If I am going away for 10 days to I need to put a trickle charger on my 528 ?

You can but honestly I don't think you need to unless you have already been having battery issues.

Oh make sure any aftermarket items are turned off or unplugged. Phone chargers, gps, ect.

I agree. Not for 10 days. One time when I flew to see my son I left my car in long term parking for 15 days and it fired right up. This was not my truck, a Toyota I had at the time. But correct me if I am wrong here..the battery is in the trunk on that car? If you do decide to put the trickle on pull light bulb out and do NOT disconnect battery.....that applies whether you put the trickle on or not

All good advice. If your car has parasitic drain, you should put on the trickle charger. BMW's have a lot of sensors and if the car doesn't go to sleep properly or something is still drawing power, you might not be able to start it when you get back. It also depends on the weather. If it's really cold out while you are away, your battery could freeze and a trickle charger will help prevent that.