Hi all,
I'm looking for some hints on my '05 745li's charging issues.
About 8 mos. ago I had a dead alternator, purchased a new Valeo from AutoZone and installed it. Everything was great until about a week ago when that alternator died. I had driven to a buddies and when I got out of the car I smelled burnt windings so I popped the hood and the alternator was smoking, literally! So off we go to the local AutoZone with smoked alt. and get a replacement. Got it in and its getting pretty hot, and my instrument cluster, iDrive, and sometimes a/c blowers are shutting down and rebooting. The shutdowns are more frequent with an increase in rpm and or run time, and appear to be related to battery voltage. If I let the battery draw down a bit without the engine running the car goes longer without resets. Dash voltage display indicates resets start after battery voltage reaches 14vdc. I am also seeing spikes as high as 16vdc, though on average it will run up to 14.5-15.5.

It seems like the alternator is overcharging to me but the voltage readings only seem marginally higher than normal. I tested the battery and it is fine, replaced about 12 mos ago and registered. What else is in the circuit that may cause this? Is it just a fluke that I got two bad alternators?

Thanks in advance, Jon