Battery not charging but car runs fine if jumped

wessock · Post by **wessock** » Sun Mar 18, 2007 3:54 pm

On the way to work my car starts quickly and all electronic things work as they always have. On my way out of work, the battery is completely dead. Nothing like headlights were left on or anything either. I did notice the airbag light was on now so my first thought was maybe a bad sensor was draining the power. So I get a jump and the car starts and runs fine for the 45 mile and 1.5 hour ride home. When I turn off the car and try and start it right away, the battery is dead and the interior lights are very dim. Ok, so now I'm thinking it's just a bad battery. No sensor would drain it that quick. I ruled out the alternator since my ride home was smooth. So I let the battery charge over night in a charger to make sure. Well the battery seems to have charged and I started the car several times with it re-installed. The airbag light is still lit while all other lights go off after ignition and work normally. I checked all of the fuses, the battery connection seems to be fine. Any Ideas? Is it something between the alternator and the battery or would the car not run? Since I took the battery out and charged it, then put it back in, everything seems ok. I don't want the battery to slowly keep getting drained though and be stuck someplace.

delphis · Post by **delphis** » Sun Mar 18, 2007 4:56 pm

first off I would check all your connections like the grounds and connectionto the altenator are tight and on good bare metal. Also if you have an amp make sure that the remote wire didn't come lose because if it did the amp is staying on while the car is off and drainging the batterey.

wessock · Post by **wessock** » Sun Mar 18, 2007 5:35 pm

No amp or anything like that installed. Any connections I can easily get to look fine. If it was a ground, wouldn't it cause problems while driving too? I don't know much about electronics though. While driving the lights don't dim or anything like that. Is there a wire that goes directly to the battery from the alternator for charging? It's hard to trace it all the way.

Spider · Post by **Spider** » Wed Mar 21, 2007 1:00 am

wessock wrote:No amp or anything like that installed. Any connections I can easily get to look fine. If it was a ground, wouldn't it cause problems while driving too? I don't know much about electronics though. While driving the lights don't dim or anything like that. Is there a wire that goes directly to the battery from the alternator for charging? It's hard to trace it all the way.

Hey Wessock,

Yes, the alterrnator has a heavy wire attached to it. Thats a positive wire that goes to the battery.
It should be ok. But it could be loose.
Disconnect the battery ground cable (at the battery) before you check it tho.
Also, make sure your alternator drive belt is ok ? (tight?)

Your battery may be going out or you may just have a bad "ground" someplace.
Take the battery to a auto parts store that "load-tests" batterys.
Do you have "Auto-Zone near where you live ? They test for free.

You can test your charging system yourself with a digital-multi-meter (available at any auto parts store) just set it at 20vdc and put the red probe on the positive (+) post and the black probe on the negative (-) post of your battery.
With the engine not running ?. The meter should read at least 12.5 (volts)

Now, start the engine and look at the meter (same setting,20vdc) you should see at least 14.0 volts at idle, higher is better.
If still in the 12 volt range with the engine running ? Than speed up the engine rpm's, Call your helper and try this with the headlights off and try it with em on.
The volt reading should go up to at least 14.0

If they don't ? You have a charging system (alternator) problem.
Or,
a loose wire, ground or positive.
Or,
a battery that won't hold or take a charge.

Hope this helps,
keep us posted.

P.S.
wessock also wrote;
____________________________________________________________________
" Since I took the battery out and charged it, then put it back in, everything seems ok. I don't want the battery to slowly keep getting drained though and be stuck someplace."
______________________________________________________________________
(Does this mean the airbag light is no longer on ?)

va3dwo · Post by **va3dwo** » Thu Mar 29, 2007 9:34 pm

I had the same problem and it was the positive from the battery to the alternator, bolt was hanging on by half a turn.