I was driving in stopped traffic at night when car died and would not start. knew it was electrical, but had no way of charging battery. Jumped car the next day (during daylight)and the car was driven home 20 miles with no problems. Took car to Autozone to have battery/alternator checked out. They said battery was good but the alternator was bad. My question is, I'm showing anywhere from 13.2 to 13.9 amps on the computer info while car is running with a/c full blast and lights. Is alternator really bad!!!!!. Seems as long as I'm above 12v I should be ok. Anyone know for sure - Thanks

 

13.2 to 13.9 volts is correct, but it could have a bad diode and still produce good voltage.
Still i would get it tested somewhere else before purchasing an alternator.
Also check your cables for corrosion.

If you have any further questions please include year, make and model.

 

Thanks - FLCADDYTECH - Battery was tested and was bad. Obviously. battery wasn't holding the charge. One more question. If voltage drops below 13 is Alternator still having problems? or does voltage drop into the 12.s when everything is on.