In my 04, BD I had some type of sponge type material on the sides of the battery compartment to stabilize the battery. The downside is that the sponge gets old and compresses and the battery becomes loose and rattles around. I lost power that way when riding when a ring connector broke.
I removed all the spongy crap and replaced the sponge with custom cut, sheet fiberglass material on all sides of the battery. Now that sucker doesn't budge. Do the battery shake test- grab the fucker and try the wiggle it- if it's loose, you need to stabilize it.
Glad to see your ass is back in the saddle. :up: