Converting a 125cc Motorcycle to Electric: Drive System Checklist

Fuel-to-electric conversion is one of the fastest-growing projects among workshops and small OEMs. Here is the drive-system checklist we walk customers through.

1. Define the target. Top speed, range, rider + payload weight and terrain. These set motor power, battery capacity and gearing.

2. Motor. Mid-drive (chain/belt to the rear wheel) keeps the original swingarm; hub motors simplify mechanics but add unsprung weight.

3. Controller. Match peak phase current to the motor and peak bus current to the battery (see our sizing guide). A typical 125cc-class conversion (about 8–9 kW, 120–150 A bus current, ≤350–450 A phase current) fits T-400 or T-500.

4. Or a 3-in-1 drive unit. Vector's 3-in-1 unit integrates motor, controller and reducer in one IP67 housing (5, 10 and 30 kW classes), reducing wiring and mounting work. See the 3-in-1 drive unit.

5. Battery and BMS. Voltage platform (commonly 72 V), discharge current ≥ controller bus current, and pre-charge enabled.

6. Wiring and safety. Main battery switch, fuse, correctly sized B+/B− cables, a common signal ground at the controller (never directly to battery negative), and a 120 Ω CAN terminator at each end of the bus.

7. Controls. Throttle, brake cut-off, kickstand cut-off, reverse, regen braking and a CAN dashboard. T-Series supports all of these.

8. Tuning and testing. Run motor parameter learning, set current limits within battery capability, then test on a stand before road use.

Planning a conversion program? Tell us about the vehicle.