[raggnerredbeard]

I have a 2004 636 and two weekends ago I had "The Itch" and got my bike out for the first time this year. I left the battery disconnected all winter and it started just fine when I hooked it up. I rode for just a few miles before my fingers froze and when I was done I disconnected the battery again. But today I was going to go for a long ride and when I went to start it, all the dials came on like normal, but when I pressed the button there was just a click and all the power shut off. After that, the dials wouldn't even come on. So I jumped it just like I've done times before and it started like normal, but when I took one of the cables off the battery, the bike just completely turned off. WTF? I just bought that battery last spring.
Any thoughts?

 

[MFolks]

I suspect the battery needs replacing. A battery tender would have saved you the cost of a new battery. It's designed to charge the battery at a low current(1.25 amps or so) and then switch to a maintain charge condition.

Motorcycle batteries will self discharge if not kept on a charger. Sulphation will set in leading to the plates to form a coating that ruins a battery.

I'd avoid using a car rated charger as they can quickly ruin a battery if it's left on for a while(like over night). Some people have said it's o.k. to charge at 2 amps, myself I'd rather not.