Got in my car this morning, and I had an eery feeling as if something was different, no lights, window didnt slide down 1", no radio, no start-up. I thought no, so i checked the voltage at the jump-starting posts under the hood, Nada Volts...
I called BMW Road side assistance, except this time it was Home side assistance
as i was parked inside my heated garage. The guy came within 30mn, plugged his battery pack and the car started right away. No accessories plugged in, no aftermarket modifs whatsoever, no coding, ... no lights in the dash, no warning, just like that. I drove it the last two days normal.
Its at the dealer now, they are charging it slowly and unfortunately has to sleep the weekend there (dealers close on weekends here). The tech confirmed that it was low capacity but they need to keep it under the charge for at least a day to do further tests. The trick of driving for 20-30mn HWY speeds does not fully charge those batteries, but unsure if I take his word for it.
A fluke of hazard, weak or dead battery ?
UPDATE: No trouble found, Mysterious gremlins drained the battery.