My average day trip is 500 miles, and the batteries lasted for a 600 mi. day. I probably should have been clearer. I verified 8.5 hours, and have yet to verify how long it lasts beyond 8.5 hrs. My guess is the 600 mi. day took 10 hrs of riding.
Do you ever use the controls on the MW600 while you're riding? Or just tuck it in an internal pocket?