1990 Lebaron 3.0, problem with charging circuit

Dec 24, 2007 4 Replies

drained one battery already. Installed a new one, but am only reading



11.8 volts while car is running (12.2 while car is off). There's about
60 milliamps of drain between negative cable and negative battery terminal (obviously while car is off). I think this is normal, but regardless this isn't the problem. I imagine it could just be the alternator. I had a problem like this some time ago, and it turned out to be a fuse (some part of alternator circuit?). I checked every fuse, even with a continuity tester, so unless the fuse box is messed up, that isn't it. About a week ago, I left the lights on for about an hour. It started back up, and I raced it around town for ~1/2 hour to charge it back up (bad idea? Should have just left it idling?). Don't know if that has anything to do with it. Perhaps a little before that time, or after, can't remember, the meter on the dash was reading a bit higher then normal (I guess a volt or 2?). Prior thanks for any suggestions.

I just remember that my started is also prone to flake out. There are times, albeit rare, when it won't disengage. Thought maybe the problem was in the starter...

Although I do not know what is the nominal spec for this vehicle, 60mA residual current draw with everything off seems at least 3X what it should be to me. Obviously, this is not the root cause of a dead battery if left overnight though.

If you have already replaced the battery and the NEW battery is only putting out 12.2V with the vehicle off, then I'd either suspect you received a defective battery, have a bad connection at the battery, or more likely you have a bad alternator.

Bob

ntinuity tester, so unless the fuse box is messed up,

Pull the alternator and take it to the parts store and get them to test it. Most likely this is your culprit. It may have been on its last leg already and charging the dead battery back was enough to push it on over in to the grave.

Steve B.

yep, bad alternator. Got a junkman's unit for 40$. Measuring 14.6 volts across the battery now. I guess it's doing it's job.

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