Accessory option?

[gnpower]

With previous vehicles I used to move the key in the ignition towards the driver to get it in the accessory mode so that all the electronics would be on without starting the engine. Is there such a mode in the 1er?

I know all or most of the electronics in the car turns on when you place the key in, but it shuts off after about 15-20 minutes.

The reason for this is that I would like to go to a drive-in movie theatre and don't want to take the key in and out every so often. Do you think that battery would last in this mode (if it exists) for a good 4 hours? Would the car start?