1990 Lebaron 3.0, problem with charging circuit

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.