[GTLEGEND]

Originally Posted by bucknbuzz

My mistake, it seems it does have something attached to the negative terminal which I now take to be the BMS, was never aware of it and never noticed it in the past. This morning I attached the multimeter to the car, started it and got the revs up. At idle, the battery continues to slowly drain, no charge. At 1500rpm the battery does charge little by little. @ 2000rpm it charges a bit quicker but it took a few minutes to get from 12.21v to 13v. So, battery is holding charge so can assume is still good, alternator is working, battery is charging, albeit slowy. Turned A/C on, very slight drop in battery v, not an issue. turn lights on, battery V drops noticably then settles when revs increased. Dying diodes on alternator? Can you make sense of this?
thanks for your reply re the BMS, never knew of it.
cheers
B.

Sounds like its working normal to me. Suggest leave lights on for 20 mins or longer when car is turned off to drop the battery state of charge below 80% which would only drop below if you don't drive the car often. Then start and see if the alternator charge rate is up.