Help! Battery isnt charging when starting!

[wtrueman]

easy check for alt.

This is easy to find out if you have fried the alt. With the motor running, take one of the battery leads off the battery. If the car stalls, the alt is dead. Wayne.

 

[philm]

True(manwayne), but if it doesn't stall, it could still be bad. I've seen them run on one dead diode. Although, 95% of the time it's a bad slipring brush.

 

[Turdle]

+1
Wifes nissan alternator worked--unless the headlights and blower were running. It had only 13.6 charging volts output, and tested fine at oreillys. I made them warranty it anyway after showing them the battery light glowing when the ac and lights were on. You should have at least 14.5v at idle with all accessories running.

 

[Liska]

When the alternator on mine went, it took the battery with it. We did the classic test, put it in, crank up the air, and watch it stall. Replaced both, had no problems after that.

 

[marragtop]

Bottom line... never take a 2nd look at an alternator without disconnecting the battery. A millisecond of charge can give you a huge problem.