Alternator Workshop - New Alternator Overcharging

Hi folks,
My old alternator went on me in catastrophic fashion, which is another story all together.

Ordered a Bosch reman, with pulley and installed 2 weeks ago.
Ran fine until this weekend. On a 12-hour roadtrip, it started throwing the 'Alternator Workshop' warning and occasionally flashing the battery light.
It wouldn't stay on, and would randomly pop up while at 2100rpm doing 110km/h. Not under load or accelerating.

Got it to a midpoint, picked up a multimeter, everything tested ok.
Battery was 12.6v with car off, alternator putting out 14.2v, battery reading the same while running. Checked belt tension, pulleys, seemed fine.

Set off again, make it 2 hours, warning comes on, pull over, alternator reads 14.4v output. Turn off car, wait a few minutes, runs fine the final 3 hours until I'm home.

I'm going to swap the alternator and battery under warranty tomorrow, and will check the grounds as well. Any other gremlins i should be looking for?

Thanks.

14.4v may be on the high side of normal, but normal. Battery cells in good health should show a bit over 13v at full charge and your alternator input seems about right. I'd tend to suspect a failing battery.

Bad/weak batteries ruin perfectly good alternators.

thundershorts said:

Bad/weak batteries ruin perfectly good alternators.

Click to expand...

Yup....