OK well im a vette newbie i have had my white 1993 for about a month now. Things were great. I won my first award and could not be happier with my new toy. Until!!!

I was cleaning out the car and must have pushed the interior light switch on, which i did not notice until the next day when i went to get in for a ride and it was dead. I jump started a dead battery (before i read that that is not a good idea) and all was well until a day or 2 later my battery gauge started pegging out at 18 volts were the dash lights would flicker and warning lights would come on. this was a random event however, it would peg to 18 for a brief moment then go back to normal then after a bit peg again. i was told it was the voltage regulator so i disconnected the battery and took out the alternator. i took it up to a local alternator shop where they tested it and said all was working properly. since i was there i had them replace the voltage regulator anyway. I got the alternator back in took it for a spin and it pegged at 17.8 volts once on my drive and it has not done it again until today. It has been running fine for the last week or 2 since i replaced the regulator then today as i was driving it started to creep up in volts. Now instead of just quickly pegging out at 18volts it gradually works its way up to the 18 volt range where it sits for a moment or 2 then goes back to normal for a bit then goes back to 18volts. I dont know if its the alternator, battery or a loose wire.
If anyone can help i would greatly appreciate it.

 

I would check all connections. It can't be the battery IMO, it could something in the voltmeter on your car.

 

Measure the battery voltage when the dash voltmeter gets to 18 volts. My money is on a defective dash voltmeter.

 

....i think that the next time this happens, in spite of what the volt meter reads on the dash, physically grab a volt meter and measure the votgage both at the back of the alternator and at the battery....