Recently took a 28 mile ride on a rail trail with my Allant +7, no large hills. Average speed was between 15-20 mph, paced by a younger more athletic biker. I charged my battery prior to the ride and rode exclusively in the EMTB lite (old tour) selection. Range estimate at start was 122 miles, range estimate at finish was 151 miles! My battery strength did go down 1 bar from start. Don't suspect I'll need the battery extender!