My s54 will not charge. Need help ASAP

[Vrossi46]

just did my s54 e30 m3 swap and it started right up, but it will not charge.
it is also getting very hot, like 120 degrees celsius.
The indication in the cluster is working as it should, the charging light turns off.

Could it be just the regulator that is broken, or could it be the dme that control the regulator?

[FredK]

What is your battery voltage with the car off? It should be around 12.6V. What is your battery voltage with the car running? It should be around 14V or so. If it isn't, try unplugging the DME control plug on the back of the alternator and see if that changes voltage. If it changes, DME control circuit is suspect.

The alternator must be putting out maximum current to get to 120°C.

[Vrossi46]

Hi
The voltage on the battery is around 12,3-12,5 v. when it is running is almost the same, only when i rev it to 2000rpm or higher the voltage is 13,6. The alternator is getting very hot in few minutes.

i will try to unplug the dme plug and check it.

[Vrossi46]

When i started up the voltage starts on 12,3 and slowly bilds up to 14v.
when i unplug the dme plug it only stays on 11,8v.

[FredK]

The battery sounds like it's in decent health voltage-wise. If you have the time, you should probably load test the battery and alternator to determine which one is bad. I would also see if cleaning the main engine ground strap does anything. The alternator is seeing quite a large load from something and it could be something as simple as a bad ground.

[328ijunkie]

Alternator have switched power?

[Vrossi46]

Sorry for late replay.
It turned out to be the alternator it self that was in bad condition.
Replaced it and all ok. ;)