Frostbite [RE-wrenches]

[Jeff Clearwater]

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Hi Jeff,

We used the electric warming pads for batteries sold in auto supply 
stores here in the lower 48 for our electric vehicle battery boxes 
with mixed success.  They fail.  Now that may be due to vibration and 
jossling around in an Civic or S10 but I have not been very impressed 
with them - The electrical connections are cheap and get corroded 
with battery acid easily - the kind we used was orange - rubbery 
(neoprene?) and - about 4" x 6" - with just a lamp type cord emerging 
from the corner. About $15 each.  May work better in a stationary 
application.  As I remember they drew about 60 watts each (so we 
wired two in series to bring that down to about 30 Watts each).

2 KWH/day is about 83 watts continuous or about 283 BTUs/Hr.  You 
might want to run some temperature rise calcs on what that will do to 
x lbs of lead and x lbs of acid water at your temps.  It was pretty 
easy to overheat the batteries in an enclosed battery box - I 
remember we actually melted the styrene on our first attempts which 
is why we dropped them down to 30 watts each.

Sure would rather see you use earth heat like you suggest!

Hope that helps!

Jeff C.
Village Power Design

>Anyone have some cleaver and RELIABLE tricks for keeping batteries 
>from freezing up in AK where I can see -40F for long winter periods? 
>In the past I've placed them in 9' deep root cellars with great luck 
>(stays at 32F) but this client is not interested in that approach.
>At this point I'm considering electric soil warming mats under the 
>batteries in a well insulated box. I can probably spare 2 or so 
>kWh/day. No one will be there for at least 3 months.
>Thanks!
>-jeff o
>
>
>>From the Solar, Wind and Hydro powered office of Jeff Oldham
>
>
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-- 
~~~~~~~~~~~~~
Jeff Clearwater
Village Power Design Associates
Sustainable Energy & Water Solutions for Home & Village
http://www.villagepower.com
gosolar at villagepower.com

530-470-9166
877-SOLARVillage
877-765-2784
425 Nimrod St.
Nevada City, CA 95959
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~`~

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