Re: [RE-wrenches] Air conditioning for batteries in high temperature climate

[Roy Butler]

Bob is correct, I do have an off grid client that uses an AC unit to keep the batteries cool. Although we're not in a high temp climate, it does get into the 80's and low 90's here in the summer. By my calculations, he was losing an 'average' of 10% storage capacity during the 5 month period from late spring to early fall. In July and August it was closer to 18%, but for calculation purposes, 10% is close enough. His bank capacity is 4800AH @ 48 VDC. That's 230,400 watt hours and 10% of that rounds out to 23,000 watt hours lost to heat. I showed up one day to check something in the power shed and was dismayed to see a window AC unit installed there. An interesting customer discussion ensued and I had to admit he was correct in his calculations. The Energy Star rated AC unit consumes no more than 3,000 watt hours per day, even in the highest heat. Essentially, he's 'spending" 3 kilowatt hours to 'buy back' 20 kilowatt hours of storage. He got me on that one! That reasoning didn't work on the 6 other AC units that appeared on his house the following week. But that's another story altogether! Roy Butler NABCEP Certified Solar PV Installer® NYSERDA eligible PV & wind installer PA Sunshine Program Approved PV Installer Four Winds Renewable Energy, LLC 8902 Route 46 Arkport, NY 14807 607-324-9747 www.four-winds-energy.com Although no trees were killed in the sending of this message, a large number of electrons were terribly inconvenienced. On 4/22/2011 7:40 AM, bob ellison wrote: I believe Roy has a customer with a huge battery bank that air conditioned the battery room. He ran the numbers and the air conditioning actually made sense.   Bob Ellison   From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of R Ray Walters Sent: Thursday, April 21, 2011 4:50 PM To: RE-wrenches Subject: Re: [RE-wrenches] Air conditioning for batteies in high temperature climate   Are you using temperature compensation? It lowers the voltage when its hot. Also, have you considered setting the batteries in a below ground vault? I've had good luck with in floor battery boxes. Finally, AGMs and L16s just don't last very long anyway. AGMs maybe 3 years, and L16s I've seen die in under 5 years and we get to 15 below zero. My suggestion: temp comp, ground vault, HUP or equivalent cycle life.   R. Walters r...@solarray.com Solar Engineer       On Apr 21, 2011, at 1:22 PM, Starlight Solar, Larry Crutcher wrote: Hello Battery Wrenches,   Over the years I have had several battery banks in Baja and Sonora Mexico fail in just 36 to 48 months. These have been L16 or 8D AGM or flooded banks, 24 and 48 volt systems. The charging systems are working properly and programmed to manufacturer recommended set points and discharges are rarely over 30% DoD.  Some batteries are only used on weekends, some are discharged daily.  I believe what is affecting the short life is the high temperature they live in for 5 months each year. Temps. can hit 115 F in vented battery rooms. I have been thinking about a small air conditioner and insulated battery box to keep the battery at no more than 80 F. There are some portable units that draw about 600 watts and the run time would be very little with a highly insulated enclosure. There is ample power to do this on the home I am changing batteries in now. Has anyone done this and gained longer battery life?   Best Regards, Larry Crutcher Starlight Solar Power Systems powered by STARLIGHT™ _______________________________________________ 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