Hello! In planning stages of 50cc Moped conversion

Hi everybody,

I have a 50cc Tomos Bullet moped, that while having a solid frame, wheels, tires, etc, has no electronics on it, and a seized top end. The costs to get it running again are so high that I decided I had 2 options, mutilate another moped (and I’d have to find one first!) or go electric. I’ve decided to go electric.

If you would be so kind, I need a little bit of help. The stock engine was 50cc, generating about 1.5 HP and a top speed of about 27 MPH. I’d like to use it for some local runs, basically I’d like comparable performance with about a 30-40 mile range. I would only truely use it for MAYBE 20 miles, as school, the grocery store, several friends, and the library are only 2-3 miles away each direction, and I do have some mild-medium hills here.

I believe that I worked out the 1500watts is about 2HP sustained. Am I correct? is 1500 watts too big? I can find a 1200watt/36V motor for about $100, but I’m having a hard time finding a 1500 watt motor.

I’m thinking off running 3 12V batteries, likely 2 as “saddlebags” and one under the frame near the motor. I plan on mounting the motor where the engine was, and using the same drive chain configuration. I would entertain the idea of 24V, but I don’t think I’d get quite the range I want. I am also considering building a battery trailer for longer distance, if needed.

I’ve looked at this controller:


and it seems simple enough, and potentially what I want, but I don’t know what the 100amps work out to (what does that even refer to? it’s own output?) and if it’ll be enough to drive the 1500watt motor. It has a matching throttle for handlebars that is exactly what I want.

Thanks for any help!