Electric motorcycle project
This project is about designing and building an electric motorcycle from scratch, and sharing the knowledge gained along the way. The focus is the complete drivetrain: a three-phase permanent magnet synchronous motor, the power electronics that drive it, and the battery that powers it all.
Follow the work in the build log, or dig into the documentation to see how each subsystem is designed.
The central component is a brushless permanent magnet synchronous motor (PMSM) in an 8-pole, 48-slot configuration. The rotor is 108 mm wide and 100 mm in diameter, fitted with neodymium magnets. The housing is aluminium with cooling fins, and the magnetic core is built from 29-gauge electrical steel laminations.
Inverter
Section titled “Inverter”
The inverter is the brain of the system. It converts the battery’s direct current into sinusoidal alternating current in the motor windings, controlling amplitude, frequency and phase relative to the rotor position so that the stator’s rotating magnetic field interacts with the rotor’s permanent magnets.
Battery
Section titled “Battery”
Energy is stored in 96 lithium iron phosphate (LiFePO₄) cells in the 33140 form factor (33 mm diameter, 140 mm height). The pack is wired 48s4p — 48 in series, 4 in parallel — for 154 V nominal. Each cell can discharge 75 A, giving a maximum pack output of 300 A.
Junction box
Section titled “Junction box”
The junction box sits between the battery and the inverter and houses the protective components: the main contactor, the fuse and the pre-charge resistor.
The chassis is a welded steel-tube trellis frame, chosen for its simplicity to build and its cost-effectiveness in small-scale manufacturing.