Alternator overcharging question (cheeky E46 question)

[Adil786]

Need some advice please!

Went back to my "winter car" this weekend, which had been parked up for a few months. Have been turning the engine over every few weeks to keep things running but this weekend the battery was dead. I just bought a new battery after thinking it was 8 yrs old and knackered after being run flat a few times...

Have replaced with a new bosch S3 70AH battery (note orig was 55AH).

BUT........

The alternator is now overcharging and keeps blowing my headlights and making my dash look like a christmas tree

Car is a 318i, 2002. There were no battery or alternator issues before I parked it up.

Is this just bad luck that the regulator has gone, or could have replacing the battery triggered something or have i just not done something obscure?

[bss325i]

Need to carry out a test of the battery and also a check on amps the alternator is charging at.

[Adil786]

the alternator is overcharging at something like 17v (above 2.5k rpm).

I just didn't have this problem before I parked the car up I'm just thinking i might have killed it by putting the bigger capacity battery in - doesn't make any sense in my head how though.

[MJJ_ZX6RR]

Sounds like the alternator's regulator pack has failed. I am sure the larger capacity battery is fine.

On my E32, the regulator pack was only £12 from GSF, and a leisurely hour to fit. Not sure if the E46 versions are substantially different.

Martin.

[Adil786]

cheers, i wish it was that cheap! bmw are looking for £90 for the regulator pack. i can get a refurbed alternator for £120! gsf/ecp no regs seperately

anyone know any good suppliers of regs?