# [EVDL] Best insulation for battery box and heater?



## EVDL List (Jul 27, 2007)

There are various types of pipe insulation - -you want the black, more
flexible, more expensive stuff -- armaflex is one brand name. It is
designed for very hot piping (solar thermal pipe runs that may be up to 300F
or more), as opposed to the cheap grey stiff stuff that will melt around
250F or less.

For rigid foam insulation, the polyisocyanurate (yellow foil covered stuff)
is alot more heat resistant than the white or pink of blue stuff. But...
the foil is not exactly nonconductive...

Z



> Benjamin Nelson <[email protected]>wrote:
> 
> > I am working on insulating my battery box and would like to install
> > battery heat-tape under the batteries.
> ...


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## EVDL List (Jul 27, 2007)

Hello Benjamin,

I did not put any heat tape below my batteries. I wrap the battery pack 
with heat blankets that are made by KAT's that you can get at some auto part 
store.

The foil back foam board is too soft where the batteries will press down too 
much. Instead I use the DOW Corning Blue foam that is rated for 25 lbs per 
sq. inch or 3600 lbs per sq.ft. My house and foundation is resting on this 
type of foam.

I first insulated the entire pickup box with this foam that is 2 inches 
thick on the sides and 1 inch thick on the bottom. It is full glue with 
foam glue that is design for this glue.

Then I cover all the foam surfaces with a marine carpet. The fiberglass 
battery box is then cover with this 2 inch foam on the sides and 1 inch foam 
on the bottom. It is also cover with a marine carpet.

The top of the hinge battery box covers have a layer of building aluminum 
foil with the shinny side down. On top of that is a 1/2 inch thick foam 
back marine carpet.

The battery box is size, so there is about 5/8 inch space between the 
batteries and the wall of the box for inserting the battery heat blankets. 
The maximum temperature these heat blankets will get to is 80 F. which is 
about 80 watts per 12 inch wide by 36 inch length. I use four of these 
blankets.

If you look at the KAT's Heat Blanket site, they now have longer ones for 
larger battery packs.

Roland




----- Original Message ----- 
From: "Benjamin Nelson" <[email protected]>
To: <[email protected]>
Sent: Friday, October 23, 2009 10:20 AM
Subject: [EVDL] Best insulation for battery box and heater?


> I am working on insulating my battery box and would like to install
> battery heat-tape under the batteries.
>
> I did an experiment last night. I cut a piece of standard, 1" thick
> pick foam insulation to the size of my battery box, and routed a
> serpertine pattern into it 1/2" thick, and put some "don't let your
> pipes freeze" heat tape in the track.
>
> I set 4 spare batteries of the same size and type (group 31 lead-acid,
> gels) on top of the foam, and put a packing blanket lightly over the
> top of them, to simulate battery box insulation.
>
> I let the heat-tape run over night.
> This morning, the batteries were a nice temperature, about 20 degrees
> F above ambient. However, the heat tape itself MELTED further down
> into the foam.
>
> Can anyone recommend a different insulating material that is still
> water-resistant and non-conductive for use in an EV?
> Otherwise, how about some sort of "heat spreader design?
>
> Thanks,
>
> -Ben Nelson
> Geo Metro EV home-conversion
> "Electro-Metro"
>
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## EVDL List (Jul 27, 2007)

> Benjamin Nelson wrote:
> > I am working on insulating my battery box and would like to install
> > battery heat-tape under the batteries.
> >
> ...


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