Oh you want to have both an electrical system and a mechanical chain-drive, i thought you wanted maximum design simplicity, that's why i left out the chain-drive. You know that you can peddle a generator to power a wheel-motor, you'll have some conversion losses but since you are substituting with battery power anyway that doesn't really matter.
>That would be fine for cruising on bare, dry asphalt, but on uneven terrain (think packed ice with patches of snow) I wonder how responsive such a thing would be.
Yeah an electrical-only system is rather elastic in it's responses, if you want to suddenly launch into an explosive sprint to the finish line in a cycling competition, this is no good, but in difficult terrain, this could be advantageous because you'll have smooth continuous power-delivery that helps with traction.
>Would the throttle be on the handles the way that a motorcycle's is?
No there's no throttle in this, you have a switch with multiple positions that represent different parallel and serial motor coil configs that change speed for a given voltage of the motor. You'll choose a switch position that basically represents a given speed, and then your e-bike will accelerate (limited only by the internal resistance of the battery) until it reaches the set speed. You'll realistically have between 3 to 6 speeds. If you don't want to accelerate you turn it off. This is functional but you sacrifice fine speed control for maximum design simplicity. You also have to choose an appropriate battery that won't burn out the motor.
>I would hate to have to use one of those expensive lithium batteries. It just doesn't seem very Soviet. Something dirt cheap that you can recharge with a crank and some water–that's Soviet as hell.
You don't need that many batteries for an e-bicycle, so it's not as cost-prohibitive as with cars to use lithium cells, but yeah a less resource constraint battery chemistry that's also light-weight enough, that's still missing.
>That wouldn't work with an alternator.
Yeah that's the case for all metal-air batteries, but they do store huge amounts of energy and are super cheap. You can have 200km or 125miles range per battery (aluminum-air version) and could gPost too long. Click here to view the full text.