moondance

What is the output range I should be seeing from my alternator? I kept seeing it drop to the red when sitting at a light with the AC on so I decided to check it. When I first start the car its 14v+ but after the car heats up and reaches operating temp it will start dropping. Seems to hover right at or below 13v until the fan kicks on then it will drop to like 12.6 at the alternator. All this was checked with the car in gear and running to simulate sitting at the light. Granted when I start running down the road again according to the gauge it comes back up to 13ish. Seems kind of weird that it drops so much after it heats up. Any help is appreciated. Thanks.

n2ceptor

At first start up the battery is cold and low, the alternator has an internal regulator that will boost output to the battery...

At normal idle, the reading at the battery, with a multimeter, should be around 13.8~14.2 volts... With all acc. on (IE: radio, A/C,etc.) the reading may be around 13.2~13.5..

You can't really get an accurate reading with the factory guage...

moondance

Right but mine reads lower than 13.2 with a multimeter after the car is hot and such. I am trying to figure out why it would drop to between 12 and 12.6 after its hot

97FormulaWS-6

The regulator inside the alternator maybe on its way out.

Do you have a stereo or any other drain on the electrical system besides the car itself?

moondance

yeah when it drops while in gear and at a light the AC is on. Sometimes the raido too but mostly the AC.

n2ceptor

Have you had the battery load tested????

moondance

Its a new battery.