I skipped the battery and went with a cap, it won't run your blinkers though.
A 1.2A SLA alarm battery will fit in the same area as the cap. I like those batteries because they are sealed and cost about $18.00, I've used one on an XR650R for a few years. You can see the location of the Reg/rect, it's a Rickey stator model, fits that location like it's made for it.
