BMW very kindly supply you with a Can Bus Supported Auxiliary Port on a range of their bikes that means you can easily wire your Sat Nav into the bike, meaning it will be powered from the battery of the motorcycle, however when you turn the bike off the Can Bus System then shuts down the power to the sat nav a short time later resulting no power going to the sat nav cradle and no battery drain.
Well that is the theory anyway, however some users have experienced battery drain and blame this set up, claiming that the Can Bus System isn’t compatible with their Sat Nav. That may be and BMW won’t say officially if that may be the case, stating only that their ‘Sat Nav’ port is for use solely with their Navigator System, and why not if you want to be 100% sure that everything is going to work beautifully together then you need to hand over £700 for the privilege.