As well as terrain and efficiency of the bike (and the viscosity of air that day), tyre pressure, what you ate for lunch, the drag coefficient of your haircut, size and shape of your nose, whether you have oily skin, whether your skin is wrinkled or smooth, if you've shaved your legs or are wearing tights (ask D.C.), or if like me you're as aerodynamic as a wardrobe riding a bike because you're fat etc. I believe it depends on the fitness of the rider - nealh cycles millions of miles a year and copes well with small batteries. I, on the other hand, require all available electric assistance at all times. 36V 322wh:
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...is 8.94ah. If all of that capacity was available, on my bike - it would last me less than 20 miles, but there's the 31% (ish) battery protection level to consider, so it'd give me personally, about 13 useful miles. Nealh could cycle thousands...