My general rule of thumb on batteries is that 100 cycles @ 80%DOD equals about 1 year in an avg. off grid system. Most of the AGMs I see are rated at about 300 cycles, the L16s maybe 550 to 600 cycles, Trojan T105 is 750 cycles, and the HUP is rated at 2100 cycles at 80% DOD. My experience over the past 20 years seems to hold to this rule, although I've had the L16s only go 4 yrs., and the T105 die at 5 yrs. I've definitely had AGMs last longer than 3 yrs, especially in GT systems though. I would think the batteries' avg temp over the 24 hr period would be lower than 100F down in the ground, but I don't live there. Have you considered a passive cooling system like the Cool Cell from Zomeworks? I would think if you're going to put serious money and electrical energy towards cooling, I might look at a water cooled setup: PEX tubing coiled between the batteries, small DC pump to a radiator and fan. Be more direct and efficient than an AC unit.
Just tossing out BS ideas at this point....... R. Walters r...@solarray.com Solar Engineer On Apr 21, 2011, at 3:19 PM, Starlight Solar, Larry Crutcher wrote: > Hi Ray, > > Absolutely: Battery charging 101 = temperature compensated charging, no > exceptions. > > I too thought of underground storage but the temperature is still above 100 > degrees at 6 feet down. It is really hot in the Baja! > > I disagree about AGM life. I have heard others say this about AGM's but it > has not been our experience. I personally have a 900AH bank that is 6 years > old and shows little signs of aging. I have equalized the batteries twice to > keep the capacity up(each one individually, constant current, unregulated > voltage) We only sell and install battery based systems at our retail store > and about 50% of sales are AGM batteries. We have found that they have > similar life to flooded batteries but with great benefits. > > Yes, some L16's just don't hold up well but I am talking about entire banks > failing all at about the same age. > > Thanks for your reply. > > Larry > ----- Original Message ----- > From: R Ray Walters > To: RE-wrenches > Sent: Thursday, April 21, 2011 1:50 PM > Subject: Re: [RE-wrenches] Air conditioning for batteies in high > temperatureclimate > > 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 >
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