From what you've described, you definitely have a drain on the battery when it is on the bike. And since it drained the battery in 3 hours that one time, it's a pretty fair drain. And also since it seems to be holding the charge off the bike, I wouldn't fault the battery. Somewhere is a drain, you might double check the volt meter just to be on the safe side. Maybe take it out of the system for a few days, since it seems to be off a bit anyway.