Either alternator or voltage regulator is what i've narrowed it down to.
I live in a small town, the local shop that i would trust with it is booked for two more weeks so it's going to a City close by with a Euro specialist.

BmW quoted me my jobber price of $1100 ouch just for the alternator. liquid cooled bugger

I have found an aftermarket version for $500 my cost that eases the pain a bit and its 2.3hrs flat rate. So i'm banking on $900-1000 by the time it's done.

Now just have to see if between the new battery and the old one which does hold a charge, if i can drive it 75km to the shop and avoid the flatbed .

4 months with the BMW
stranded it in the driveway twice with a dead battery
3 weeks in the body shop
now another week for alternator (died before a long weekend)

4 years and my Hummer never failed me once! What am I doing?