Heres the background. One year ago I had a new alternator put in. TOday while driving my battery light started to flicker (during higher RPMs it seemed like). Also, my radar detector told me that I had High Voltage with a series of annoying alerts. WIth these symptoms, I think it is either the voltage regulator and will need another alternator (under warranty) or a new battery( I lean away from this because of the high voltage).

What do you trusty orgers think?

 

I would think alternator as well, but I'm no mechanic. If you have a volt meter, measure how hight the voltage is getting. A battery can only give 12V. I never seen a battery that gives more voltage a sit goes bad. If you're gettign more than the 14 or so volts when running, I would think the regulator died.

 

I'd hook up a volt meter and see what you're getting. Anything over like 14.2 volts, your voltage regulator is dead, and you should replace the alternator so you dont fry the wiring harness.

 

brought it in today and the battery and alternator checked out as NORMAL. Happened once more today but car seems to run ok? Any other things that this strange symptoms could be guys????

 

I'm still thinking alternator. When the problem happens, how long does it last? Also, was it acting up when they tested it? If you do have a volt meter, maybe you somehow hardwire it in somewhere inside. Then you can see what the voltage is going when it does act up.

 

ok so the voltage fluctuates from 13.8 to 16. It hits the 15 or 16 when the battery lights starts flashing. IT does not usually last for long. i have brought it in to get a charging system check many times and its normal. Some days nothing happens, others it happens often....

Maybe a short somehwere?? any ideas aside the voltage regulator?

 

it wasnt acting up when they tested, any of the times.

 

Bumping this old thread because I have been searching and can't really find an answer to this issue

Ok, so I recently found the top wire to alt wiring harness was corroded and broke off. The alt itself was replaced in December. I rewired the harness and connected everything and it appeared to be running fine. Check the voltage at the battery terminals, 18V. WTF. So i cut the car off immediately, check to make sure everything is plugged in all the way and start it up again. Check voltage, 14.4V then 15 seconds later it jumps to 19V. I cut the car off again. I figure my voltage regulator is gone so I go to autozone and have them give me a free alt under my warranty. Swap out the alt and same issue. Not sure where to go free here. I've checked for continuity from alt wiring to battery. The Battery and brake light are not coming on in side of the car. Is the battery ruined and contributing to this problem? Any other ideas?

 

I doubt the battery is part of the problem of the excessive voltage. Check the two small wires going to the alternator. Both should have battery voltage with the ignition switched to on.

If you do find the proper voltage, jiggle the harness a little and see if you can get it to drop.

 

both wires have voltage. I checked the battery voltage with the car in the on position, 12.5 V. I unplugged the connector to the alt while the multimeter was still on the battery terminals and the voltage jumped to 14.x volts. I plugged it back in and it stayed. I checked a few min later and the voltage was 13.7 V. I'm pretty sure the battery is gone but not sure if its part of the problem

when i started the car the voltage was 17V this time

 

I don't think there is anything wrong with your battery. I have a red top and it sits just above twelve volts nominally. If it still starts the car, and holds a charge, it's fine.

Try looking at the ground to the alternator. If there is resistence in the ground, it could cause a voltage above the negative battery terminal to develop on the ground of the alternator. The alternator then tries to go 14 or so volts above this false reference, causing a higher than normal output.

[EDIT] Oops, I misread your signature. I thought you had an Optima Battery. Either way, nominal voltge should be between 12 and 13. (2.1 volts/cell * 6 cells = 12.6 volts)

 

the battery voltage is all over the place. Right now its at 15V with the cable disconnected. I'm gonna get it checked when i get a chance

 

Check your belt tension. as the engine speeds up, and if the belt is loose, it will actually UNDERCHARGE the battery because the belt is slipping on the pulley.

 

Apparently my alternator wasn't grounding itself thru the housing well. I added a ground from to the chassis and the voltage stabilized. Also, the battery was bad because it running at a high voltage. I bought a new battery and added some grounds, problem solved