume or produce energy needs to be > connected thru the shunt off the main negative battery terminal for the > amp-hour meter (watt-hour meter, these days) to work correctly; > 1a) I am just getting familiar with the Outback Mate and Flexnet DC > stuff, as we mostly deal with much smaller systems and just use a trimetric, > BUT if you program the Mate correctly, it appears you can tell it exactly > what that functions of multiple shunts in the system are.....as in, one > shunt is wind power in, one is PV in, one is inverter use, maybe one for DC > loads, and the meter then knows what to tally as gain and what as use. just > not enough experience here with this fancy-pants monitoring networking > stuff. I like the trimeteric. > > 2) Don't know. > > 3) Your first step after installing an amp-hour (w-h) meter is to charge > the battery bank full and into float, so the meter learns an initial "zero" > and starts working correctly (counting down from full). And set the charge > controller(s) and the meter so that working together they will trigger this > meter "zero" setpoint. So if you install one on a system with an old battery > bank it will "learn" that setpoint for the old batteries right away. > 3a) As far as how much these meters can actually "learn" I am > skeptical. But if you see big discrepancies -- large tallys of positive > amp-hours for example, or large negative readings when the batteries show > "full"....you can adjust the Peukert coefficient on the meter to be more > accurate for the aged battery bank. As far as how this affects the > "learning" ability, changes all that, I just don't know. > > So, as far as 3a) be aware of it, and maybe tweak the meter settings if > amp-hour readings are consistantly above or below zero. Many off-grid folks > only dream of positive amp-hour numbers. LOL > > Anyway, that's how I would approach it. > > Dan Fink > Executive Director; > Buckville Energy Consulting > Buckville Publications LLC > NABCEP / IREC / ISPQ accredited Continuing Education Providers > http://www.buckville.com/ > [email protected] > 970.672.4342 (voicemail) > 970.373.1311 (fax) > > > > mac Lewis wrote: > > Hello wrenches, > > I am a "greenie" and am curious to know more about amp hr meters. I've > gone on quite a few service calls on existing systems in the area, and I've > never seen one on any of the systems around here. With that being said, I > know on some of the new inverter/chargers incorporate these in their > devices, Apollo Inverters for example. My questions are: > > 1. Is the sole purpose to measure energy into and out of the batteries? > 2. On modern inverters such as the XW, is the SOC meter on the control > panel based on Amphrs or is it simply a voltmeter? > 3. Does an Amphr meter need to be calibrated to older batteries to account > for the increase in internal losses? If so, how? > > Thanks in advance. I really appreciate tapping into this amazing knowledge > base. > > -- > > > > Mac Lewis > > * > > "Yo solo sé que no sé nada." -Sócrates > > * > > > ------------------------------------------------------------------------ > > _______________________________________________ > List sponsored by Home Power magazine > > List Address: [email protected] > > 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: [email protected] > > 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: [email protected] > > 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 > > > -- Mac Lewis * "Yo solo sé que no sé nada." -Sócrates *
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