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DIY alternator test to check for bad diode?

Hi Randy,

The car boards are a good place to find electron flow mysteries and plenty of advice, both good and, well...

Are you pursuing a battery drain issue? You think it is the car? Normally, I start by removing the negative clamp from the battery post, and inserting a small lamp in series. Any parasitic load capable of killing a good battery in less than two weeks will light a lamp like you'd find in the glove box.

Then the question becomes one of finding that load. Just like looking for a leak that has your water meter turning when all the faucets are off, you need to divide the paths. The alternator path is most easy to divide by removing the B+ wire at the alternator. Put your bulb in series there.

I always start with a bulb instead of a current meter, just in case the drain exceeds the rating of the meter's shunt. Hastily made current readings with a meter can have a long and possibly expensive learning curve.
--
Art Benstein near Baltimore

Ohm my God, that was bad. Watt made you tell that joke?






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New DIY alternator test to check for bad diode?
posted by  rstarkie subscriber  on Sat Oct 10 06:15 CST 2015 >


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