BMW R1200RT/R1250RT Forum

The Haynes Manual (R1200 D.O.H.C. Twins 2010-2012) specifically states "Do not connect a battery charger to the battery terminals while the battery is on the Bike". As I have always carried out this very procedure (Three R1200RTs) without any known problems I am wondering just what negative results "could" have occurred. I carry out charging using an Optimate Charger coupled direct to the Battery Terminals via an additional Aux. Socket.

I think the danger is that, some de-sulphating battery chargers can deliver up to ~18 volts which may damage the voltage sensitive electronics on the motorcycle.

The alternator onboard charging system is voltage regulated to a max. of ~14.5 volts.

Thanks David,
No worries then.