I have an alternator that's supposed to put out 100A. I tried to move
it the other day (haven't driven it in a while), and nothing worked. No
battery juice, etc.
I finally got it jump started with great difficulty, and noticed when I
activated teh power locks, there was a short time when the fuel pump
stopped making noise, and then started whining again. (Like the power
So I take it to Autozone, and they show my battery/charging voltage a
little low (I saw that in the gauges), and the alternator only putting
out 53A. Are these alternator brushes easily replaced? And is there a
built in regulator or is it elsewhere?
But one question that bothers me... The fact that there was NO juice on
the vehicle. I found no lights on (after I got it running again), no
doors ajar, no under-hood lights on, nothing! Is there something that
is some usual thing that will drain a battery on this vehicle?
I have a battery charger for deep cycle marine batteries, but am unsure
if I can charge this normal auto battery with it. Does anybody know?
Anyone can correct me if I'm wrong, but I'd be willing to bet that the 100A
rating is not sustainable. A car battery might not be able to charge that
fast and even if it could, all the accessories would take away from that
At the very least, I've never been able to get any car battery to charge
If the battery was (dead, dead) dead, the alternator may not have been able
to remain biased. (AFAIK all alternators require a battery for this purpose,
as well as filtering the output.) This could have caused a momentary sag or
dropout on the electrical system.
See above. I doubt the alternator can sustain 100A or even close to that for
any length of time. What you say really sounds "correct" to me.
A defective, sulfated or shorted battery could drag down the charging
voltage. Any of those problems could be likely especially if the battery was
A) old and/or B) sat discharged for a long time. Try again with a better
battery and see what happens.
I think the regulator is integral to the alternator, but that could be
Dunno about this, but see above. The alternator requires a *good* or at
least not totally junk battery to work properly for at least a sort of
buffer/filter. If it was carrying the load exclusively or close to, the
regulation and output may have been off, which could prevent things from
You can try it, but A) car batteries aren't really deep cycle batteries and
B) the battery is probably already shot. Try another and see what happens.
Bad batteries can cause screwy behavior and it's pretty easy to try another,
so give that a shot. You may solve all your problems.
William The Guesser
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