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

Fri Apr 22 12:54:39 PDT 2011

Re: [RE-wrenches] Air conditioning for batteries in highIt'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: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org]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: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at 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

      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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--
Hugh Piggott

  Scoraig
  http://www.scoraigwind.co.uk
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