[RE-wrenches] Air conditioning for batteies in high temperatureclimate

[R Ray Walters]

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
ray at 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
> ray at 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™
>> 
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