Z3 battery drainning

I have a 2001 Z3 and was fine until last fall when a couple of times if I left it parked for a week or so,, it sounded like the battery was low and just started. After storing the guy who moves and starts the cars called to tell me the battery was dead. So this spring I put a new battery in but it still will drain down and not start if I don't start it for a week or so. Bottom line new battery same issue???? any suggestions????

You can start by pulling out the bulb in the trunk.
http://www.bimmerfest.com/forums/sho...d.php?t=339401
Otherwise the procedure is to put a meter on the battery to check amperage draw.
If the ammeter is reading over 25-50 milliamps, something is using too much battery power, start pulling fuses.
The fuse that reduces the drain is the circuit that is draining the battery.

Thanks for the info,,, the trunk light was the first thing I did and it made no difference. I will try your suggestion with meter and pulling fuses.

No, you pull the trunk light bulb as it will be a drain while you are in there looking for the real drain.

Well I finally found what was draining my battery! It turned out to be a after market rust protection system. Did not even know it was on the car funny thing is whoever did the initial instal did such a good job it looked factory and it was not until I had it in at the dealer that by chance somebody questioned the one wire. So we pulled the fuse on the unit and things are fine.