Battery light on

Hello,

The battery light on my 98CV always comes on when I start the car after sitting all night. After driving for about 15-25 minutes, it goes out and usually stays off after that.

Its been going on for about a year or so. The battery is only 2-3 years old and I just had the alternator checked today and it was almost 15 volts. No other problems, just the light is annoying.

The meter doesn't move, it is solid in the center.

Thank You for any assistance.

weak alt. turn on everything electrical and test it

Hi - i have the exact same problem 99CV. Ive had it happenign for a few monthes now - and just recently while driving at night the lights just went Out (fun) - the car kept driving but lost all lights - made it limping home. Took battery into apartment and slow charged it with battery charge. Did that till next day and it was all charged up - now i notice that the battery reads 12.5 or so when sitting - but when car is idling its only 11.5 ! So that leads me to believe its the alternator - but frustrating since this is a rebuilt nice quality alternator only about 1.5years old - and i believe i had the same issue back then when i replaced it.
Anyone have any other ideas? Ill bring alternator in for test tonight - but somethign tells me its a different drain on teh system.
Also - im worried as ive read online that the alt can catch on Fire if the battery is really weak (as it will over work itself).
My suspicicion is that somethign drained the battery and this in turn made the alt work too hard and so killed the alt but the original problem (slow battery drain) is still there.
Guess ill put new alt in and then hunt methodically for battery drain - i guess pull fuse one by one and see if drop in battery (if there is one) stops.
Anyhow - any suggestions/wisdom appreciated

Put a voltmeter on the battery then rev and hold the engine above 2,000 RPMs then turn everything on, radio, windshield wipers, headlights, hold down the brake pedal, wait for the radiator fan to turn on, etc. the volt meter should stay at something above 14 volts, if the voltage continues to go down as you turn things on the alternator is bad and needs to be replaced.

If the voltage is staying above 14 volts you have a wiring problem that needs to be addressed, follow the wiring from the alternator all the way back to the battery and clean up and seal every connection that you can find including the battery cable clamps.

Check the little wire on the alternator. If the connection is loose there, the light will come on.

This may be a long shot, but this might also be a symptom of an electrical short of some sort or a device that is drawing electricity when engine is off. If the car was previously a fleet vehicle (police, taxi, etc.) they may have left something behind that is drawing power overnight causing the low battery voltage.

Since it charges back up to normal charge after 15 minutes or so, I would venture to say the alternator is strong and is not the problem.

FWIW, I just had to replace a 2 year old battery 2 months ago in my MGM. It suddenly had a dead cell when I went to start after filling up at a gas station. So even though the battery is newer, doesn't mean it's not faulty.