I'm working on building an electric motorcycle, but am somewhat confused / need tips.

1st, What do I do for gearing / transmission? Is the only way I can do it is just a chain to the motor w/o a trans?

2nd, Where can I get the batteries? I've been looking at the ones someone else posted earlier:
http://www.ragebattery.com/power-sonic/UB12550.html

do these seem like a good selection?

3rd, is there a controller that can sense speed and goes from amps to volts as speed increases?

4th, how do I tell how much a battery can take? I don't want one blowing up with me sitting on it


I'm also not sure about how I'm going to weather proof this thing. Or charge it

looks like you need to research a bit before hitting this project (no i'm not trying to belittle you at all) but honestly look at the other motor cycle posts and see what it is that they did. as far as seeing what components go together and all. you CAN use a transmission but most dont since its cheaper and easier to not do so.

As far as the batteries research what motor you want to use and find out a good balance between power, range, and weight, then go from there...

I understand, the thing is what I need depended a lot on whether I could use a transmission or not. I can't think of any easy transmission solution.

I guess this means I'll have to use a higher voltage motor and more smaller batteries than I planned.

What about a battery pack with a parallel to series switch


hmmm....

(goes off to do more research)

the english have 2 speed gearboxes on their grasstrack bikes. this may be a good option. pretty easy to regear as needed as well.

sounds like it could work. and if you set up the handle to be a variable power switch instead of just an on and off button you should be set

what makes you think you'll need a transmission? Electric motors have very wide power bands, and max torque at 0rpm. If you chose a gear ratio correctly, you shouldn't have to do anything for a motorcycle.

You could also use a CVT from Comet, under 300 bucks, but again, why? You can get a new front and rear sprocket made and a new chain for that. Plus less maintenance, less moving parts, less to go wrong.

http://www.geocities.com/CapeCanaver...79/evcalc.html

That should help you chose a ratio. Once you have the drag coeff (i set mine around 0.3. Then put the battery type, number and voltage, motor type, controller specs etc. Then you can change the gear ratio to get max speed and max range.

Too bad we can't do something like Pspice where it varies several different variables and calculates the max efficient design.

Good luck
Check my blog,
http://blog.evfr.net