On the light side,
As a High School project I used an electric car starter fitted with a sprocket, a car battery and on/off switch and replaced the ICE on an old minibike.
(1970's)
It was good for around the block.

Wonder if I had the first EV bike :lol:

Efficient drivers do it better.
1003 miles a tank personal record. 74MPG calculated. HCH1 CVT