Could you please provide the last 7 digits of the VIN of the vehicle?
Also, please elaborate on the issue, does the remote work at all; to lock or unlock the vehicle?
It is likely the battery in the key is not holding a charge; not that the vehicle is not recharging it. It is common for those remote key batteries to last 6-7 years before they begin to fail. The battery in the remote is not a replaceable component either. You will have to buy a new remote from your local bmw dealership. They retail for about $200. You will need to provide your license and vehicle registration for them to photocopy for proof of ownership of the vehicle.
They will then have to initialize the new remote to your vehicle, they should provide this service with the purchase of the new remote. This is simply performed by entering and closing the drivers door; cycling the key to the "key on" position, but not starting the vehicle; removing the key from the ignition; then pressing and holding the lock button and tapping the unlock button three times in succession. Then the new remote should work with the vehicle.
Hope this helps, please use the accept button as this is the only way I receive credit for my work.
Wish I had better news,