finet@students.uiuc.edu wrote:
:  Another possible safeguard against battery drain is 
:  to put a spare battery on the left side of the engine compartment and 
:  connect it to the main battery with a resistor(?) which I understand 
:  allows the spare to charge while you are driving but keeps it from 
:  discharging totally when you are parked, thus assuring enough power for 

That would be a diode, not a resistor.  All a resistor does is soak up
some energy and convert it to heat.  A diode allows current to flow in
one direction, but not the other.  I would expect that the diode would
go between the regulator and the second battery, rather than having a
connection between the two batteries, since you want the secondary to
charge, and provide power to things not connected to the primary.

	Dworkin