Re: battery drain while parked - why?

["Paul C. Waterloo" <74543.407@compuserve.com>]

My old 87 5KSQ seemed to have the same problem with the battery draining.
Never troubleshot it. However, I would have to say that there is some
leaking circuit somewhere.

One way you can determine if the battery is leaking, is to disconnect the
negative lead at the battery with the ignition off, and reconnect a ammeter
in series (bridging the negative terminal to the negative cable) and
measure current flow. I imagine it would be something measurable on the
0-10 amp scale.

If it leaks at a rate of 1 amp, it will discharge the battery 24 amp-hrs
over one day. Two days, 48 amp-hrs. I can't remember how many amp hours a
car battery is, about 85-100? If so, and you have 500 ma leakage, leave
your car for four or five days, you'll have a battery that won't be happy,
especially if it is old and tired.

One of the circuits I have always suspected was the field excitation
circuit for the alternator. It has diodes in it, they can leak over time,
and those damn alternators on the 5K series hang low and get wet and junk
all over them. These can all result in leakage paths.

The alternator was a problem on some MG's that I have troubleshot in the
past.

Maybe it's just the Audi Gods.....nobody knows.

Paul

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Paul Waterloo
Brookfield, IL

91 200q

EMAIL: 74543.407@compuserve.com
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