See also:

Close the windows and glass sunroof
Driving with the glass sunroof and windows open results in increased air resistance and raises fuel consumption. ...

After the ignition is switched off
The roof can still be operated for approx. 1 minute, as long as no door has been opened. ...

Maintenance
The battery is maintenance-free, i.e., the electrolyte will last for the life of the battery. Your service center will be glad to advise you on questions regarding the battery. ...