Geekybiker,

You're right, the general method used to determine efficiency is to calculate WH/M, which will vary depending on terrain and riding patterns as well as the e-bike's motor and controller. Clearly the Watt Hours available varies by the size of the battery (I believe you calculate WH by multiplying V x AH). To calculate WH/M, you need to ride to a safe DOD to determine the number of miles you can get in any particular terrain (clearly, weather, especially wind, can have an affect, too). My battery pack is still in break-mode so I've not taken it down to safe DOD levels yet to calculate my WH/M. I've got to order a Turnigy watt meter/power analyzer for my handlebars. However, given the levels of power consumption I've seen in my rides to date, I would guesstimate that Ill be able to ride 27 miles and still be at a safe DOD (yes, that's with pedaling--I always pedal). Using that figure to plug in to the calculation, I get 17.7 as WH/M (V x AH ÷ M).