Re: Heated Batteries

[steveb@newkla.kla.com (Steven Buchholz)]

WRT warming batteries & blocks with a chemical reaction heater ...

I bought one of those things for keeping myself warm on motorcycle rides
on cold nights (after freezing coming back to San Jose from Santa Maria, 
CA after midnight).  I got one that is a rather large bag (~4"x6"), but 
I doubt that it would generate sufficient heat to warm up a battery, 
much less an engine block.  They may have bigger units, but keep in mind 
that after one has been used it must be placed in boiling water for 
~1/2 hour to reverse the reaction.  Overall they probably aren't all 
that energy efficient.

I've seen people mention some sort of inductive heaters for heating 
engine blocks ... these would probably be more appropriate.  I don't 
know if they are simply resistive heating elements that conduct heat 
to the block, or if they use an alternating magnetic field to create 
eddy currents and heat.  

For remote applications where electric power may not be available it might 
be possible to fashion some sort of blanket to keep the battery warm (may 
be the only advantage of having the battery under the seat).

Final recommendation ... get one of the chemical warmers to keep *YOU* 
warm in the event that your car won't start because the battery/engine 
are too cold.

Steve Buchholz