Re: [RE-wrenches] Air conditioning for batteries in highPartially right, Jim.
Except hotter internal temperatures cause the electro-chemical process to be
faster, not slower. Only as temperatures decrease below 25C, which may vary
with manufacturer, is the process slowed.
Larry
----- Original Message -----
From: North Texas Renewable Energy Inc
To: RE-wrenches
Sent: Friday, April 22, 2011 12:54 PM
Subject: Re: [RE-wrenches] Air conditioning for batteries in hightemperature
climate
It's the efficiency of the chemical reaction that creates the loss. The
electrolyte solution cannot pull out nor put back the same amount of 'energy'
in hotter or colder conditions. When temperatures moderate, the chemical
reaction returns to its nominal efficiency. The batterys capacity should not be
permanently affected unless SOC reaches extreme levels.
Or that's how I recall the process explained for cold temps. I assume the
same is true for high temps.
Jim
-----Original Message-----
From: [email protected]
[mailto:[email protected]]On Behalf Of Hugh
Sent: Friday, April 22, 2011 2:13 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Air conditioning for batteries in high
temperature climate
Hi Roy,
Hi temperatures will hit the battery capacity but will the battery
efficiency be that much affected? If the battery capacity is inadequate then
you need to compare the aircon running cost to the cost of buying a 10% larger
battery. Don't you?
Cheers
Hugh
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: [email protected]
[mailto:[email protected]] 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
[email protected]
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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