Hello Wrenches:
I have always insulated my battery boxes (or the battery room). I have
built hundreds of battery boxes, and insulated them all with 1-1/2" rigid foam.
I have never seen the foam deteriorate, with 15+ years experience on many
sites. As you know, the capacity of the batteries is much lower when the
batteries get cold, so adding insulation will certainly improve the performance
of the battery.
Unfortunately, I have seen thermal runaway occur on one battery bank in
2002, but that was due to other circumstances. However, the insulation probably
didn't help the batteries cool, in that one instance. When I got to the site,
the generator had been running for 3 very hot days, continuously pumping
current
into DRY batteries that should have been flooded. The batteries had begun to
melt, and some had become blobs of maroon plastic. Those L-16s were only five
years old at the time.
Nick Soleil
Project Manager
Advanced Alternative Energy Solutions, LLC
PO Box 657
Petaluma, CA 94953
Cell: 707-321-2937
Office: 707-789-9537
Fax: 707-769-9037
________________________________
From: Allan Sindelar <[email protected]>
To: [email protected]
Sent: Fri, December 10, 2010 8:36:00 AM
Subject: Re: [RE-wrenches] To insulate a battery bank
Bob,
Extruded polystyrene ("blueboard" or "pinkboard", depending on brand) is
designed for direct-burial use, and is unaffected by direct and continuous
contact with battery acid. It's also strong enough to directly support the
weight of the batteries. So it's a useful material to use, if you have need
of insulation.
I'll use it if an otherwise tempered space for the batteries has a cold
slab
or dirt floor, in order to inhibit long-term conductive heat loss.
Otherwise, I agree with the others here about the lack of benefit of
insulation in battery enclosures. Fundamentally, insulation just retards
the
rate of heat transfer from a warmer space to a cooler one. Batteries don't
generate significant heat at times when the heat is most needed, so they
will eventually maintain the same average temperature as their immediate
environment.
If batteries are directly exposed to sunlight through a window, insulation
is called for, to prevent the cells directly exposed to the sun's heat from
warming more than the shaded cells.
When asked, I recommend either putting batteries indoors (with proper
sealed
enclosure with controlled ventilation to the outdoors) or in a separate
insulated, sun-tempered space, such as a power shed, with passive solar
glazing and mass storage, but with no auxiliary heat. Of course, what works
here in the sunny Southwest wouldn't work as well in your region.
Allan
AllanSindelar
[email protected]
NABCEP Certified Photovoltaic Installer
EE98J Journeyman Electrician
Positive Energy, Inc.
3201 Calle Marie
Santa Fe, New Mexico 87507
505 424-1112
www.positiveenergysolar.com
On 12/10/2010 4:32 AM, bob ellison wrote:
>With the amount of lead in a battery bank it changes temperature
>very slowly. Both gaining and losing heat is a very slow process.
>I have never insulated battery banks, if in a cold area like
>here
>we size them larger for the slower reaction time in the
>
>winter anyway. Part of the reason being that I would bet that
>the
>acid would raise hell with the insulation!
>
>We regularly see battery banks that are 40 degrees or so it
>presents no problem.
>If the exhaust fan is running in a 70 degree building all it
>does
>is draw the warm air over the top of the battery and not really
>warm them much anyway, in an unheated building it will probably
>
>not make much difference.
>The only way that I would put insulation in an unheated battery
>box is on the outside of the plywood, away from the acid and
>gasses. I would also make it removable in the summer.
>
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