I have been monitoring mine with a battery problem. Currently, if mine sits for a week in the garage without use, the battery drains to about 12.10 volts which is not enough to start the car. After several pushes of the start button, some of the electrics seem to shut down to proiritise the starting function, and on about the 5th push, the car starts on its own. After running around at the weekend the battery charges to about 12.55 volts, at which the car starts no problem. But after a week this drops either due to power drain from the cars 'wake ups' or the battery is not retaining charge

http://www.xoutpost.com/x5-e70-forum/...est-avoid.html

Armed with my research I am now ready to go to the stealer and ask him what he's going to do about it. There has been a service bullitin advising dealers about a software fault that causes the car to 'wake' excessively, and is one of the main reasons for an excessive power drain.