
Uh, Bob, why is the battery warmer than ground temperature?  On the time
scales in question, and with the considerably reduced temperature swings
several feet underground, there isn't going to be any major temperature
difference between the battery and what it's sitting on.


Because the temperature of your hand, *unlike that of the battery*, is
determined by the balance between internal heat production and external
heat loss.  You're feeling the greater rate of heat loss from an object
(your hand) which is kept much warmer than its surroundings.  In the case
of an object with no significant internal heat production, this will
affect how quickly it comes into equilibrium with its surroundings (if
it started out not in equilibrium with them) but won't affect the final
temperature.

For the same reason, windchill affects whether you will freeze but not
whether water will freeze.