First i admit I an new to the forum and BMW motorbikes. I have just purchased a new 1250GS. Whenever I finish a ride I always like to put the battery on float charge. I have read in the Riders Manual page 195 Notice at the bottom of the page states the motorcycle on board electrics know when the battery is fully charged. The on board socket is switched off when fully charged. I measured using a dummy socket and the battery is 11.75 V but plugging in a oxford Optimiser 900 it shows 0 volts 0 amps . Is this a problem with the charger or at what voltage does to batter drop to require a charge. All help appreciated