HELP battery/charging issue
Thread Starter
Intermediate
Joined: Apr 2001
Posts: 43
Likes: 0
From: ky
HELP battery/charging issue
1991 stock red vette
On the way to work this morning the red battery symbol appeared in the info display, and the volt hand dropped from 16 to about 10 or 12.
Where should I start to troubleshoot this?
On the way to work this morning the red battery symbol appeared in the info display, and the volt hand dropped from 16 to about 10 or 12.
Where should I start to troubleshoot this?
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Re: HELP battery/charging issue (russell1755)
The red battery symbol appeared because the alternator was not charging the battery and the battery was discharged badly and its voltage dropped into the unsafe range. First , you should never see 16 volts. The alternator voltage regulator attempts to maintain 14.7 volts across the battery (by design), my dash voltmeter reads 13.6 most of the time. You probably have a defective alternator. Charge the battery overnight, then measure the battery voltage in the morning with a voltmeter and compare it to the dash voltmeter. Start the engine and measure the battery voltage with no electrical equipment on. The battery voltage should measure between 12.0 and 13.2 volts after charging. The battery voltage should measure 13.2 to 14.7 volts with the engine running. If higher than 14.7 or lower than 13.2, then your alternator needs replacing. Your battery could be part of the problem too, but if it starts the car reliably, then it is most likely good.
Burning Brakes
Joined: Apr 2001
Posts: 844
Likes: 3
From: Kennewick, Wa. USA
Re: HELP battery/charging issue (russell1755)
I agree with jfb! You should never see that high of voltage. You most likely have a bad alternator! By 10-11 volts you'll start having drivability problems like blinkers that won't flash and a rough running engine! I know, I just replaced my alternator last night for the same reason! :cry
Advanced
Joined: May 2001
Posts: 74
Likes: 0
From: Kennesaw GA
Re: HELP battery/charging issue (russell1755)
Here is a good alternator test for those who have no voltmeter handy. Typically, the alternator will fail in the "not enough voltage to recharge the battery" condition. Therefore, the way to see if that is true is to merely shine the headlights at say, your garage door, when it is dark enough to see them. Have the motor running. Then turn off the motor, and see if the lights dim. If they dim, the alternator is usually ok. If they don't, it indicates they are already running on battery voltage, and they won't dim when the engine is shut off.
Cheers
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