97Supra

This problem is actually on my Maxima, not the vette, but I figured someone here could help. The battery has been dying on us every now and then. I originally assumed it was the alternator and went and picked one up (haven't installed it yet). Today the battery died again and we had to jump start it. But after 20 minutes of driving, the car started fine....which leads me to believe the alternator is doing it's job. I put a voltmeter on the battery and I get 12.2X volts with the car off, and about 12.3 with it running. Stabbing the gas will cause the volts to go up to about 12.5, but no higher. Based on that info, can anyone tell me anything that might help?

Thx,
Jason

Aggravated4life

Its tough to say without doing more checking,but usually if the alternator is draining the battery,youll also need a new battery.If you had to charge it up a few times,consider it dead.It wont hold a charge anymore.

Also,Its always suggested to have a good battery or full charged battery when replacing the alternator.
If the alt. seems to be doing its job,replace the bad battery with a new one or youll keep having to jump start or charge it again later.

However,your voltage you showed seems low.
Most cars should be in the 13-14 volts range when running and fully charged.
:)

97Supra

Thanks for responding so fast. However I forgot to mention that when this started happening the battery was the first thing I replaced. I thought that had fixed it, but the same thing started happening again two weeks later.

Thx,
Jason

PeteL

Charging voltage seems very low. I think your alternator has seen better days. It should be above 13V at 1500 to 2000 rpm.

Put a good charge on the battery (long slow charge for over 24 hours) and install that new alternator.

Rick Williams

I just had the same problem with my vette... 12.6.volts running.. Replaced the alternator.. now 14.3..

VetteNoob

Ive had to recently replace one too. Definitely sounds like a weak alt killing your batteries. Replace the alt, charge the battery and you should be good to go unless your new battery is toast too.

jfb

Your alternator is definetely on strike! Engine running, the battery voltage should be 14.7 volts cold and no lower than 13.2 volts hot. Install the alternator and charge up the battery with a charger. It is hard on alternators to fully charge a discharged battery.

R23HTC

It could also be some badly corroded wires or a loose connection.

97Supra

Thanks for the help guys. New alternator is in!

Jason