Battery Draw

["John Teller" <jteller@domain.elided>]

Quoting Charlie McKenna:

<snip>
> I borrowed a voltmeter from a friend and hooked it up to the
> battery in the following manner:  I removed the positive cable
> from the battery and hooked up the positive lead from the tester
> to the positive terminal on the battery and the negative terminal
> from the tester to the positive battery cable.  Having done this
> I got a reading of 10 volts on the volotmeter which, I'm lead to
> believe, means that there is a 10 volt draw on the battery.
<snip>

Unfortunately, you measured a voltage drop, not a "voltage draw".  What you
were doing was verifying that there was indeed some sort of circuit
(connection) between the positive and negative battery terminals.

What you need to be measuring is the current flow from the battery while
you are isolating the circuit that is killing the battery.  Switch the
voltmeter over to DC current (measured in amperes or milliamperes -- 1000
milliamperes = 1 ampere), starting with the highest range possible.  Note
that you may have to plug the test leads into different jacks on meter. 
Connect the meter exactly as you have done, and look for a current
measurement.  If there is no visible indication, switch down a range at a
time until you see something.  Then repeat the rest of your diagnosis,
looking at the meter after pulling each fuse.

Leave each fuse out until you pull the one that drops the measurement down
a piece.  Then re-insert the other fuses, checking after each one that the
meter does not start registering current flow again.