This bicycle add-on uses an electric motor to help you out. This way the motor takes advantage of the gearing normally available to the cyclist. What interests us most about the system is the DIY battery work they're doing. The cells are using Lithium Iron Phosphate technology. The li-ion cells you're used to seeing in consumer electronics are actually Lithium Cobalt Oxide. The Iron Phosphate flavor offers longer overall lifespan, better operation between charges over that life, and improved cold-weather performance. The drawbacks include a 20-cycle break-in period and an affinity for trickle-charging versus faster charging methods.
The 48V cell seen above will provide 30-40 miles of travel between charges. We feel that getting the power plant out of our vehicles is an important step toward energy overhaul but it can only happen if the battery technology makes it possible. Then again, perhaps we're barking up the wrong tree and should have placed our bets on compressed air.