Good info, I thought maybe the warm days the system might drag the voltage to low, that's why I asked.
So, on to MPPT controllers. Again limited use, so looking for some good info. Kinda limited battery experience to be honest. Just very small cabin/shacks. Rewiring an array in this scenario would increase voltage to the controller, and the controller then sacrifice (for lack of a better word) voltage and increase the current? Just looking at the ISC numbers of the array now it produces 69.2 at STC, would the re-wired array produce similar current but match programmed setpoints? Jesse Sent from my iPhone On May 13, 2013, at 9:51 PM, Kirpal Khalsa <solarwo...@gmail.com> wrote: > Jesse.....why wouldn't you wire at least 2 modules in series....this way you > have less breakers to deal with, less cord grips if paralleling in a combiner > box, less homerun cables to the combiner and you will also benefit from > greater energy harvest in your MPPT conversion particularly during cold > weather.... > If you go with 1 module strings and have hot weather your voltage sag in the > summer you will be on the low edge of voltage window to properly charge a 24V > battery bank..... > i would check the charge voltage recommendations from the battery > manufacturer for proper charging parameters....usually the voltage > recommendations call for lower voltages than FLA batteries...may be helpful > for being able to charge your sealed batteries from a single module. It is > still borderline... > I have always believed that the 60 cell modules were a bit on the low side > for 24V battery charging. In the past that is what the 72 cell modules were > for....but those are fewer and farther between these days, except int he > larger 300+ watt modules.... > If you had 9 modules i would even go with strings of 3....or if you want to > get really efficient you could wire in strings of 4 with the Midnite Solar > Classic 200 charge controller.....you would definitely be bumping into > amperage limits.....but that is ok... > good luck... > > > Sunny Regards, > Kirpal Khalsa > NABCEP Certified PV Installation Professional > Renewable Energy Systems > www.oregonsolarworks.com > 541-218-0201 m > 541-592-3958 o > > > On Mon, May 13, 2013 at 7:34 PM, Jesse Dahl <dahlso...@gmail.com> wrote: >> Hello, >> >> I'm interested in charging voltages for AGM batteries. After my visit to the >> site mentioned in the battery box thread, I was thinking about the system. >> >> New install, 8 solarworld 255s charging a 24V battery bank through a outback >> FM80 (MPPT) All 8 modules in parallel. >> VOC - 37.8 >> VMP - 31.4 >> ISC - 8.66 >> IMP - 8.15 >> >> I'm interested in the setpoints people use for AGMs because it seems like >> this might be cutting it close to the setpoints based on the array voltage. >> Since the system is using a MPPT controller would it be better to increase >> the array voltage? >> >> Battery bank is 6 12V 245ah east penn bats wired 3 strings of 2. >> >> I haven't used sealed batteries outside my fish house and boat so I'm >> looking for some detailed info if I can get it. >> >> Thanks a lot! >> >> Jesse >> >> >> Sent from my iPhone >> _______________________________________________ >> List sponsored by Home Power magazine >> >> List Address: RE-wrenches@lists.re-wrenches.org >> >> Change email address & settings: >> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org >> >> List-Archive: >> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org >> >> List rules & etiquette: >> www.re-wrenches.org/etiquette.htm >> >> Check out participant bios: >> www.members.re-wrenches.org > > _______________________________________________ > List sponsored by Home Power magazine > > List Address: RE-wrenches@lists.re-wrenches.org > > Change email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out participant bios: > www.members.re-wrenches.org >
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