A bit more info on the 20wh/mile number that I totally made up.
The bike you linked has a 250w motor. Running it at 100% for an hour, if you were able to average 12.5mph for that time, that gives you 20wh/mile.
Based on the watt-hours we calculated earlier, and the manufacturer's claim of 30 miles, we have to assume they're figuring 25mph at 250w of power. This is technically possible according to (http://www.analyticcycling.com/ForcesSpeed_Page.html) but clearly we're in "best case scenario" land.
The bike you linked has a 250w motor. Running it at 100% for an hour, if you were able to average 12.5mph for that time, that gives you 20wh/mile.
Based on the watt-hours we calculated earlier, and the manufacturer's claim of 30 miles, we have to assume they're figuring 25mph at 250w of power. This is technically possible according to (http://www.analyticcycling.com/ForcesSpeed_Page.html) but clearly we're in "best case scenario" land.