German E-Rocket (bicycle/motorbike 50mph)

As far as I can gather it has got an electric motor + battery in it and still needs charging, its just that it has no throttle, the speed and energy input of the motor is proportional to your cadence so its really just a normal electric assisted bike.

hexactly. i rode an early one of these about 12 years ago. it also featured regenerative braking to top up the battery. very broadly speaking i would expect regenerative braking to extend efficiency/battery life by 20% or so?