Battery/Alternator Problem
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Joined: Jan 2004
Posts: 51
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From: Edwards CA
Battery/Alternator Problem
Ok I just replaced both my battery and alternator, I started the vette and to make sure all was good while the car was running I disco the battery and the car still ran which means the car is running off the alternator
good thing. Two weeks later (today) my battery died how does this happen? The car is running off the alternator while it is running so it SHOULD be charging the battery, but obviously it isnt, any one know what may cause this and how to fix it? My guess is wires.
good thing. Two weeks later (today) my battery died how does this happen? The car is running off the alternator while it is running so it SHOULD be charging the battery, but obviously it isnt, any one know what may cause this and how to fix it? My guess is wires.
Le Mans Master
Joined: Apr 2004
Posts: 7,106
Likes: 38
From: Newark DE
could be a few otions to look at.
1. battery drain from a faulty circut somewhere
2. regulator problem
3. alternator problem
it is possible to check a charging system and get indication that everything is fine but the alternator still may not be charging correctly.
If you have a bad diode bridge it wouldn't charge the battery correctly.
take the car to a place that can do a charging system test such as AutoZone, or places places that offer a charging system check service. They can check the actual diode pattern of the alternator and this may show one or more shorted diodes and if so than this is not charging the battery the way it should.
This won't show up typically on a simple voltage check (or unhooking the battery to have the car run off the alternator only)
1. battery drain from a faulty circut somewhere
2. regulator problem
3. alternator problem
it is possible to check a charging system and get indication that everything is fine but the alternator still may not be charging correctly.
If you have a bad diode bridge it wouldn't charge the battery correctly.
take the car to a place that can do a charging system test such as AutoZone, or places places that offer a charging system check service. They can check the actual diode pattern of the alternator and this may show one or more shorted diodes and if so than this is not charging the battery the way it should.
This won't show up typically on a simple voltage check (or unhooking the battery to have the car run off the alternator only)
Burning Brakes
Joined: Aug 2005
Posts: 1,126
Likes: 0
From: Hudson Falls, N.Y. 76 Vette Modified L-48
Same answer as always...something is drawing power with the car off...with key off, put amp meter between bat cable and post and see if the meter shows amp draw....pull fuses until draw stops...find out what devices are on that fuse and fix it...
Race Director
Joined: Sep 2002
Posts: 10,362
Likes: 5
From: San Diego - Deep Within The State of CONFUSION!
Originally Posted by kb2fzq
Same answer as always...something is drawing power with the car off...with key off, put amp meter between bat cable and post and see if the meter shows amp draw....pull fuses until draw stops...find out what devices are on that fuse and fix it...
It's just a matter of going through the circuits and taking the time. When you are checking for current draw, pull the bulbs out of the interior lights because they'll be drawing power too.
Le Mans Master
Joined: Jan 2000
Posts: 8,918
Likes: 27
From: New Hill NC
True, but all circuits are not fused and this method will not find all the potential problems. One with is a common draw that will not be found this way is the alternator itself. What concerns me is the fact that the alternator and batter have been changed so many times. It would indicate to me that there is a serious draw that, one kills the battery, and two stresses the alternator each time the car is run. The most common draw other than the alternator itself is the courtesy light delay module. That is unless there are some aftermarket accessories that are present and not wired correctly.
Last edited by wombvette; Jul 1, 2006 at 04:53 PM.
