My Brat had the lazy charge going on 7-8 years ago and I replaced the alternator with a new Bosch. Few weeks ago heading to work I get excessive voltage, gauge gets into the red. I know it was for real because the heater fan speed up alot!! Before I could cut the car off it came back down to normal. I still had my old alternator so I installed it. Good for the past 2 weeks and this morning it jumps into the red again. I cut the Brat off and it will not turn over to try again. To make a long story short it is home now and starts. Voltage seems normal again. Is it possible the voltage regulator in both alternators are going bad? Or could some other strange electrical thing cause this to happen? I m ready to purchase a new alternator but want to be sure that is the problem. Thanks.

A bad battery connection will sometimes make an ALT run at high voltage (trying to "push" power thought the bad connection) but not ussually to the red.

 

But definately check those connections and the condition of the battery before thorwing money at a new ALT.

I replaced the battery cables a few years ago. Have fairly new battery connections on it that are not fuzzy, white or loose. I will throw a voltmeter on the battery but the battery is only a couple of years old. Thanks!

check the body ground wire between the framerail and the engine casing

check the body ground wire between the framerail and the engine casing

 

+1

 

this is kinda the stuff I mean.

 

There are lots more places that connect the battery to the car than just at the posts.

 

Gotta clean them all.