With my car at idle, lights on, stereo on my alternator charges my battery at 14.7-14.9 Volts is that a good reading? My alternator isn't over charging my batter is it? Even with lights off, stereo off it reads somewhere along the lines of 14.7-14.9. I hear anything over 15-16 Volts is bad.

 

Umm no 13.5 is what the car should read when the car is off. 14.5-14.6 is normal voltage while the alternator is running. I was researching and that's how I came to that conclusion.

 

With a new battery recently I was at low 14's

once you get to 15 I would start to worry

 

My passport 8500 informs me of around 13.7 with all the glitz and glamour going on in my car when running....at first its 14.1 but it drops to 13.7 for normal driving.

Your car should be about 12.5 volts with the car off, and just in the ACC/ON posistion.

 

As long as this voltage doesn't continue to climb over time, you're fine.