Watt Watchers


Well-Known Member
Part of the fun of riding an e bike, for me at least, is tracking my wh/mi usage. Although I have a pretty good idea of where I am at in regards to this I still get a kick out of setting my cruise control at different speeds while riding in different situations to see how low I can go, or how high. Having a readout that calculates it for me on the fly is nice but with some simple math anyone can play. There is an explanation of this here: https://www.electricbike.com/watt-hours/

For the most part companies calculate their range numbers based on the format of V of system x AH of battery = Wh available. But in reality there are too many factors while riding to say that you can get X amount of miles out of a single charge. Knowing what your average wh is specific to terrain and how much you add via pedaling rarely is what manufacturers suggest.

It seems like 20wh/mi is about the standard for a rider that includes pedaling along with the motor assist in reasonable conditions so that is a good place to start. Efficiency of the system also plays here as there is variance in regards how a mid drive, geared hub, direct drive hub, PAS or throttle and effective gear ratios can affect your number but it is your system of choice so knowing in advance what you average is key to doing a ride without running out of battery.

Yesterday I set my cc at 20 mph for my flat country 2 lane minimal traffic light headwind paved road ride to where I wanted to get to do some exploring and this was the result with some active pedaling pressure the whole way

What this tells me is that given those optimal conditions with my 52v 11ah = 572 wh battery I should be able to do 65 miles per charge (572 divided by 8.8). Knowing this is one thing but I doubt I will ever actually do this unless I set out to do it for that distance. Also as voltage drops the system becomes less efficient and raises the wh/mi figure.

In general I calc my rides in the 15-20 wh/mi range as over the last 1000 miles using my preferred system it has proven to be so time after time. So when I set out now I can be reasonably sure that I will return without having a dead battery a few miles from home and can relax and enjoy the ride!

As they say YMMV.