Powdersummit
10 mW
I've been lurking on this forum for probably close to six months on and off to learn as much as I can about building an electric bike and as much technical stuff as I can. I guess now is as good of time as any to dive into the insanity. With that said here is my idea.
The type of riding that I do is largely varied. There are times that I would like to hit 30+ mph going down the road but at the same time I would also like to have something that can crawl up a goat path (yes I know slippage issues are a problem on a friction drive but I have ideas for that so ignore that for now). That makes gearing a problem to have such different needs of high speed cruising and low speed crawling. My solution is to have a two motor setup where only one motor is running at a time but each of the motors have different gearing to the drive spindle. For your high speed motor you could have a 2:1 gear reduction to the drive wheel. If you used a 300kV motor at 44V on a 2:1 ratio to a 2 inch drive spindle you could get upwards of 30mph (these are rough calculations). Now if you wanted a low range you could have a second motor of the same size that has a 3:1 reduction to the first motor (using the first motor as a jackshaft) for a total of 6:1 reduction and a max speed of 10mph. This would give you more control at low speeds plus having 3 times the torque or less amp draw from the batteries. This system would have to incorporate one or two overrunning clutches to keep the second motor (low range) from trying to spin a 30k rpm while in high range. I hope this makes some sense.
As for the electronics part a person could use 1 speed controller and switch the phase wires back and forth between high and low range motors or you could use 2 speed controllers and just switch which controller/motor receives the throttle. I hope this makes sense to some of you out there, it's late and I've spent the better part of my day chasing after my 2 year old son and constantly thinking this idea through.
Carl
The type of riding that I do is largely varied. There are times that I would like to hit 30+ mph going down the road but at the same time I would also like to have something that can crawl up a goat path (yes I know slippage issues are a problem on a friction drive but I have ideas for that so ignore that for now). That makes gearing a problem to have such different needs of high speed cruising and low speed crawling. My solution is to have a two motor setup where only one motor is running at a time but each of the motors have different gearing to the drive spindle. For your high speed motor you could have a 2:1 gear reduction to the drive wheel. If you used a 300kV motor at 44V on a 2:1 ratio to a 2 inch drive spindle you could get upwards of 30mph (these are rough calculations). Now if you wanted a low range you could have a second motor of the same size that has a 3:1 reduction to the first motor (using the first motor as a jackshaft) for a total of 6:1 reduction and a max speed of 10mph. This would give you more control at low speeds plus having 3 times the torque or less amp draw from the batteries. This system would have to incorporate one or two overrunning clutches to keep the second motor (low range) from trying to spin a 30k rpm while in high range. I hope this makes some sense.
As for the electronics part a person could use 1 speed controller and switch the phase wires back and forth between high and low range motors or you could use 2 speed controllers and just switch which controller/motor receives the throttle. I hope this makes sense to some of you out there, it's late and I've spent the better part of my day chasing after my 2 year old son and constantly thinking this idea through.
Carl
