Don Mathis wrote:
>
> I did not drive my MGA for about 9 days. When I attempted to start it
> yesterday, the battery was dead. The battery is 2 months old. I took off
> the negative ground and placed a ammeter between the lead and the negative
> battery post. It read 128 ma. Somewhere I have a semi-short!
> Any ideas how one should logically, find this?
I had a similar problem with my '68B.
I, too, placed an ammeter in series with the battery and found
significant current drain when there should have been none.
I pulled each fuse, but there was no change to the ammeter reading.
Finally I checked the wiring diagram and realized that the
alternator was always directly connected to the battery. When
I pulled the connector off the alternator the current went to
zero! Turns out one of the diodes in the rectifier bridge
was bad. The bridge is always connected across the battery so
any diode leakage will tend to drain the battery (normally there
should be very little diode leakage, probably just microamps).
If your MGA has been converted to an alternator, maybe this is
your problem. If you have a generator, perhaps the regulator
is somehow stuck and you are pulling field current? Or maybe
there is another leakage path in that circuit. Shouldn't be
too hard to isolate.
John Hunt johnhunt@ee.ogi.edu
Senior Research Engineer
Dept. of Electrical Engineering
Oregon Graduate Institute
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