I had the same issue three weeks ago, my 09" SG's battery crapped the bed as well. Is always on a trickle charge as well is the wifes Nightster. Went to the dealer the next morning w/the dead battery, they told me 4-5 hrs of charge and I said I might as well just buy a new battery and the service mgr said "just a minute, here take this new battery w/you" and stop by w/your bike so I can check the charging system. I did, and everything checked out A-OK. Well, my point is this, I think there is an issue w/some of these newer batteries and also "hats off to Cycle Connections" of Joplin, MO.
NYTSTR