Quote:
Originally Posted by AKCJ
Flash - I thought that if you measured the battery voltage with engine off, then measured it with engine running, you could tell it the alternator was putting out a voltage higher than the battery. Isn't that how the battery gets charged? I don't get why you have to measure alternator test voltage at the alternator and not the battery.
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The only reason you would do that is to determine if the battery cables are no good. You can also measure the voltage drop of the cables directly by just putting one probe on the battery post and the other on the respective target (ground for negative cable, alternator output for positive). Zero volts is unrealistically ideal, more than a couple tenths of a volt is bad.
Just for fun, I had the field winding fail in mine once, and coincidentally, a trace inside the instrument gauge to the charge lamp fail at the same time. Had to solder a jumper to repair, in addition to getting a new alt. What are the chances? Easy quick way to check the charge lamp circuit is to ground the ring terminal...the light should light brightly.