Hi...wow! more good stuff to think about. So...if I understand what you folks are saying:
1. If I want to make my ebike go faster I can change the batteries (probably controller, etc also) to a higher amperage battery and it will make it a higher wattage motor, which will make it go faster. (Hopefully the motor was designed for this or it will burn out quickly)
2. If I start with motor A and increase the amperage there is a limit to the amperage/volt combo that motor A can handle without affecting it's life. At some point I should change to motor B which will have more windings, etc so that it can handle either more volts or more amps - or both.
3. The ability of a bike to accelerate quickly is related to how much torque it can generate. If I want higher torque to available at a broader range of speeds I need to use gearing.
4. More weight is going to require more watts (either more volts or amps) to achieve the same speed than the same bike with less weight? My guess is that because more weight, an additional rider or packs, will also increase wind resistance a bit that this relationship is not completely linear.
5. From other readings and postings...it seems that right now 36 volt batteries are more commonly available (could also mean cheaper) than 48v? I know that many bike's batteries are built up of 12 volt cells but I have read that lithium and newer technologies come in fixed arrangements, i.e. 12 volt, 18 volt, 36 volt, etc.
6. It was mentioned that higher voltage motors use thinner wires. Does this mean that they are lighter, i.e. power to weight ratio?
So....for example...if I am happy toodling around on my ebike with a 240w/36 volt motor and its speed but want to extend the range I can add another battery or two. If I want to make it go faster I can change the electrical system so that the batteries/controller, etc provide more amperage to the same motor. If I usually need to take a passenger or haul other goods and my bike does not provide satisfactory performance after maxing the amperage I need to upgrade the motor.
Which is lighter - given two systems with equal wattage, one has higher voltage, the second has higher amperage? which will have more range?
Am I close?
Last edited by pengyou; 10-24-07 at 12:37 AM.