I think you have a typo there. What's the difference between a) and b)? I'm a bit confused.I'm getting ready to build a light weight trike and need some good advice on what's already going to be an unconvential project. I've got 2 deep cycle 12v Optimas coming. I plan to use them in parallel with a pedal powered generator that will generate more than 48V pretty easily. Yes, I know It's definately outside the box, but I'm going for it. Ideally, I hope to set it up so that the generator charges the batteries and any excess voltage is automatically dumped to the brushed Etek style motor I'm using. Would it be possible to have battery A only engage when charging voltage is reached and battery B only engage when charging voltage is reached for it? Can I do this without a charging system? Am I just dreaming? I know that a slider throttle could do part of this but, I'm hoping to make it all work together seemlessly. Any advice would be grealy appreciated.
Trying to answer the underlying question anyway, you would have to have the generator set up in series with the charger and the motor, so that voltage from the charger would be split between the two. Certainly an odd configuration, and someone who knows more about electronics would have to advise as to how that can be done safely/effectively, as I believe the generator could end up creating a load on the motor instead of vice versa.
I'm a bit confused on the usage this would have though. If you're pedaling strong/fast enough to create more energy than a 48v motor is using, why have the motor and the batteries and charger and generator? It seems like you just made a really inefficient way to turn pedal power into electrical movement, instead of just using it to push the trike.