See also:

Parking the vehicle for a long period
If you leave the vehicle parked for longer than four weeks, the battery may be damaged by exhaustive discharge. - Connect a trickle charger. You can obtain information about trickle charg ...

General notes
If you cannot lock or unlock the vehicle with the SmartKey, either the battery in the SmartKey is discharged, the SmartKey is faulty or the starter battery is discharged. Check the battery in ...

Safety
The R-Class received a Good overall score — the highest rating possible — in the Insurance Institute for Highway Safety's frontal-offset and side-impact crash tests. It hadn't yet undergone IIHS' ...