Craddock

Today was the first day this year that it snowed any decent amount, and a charging problem decided to rear it's ugly head. I have no idea how to go about this, but I'll jump at anything to fix it cause I'm not leaving me, or any others riding with me freezing if it fails for some reason.

So, here's the details of it:

Car normally runs at about 13 volts on gauge.
Car normally runs a little lower on volts on the gauge on the radar detector (plugged into cigarette lighter).
Usually when it's cooler outside (below or around 50) it runs a higher voltage.
Today when it got really cold and snowed, it was running anwhere from 10.8 to 12.2 volts on the gauge in the detector, running from middle marker to red on the regular gauge.
If you're stopped in drive, it drops slowly to about 10.8, then jumps up pretty quick for a little while, to about 11.8-12.2, then drops again.
If you put it in neutral, the car jumps back up to 12.2 and stays steady.
*Note: One of the pulleys under the hood has been squeaking until the car warms up here lately, possibly the alternator. I tried looking but not able to tell which one it is exactly.

Any ideas?

Guest47904

Are these readings from the interior gage or some other device?

Are you actually having a problem or just noticed these readings? Have you witnessed the readings as you remove/add loads such as head lights, HVAC etc......?

How old is the battery?

Have you ever removed, cleaned and retightened any of the connections either frame to engine, positive battery cluster, negative cluster or at the battery?

What is the actual readings across the battery before starting, during cranking and after the engine is running? This can give you the best picture of the health of the charging/starting system.

Incidentally, 2 things are working against you as a battery ages. The first is internal resistance is rising. The other is, output decreases as temperature drops. I think, don't quote me on this but for every drop in a degree C, the output drops 0.1 volts. I can't quite remember.