On 9/25/2017 1:07 PM, sms wrote:
...

The electric wheels all have drawbacks. Having a large battery spinning
inide a wheel, or even stationary inside a wheel just seems like the
wrong approach. At least the Copenhagen wheel has regenerative braking
so the batter size can be a little smaller, but most e-Bikes don't have
this.

Back when I was doing a cost comparison of gas vs electric e-bike
setups, the example I used for e-bikes was the BionX system, because
they were the only company that would actually publish real numbers for
range and battery recharge life-cycle estimates.

And at the time I think it was the only one that had regenerative
braking, and users on endless-sphere forums reported that using the
feature really didn't add much range unless you were literally riding
down a mountain. At best it would add maybe 5% under typical riding
conditions.

If all it takes to implement is a few more tiny electrical parts then
including it is no big weight penalty, but (as of maybe 5 years ago)
there didn't seem to be any great advantage to it in the case of e-bikes.