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Date: Thu, 29 Oct 2009 09:21:12 -0400
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From: "Robert Pastusek" <rpastusek@htii.com>
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Subject: RE: [LML] Battery cooling 4P
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Ralf B wrote:

Dear subscribers,

I moved my battery location from the trunk in front of the firewall. 

I got a TISO550 with an AC compressor on it. The only empty spot that I
found on the firewall was behind the oil cooler. Based on Jeff's advice
I am using 2 12V batteries and stack them on top of each other. I made
an aluminum box that holds both batteries. The box has cut outs on all
sides for weight reduction and that air can get to the batteries.

Question: the exiting air of the oil cooler will hit the batteries
through the big cut out in my battery box. Is this a problem?

I could make a thin cover out of carbon and shield the battery. 

Is it necessary to run a cooling hose from the baffling to the battery
and cool it?

Thanks for your help


Ralf,
Some information and recommendations, but reluctant to dictate what you
should do.
I'd definitely shield the batteries from oil cooler exhaust. The oil coming
out of my oil cooler (Lancair IV-P with TSIO-550E) goes to 200 degrees on a
hot day climb. I suspect the air exiting this heat exchanger is probably
pretty close to this temperature--but have not measured it. If you're using
wet cell batteries, this is well high enough to evaporate (but not boil) the
liquid at a high rate.

I do have temperature monitors just above each exhaust stack and just
forward of the firewall. I have never seen the temp there above 150 degrees;
normally it's around 120-130. Again, I have not measured the temp in your
specific battery location, but I'd think the above temps are representative;
perhaps a bit high because of their close proximity to the exhaust pipes. In
any case, my two (12v in series) Odyssey 680 batteries have worked without a
problem at all in the "normal" battery location...upper right front of
firewall. They are in a closed box, without any external cooling.

Hope this helps?

BOB