No batteries required: DIY electric-bike runs on solar power (videos)
An electric bicycle powered by solar panels that are on the bike rather than by a battery. Now that's something I haven't seen before! This is more a "cool project, but not quite practical yet" rather than "this will be mass-market soon", but that's ok. We always learn more by trying things that seem a bit crazy at first!
Terry Hope is the DIYer behind this project, which he calls the Solar-Cross ebike. Here it is in action:
This solar EV is built upon an 1998 Specialized FSR mountain bike which cost me $200 with an additional $500 to convert to solar electric.
Efficiency and portability are key features to my ebike design, like the custom freewheel crank that consists of one sprocket and two chainrings. On the outside is a 80T - 0.25" chain sprocket which the electric motor drives, inside this sprocket is a 42T mtb chainring and behind this is 22T chainring. The 22T chainring can reach a speed of 22km/h while the 42T chainring can achieve 40km/h and +50km/h is possible with the rider pedaling along with the motor.
Here's the Solar-Cross up close and from all angles.
The practical version of this would be putting the solar panels on your roof and charging the ebike's battery with them, but that wouldn't be nearly as much fun as figuring out how to put the panels directly on the bike!
See also: 5 interesting facts about electric-bikes