Ok, I'm sure this has been posted a couple times, but this is something I need to fix asap, as this is my only car. Yesterday, my battery was dead when I went to start it. I charged the battery(2 months old) and it went fine. About 20 minutes later, the voltage dropped from about 13 volts to 10. within 5 minutes, the volts started hover above 8, without the stereo, a/c, any accessories going and they would not raise at all, and when I parked it, it was completely dead.

I charged the battery today until full, and the car's done it to me twice today. Would it be possible it could be something else? TIA for any help.

 

Easy way to check the alternator is to get the car started (jump it/push it) disconnect the + battery cable if the car continues to run it s not the alternator.

If it still runs I'd look for a short

 

Just died doing that.

bump btw.

 

Time for a new alternator.

If all your connections are good.

Check all the grounds first, clean and not corroded, if I' m no help try the search

best of luck

 

Hmmm, think it could possibly be a bad voltage regulator? Looks like either way I'm buying and slapping on a new alternator tomorrow and seeing if that'll do it.

 

Wait, be careful with that test. Pulling off the + cable will also disconnect the alternator. Why? Because the alternator is connected via piglet connector on the + cable!

So... Considering that it's two bolts, remove the alternator, head down to your local auto parts store, and ask them to test it for you. Most parts stores will do this free.

PaulC

 

This is not a good test.
The battery acts as a power filter for the car. If you disconnect it, you'll be liable to having dangerous power spikes coursing through your car's already old electrical system...NOT a good idea.
I wouldn't be trying this especially with a suspect alternator.
AND, apparently, if you were running the car and reading 8V, the motor WILL run with insufficent Voltage. But you STILL need an alternator.

Cory
Who has replaced his alternator this year.

 

Yeah, it ran at 8 volts, just no headlights, dash lights, any of that going. Looks like tomorrow I'll just yank the alternator and steal the parent's car and head to Autozone or something. Price be damned, I just need this thing running.