[BMW_Addiction]

Your battery is probably weak. The electronics are very sensitive. If mine sits over 24hrs, I attach the battery tender....

 

[Dexter Morgan]

Your battery is probably weak. The electronics are very sensitive. If mine sits over 24hrs, I attach the battery tender....

Mine has sat for 3 weeks + in the dead of winter in a garage with no problems whatsoever.

 

[frieseke]

That's a feature of the e60. Mom and dad have a 550i and the stupid thing always drains the battery dead after sitting for a day or two. BMW tried replacing the battery with a gel battery and updated the programming on it, but the thing always dies on them. BMW suggested always locking the car even when parked in the garage, but it will still die. Luckily for mom and dad the lease is up on the car in June so they will be getting a new f10 550i and they will let someone else have the hassle of messing with the electrical systems on the car.

I believe it might have something to do with comfort access. On the older 08 and back models I think there is a drain on the system when the key is close enough that the car can almost sense it. I park my car in the far end of the garage and leave my keys in the middle of the house and I've never had any problems with the battery draining on my M5. I've left it parked at the airport for a week when evidently we had a wicked cold streak of -40 weather and when I got back the machine started up without any problem.

When mom and dad notice the systems starting to reset themselves, they always throw a trickle charger on it in the off chance their car might go dead.

 

[Clyde]

This is odd. today I started my car and noticed that it was asking me for the time (it had the date though), and my mileage/fuel consumption, etc had reset. My radio presets were OK, however.

Has anyone had this happen to them?

On my car, comfort access will be disabled and the clock will reset when the battery is weak.
A Battery Tender solves the problem for me.