Should charging volts drop when headlights on?
 

I recently installed a voltmeter gauge after experiencing some electrical problems and I've noticed that when I turn the headlights on the charging voltage drops from approx 14 to 13.5 volts, and when I turn on the fogs it drops a bit more. Is this normal?

Yes. As the load increases the voltage tends to drop. As long as you're running at least about 12v you'll be fine. If it gets lower you can harm your alternator.

John

Normal.....

Thanks for the quick responses! I've just become a nervous-Nelly after having what I think was a bad Optima. The battery wouldn't hold a charge and was replaced for free under warranty (batt. was 6 months old). I installed one of those fused battery disconnects and I use it almost every time I park the car for more than a day. Lately, the tach has been bouncing a tiny bit (pulsing) and this now has me nervous...

Bouncy tach is because of ?? I missed that one.

All normal. I disconnect mine if longer than a day or two. Same volts with the lights. Even lower with the air on high.