Author Topic: Battery problem (Read 4074 times)

e30arm · « **on:** February 10, 2010, 10:16:44 AM »

Hey guys, in the past 6 months I have replaced my battery twice. For some reason the battery wont hold the charge. I've replaced the alternator, but still having the same problem. Any ideas?
btw its a 91 318

doitover · « **Reply #1 on:** February 10, 2010, 10:26:59 AM »

possibly a current drain of some sort draining the battery? Try measuring the current from the battery with the car off. I don't know what the stand by is but it should be 10's of milliamps I would guess.

If it seems high, start testing individual circuits at the fuse box.

e30arm · « **Reply #2 on:** February 10, 2010, 10:32:58 AM »

I just did, its shows 12.
however, in few days its goes down to 10.
Also when I start the car, and unplug one of the battery cables, it dies right away.

dvmotorsports · « **Reply #3 on:** February 10, 2010, 11:36:59 AM »

Like doitover said, you could have a parasitic drain. It's possible to back feed through the starter/alternator as well, and that is harder to detect. Or perhaps you just got unlucky and got two bad batteries in a row.

doitover · « **Reply #4 on:** February 10, 2010, 09:35:01 PM »

You want to check the current, not the voltage. There is always some standby current but it should be pretty low.

e30arm · « **Reply #5 on:** February 12, 2010, 03:32:39 PM »

Thanks your for advise
I will check it...

e30arm · « **Reply #6 on:** April 04, 2010, 07:00:57 PM »

still can't figure out the problem
when I start the car, and measure battery, the voltage is less than when its off. So I am assuming the alternator is not charging the battery. I tried dissconnecting the battery cable while the car was running, and it died on me immediately.
New battery and alternator were installed. However, the problem still exists.
Also there is a shortage, that drains the battery. It lasts for about a week.
This problem never existed till I replaced the alternator.
Please Help!

Ryann · « **Reply #7 on:** April 04, 2010, 08:14:52 PM »

A volt meter connected to the battery should show between 13 and 14 volts while the car is running. If it shows less then your alternator is not charging the battery. This could be because the voltage regulator in the alternator is not getting voltage from your ignition like it should and thus not "turning on". Check the smaller connections on the back of your alternator and make sure all the wires are tightly connected & where they should be. Also check for resistance (ohms) to ground (-) from the alternator body itself. An alternator must have good + AND - connections to the battery to work properly.

e30arm · « **Reply #8 on:** April 21, 2010, 08:32:26 AM »

Just want to thank everyone who tried to help
I have fixed the problem
one of the wires from alternator wasn't tight enough.