<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:arial,helvetica,sans-serif;font-size:12pt">Hello Wrenches:<br> 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.<br> 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.<br>Nick Soleil<br>Project Manager<br>Advanced Alternative Energy Solutions, LLC<br>PO Box 657<br>Petaluma, CA 94953<br>Cell: 707-321-2937<br>Office: 707-789-9537<br>Fax: 707-769-9037<div><br></div><div style="font-family: arial,helvetica,sans-serif; font-size: 12pt;"><br><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"><font face="Tahoma" size="2"><hr size="1"><b><span style="font-weight: bold;">From:</span></b> Allan Sindelar <allan@positiveenergysolar.com><br><b><span style="font-weight: bold;">To:</span></b> re-wrenches@lists.re-wrenches.org<br><b><span style="font-weight: bold;">Sent:</span></b> Fri, December 10, 2010 8:36:00 AM<br><b><span style="font-weight: bold;">Subject:</span></b> Re: [RE-wrenches] To insulate a battery bank<br></font><br>
Bob,<br>
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.<br>
<br>
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. <br>
<br>
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. <br>
<br>
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.<br>
Allan<br>
<br>
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<p class="MsoNormal" style=""><span class="il"><b style="">Allan</b></span><b style=""> Sindelar</b><span style="font-size: 10pt;"><br>
<a rel="nofollow" ymailto="mailto:Allan@positiveenergysolar.com" target="_blank" href="mailto:Allan@positiveenergysolar.com"><span class="il">Allan</span>@positiveenergysolar.com</a><br>
NABCEP Certified Photovoltaic Installer<br>
EE98J Journeyman Electrician<br>
<b style="">Positive Energy, Inc.</b><br>
3201 Calle Marie<br>
Santa Fe, New Mexico 87507<br>
<b style="">505 424-1112</b><br>
<a rel="nofollow" target="_blank" href="http://www.positiveenergysolar.com/">www.positiveenergysolar.com</a></span></p>
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On 12/10/2010 4:32 AM, bob ellison wrote:
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<p class="MsoNormal"><font color="black" face="Calibri" size="4"><span style="font-size: 14pt; color: black;">With the amount of
lead in a battery bank it changes temperature very slowly.
Both gaining and losing heat is a very slow process.</span></font></p>
<p class="MsoNormal"><font color="black" face="Calibri" size="4"><span style="font-size: 14pt; color: black;">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! </span></font></p>
<p class="MsoNormal"><font color="black" face="Calibri" size="4"><span style="font-size: 14pt; color: black;">We regularly see
battery banks that are 40 degrees or so it presents no
problem.</span></font></p>
<p class="MsoNormal"><font color="black" face="Calibri" size="4"><span style="font-size: 14pt; color: black;">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.</span></font></p>
<p class="MsoNormal"><font color="black" face="Calibri" size="4"><span style="font-size: 14pt; color: black;">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.</span></font></p>
<p class="MsoNormal"><font face="Calibri" size="4"><span style="font-size: 14pt;"> </span></font></p>
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