I really must disagree with this. I have a 14 mile commute. Neither end is particularly higher in elevation, but there are lots of hills in between (as a reference, I got up to 38mph on a downhill). I have one battery, and recharge it at work for the return trip. I pedal the whole time (well, not on big downhills, but other than that) and only use the motor on uphills. If the hill isn't too steep, I will use the motor (with me pedaling) for about 20 seconds to increase my speed, then just pedal, then use the motor again, etc. If the hill is steep, though, I just use the motor on constant, with me pedaling in high gear to help it. Admittedly, I only weight 125, but my husband is about 170 and he has done the same commute with the same results - the first time, he didn't pedal much and the battery got drained, but then once I told him he had to do some work, it's been fine.

I guess if people are using the motor on flats, then they won't get the range I do. I only use it when I can't keep it above about 13mph just with pedaling (which basically means, on the up-hills).

Also, I posted this before, but make sure you are leaving you battery charging for a good 6 hours, even if they light turns green after 3 hours (mine does this, but when I unplug it when the light turns green, the battery won't make it the whole 14 miles.)

Cathy