My first conversion was electrifying an old Trek mountain bike with a 24-inch wheel kit, controller, and battery off eBay. Worked well as a commuter for a couple seasons, but the already-failing headset was getting too sketchy to ride.
Recently my older son (9) has gotten interested in ATVing. Wanting it to be electric, and for him to be able to work on it, I offered to build one with him. We visited a local Tractor Supply to take measurements from a Coleman AT125-UT ( https://www.colemanpowersportsusa.com/AT125-UT) youth ATV they had in stock. The manager stopped over and told us this particular one had never run; we ended up buying it for half price and free delivery. The final cost was less than I would’ve spent on aliexpress for the front/rear suspension, steering, wheels, and a pile of aluminum extrusion to build a frame.
After diagnosing and bypassing a bad ignition switch, the 120cc engine started on first-crank. So he’s having fun with it for now while I spec-out and price-out an electric drivetrain upgrade.
So far, I’m looking at various combinations of motor and controller, and the ATV-conversion threads on here have been super helpful!
- The 120cc ICE engine is spec’d at 8Nm of torque, no power spec given
- The vehice’s dry weight with ICE engine is 126kg. Kiddos are in the 18-25kg range now, but mom and I would like to take it for a spin now and then too.
- Looking at various BLDC motors in the 2-5kW power range with torque ratings from 7-10Nm
- Looking at VESC controllers and some of the other kits mentioned here: QS, Golden motor, Aliexpress unbranded…
- Trying to figure out how to mate up with the existing driveline - it’s an integrated motor/gearbox, so I’m thinking a gear motor (like QS 3kW with integral gear reduction) would be easiest to direct-drive, or fall back to a similar-sized BLDC with an off-the-shelf jack shaft.
I’ll post some more before pics/details here soon, and once I (/we?) choose and source some parts, I’ll post tons of build detail… looking forward to diving in!