I hooked the bike to an optimate3 and the V has gone up like a rocket. Now reads 13.7V running with the lights on and 14V off and 12.5V with the engine off. Even when I changed the battery (only 1 month ago), I've never seen any higher of 13.4 in a good day, normally 13.3. I went for a ride today and the bike managed to keep the voltage so I will try to hook it to the optimate 2 days a week and see whether it's enough. I use the bike everyday so I will have to monitor the V and hook it when necessary. If this fails, bye bye Datatool!