What is a Motor Controller / Inverter?
Converts the battery's stored DC energy into the form the motor actually needs, and manages how much power it gets.
Simplified animation — not to scale.
In plain English
The controller sits between battery and motor, converting stored direct current into the precisely timed pulses the motor needs, while also deciding exactly how much power to deliver based on throttle input.
“The electric bike's equivalent of a carburettor and ignition system combined — metering exactly how much 'fuel' (electricity) reaches the motor and when.”
How it works
Reading the throttle position many times a second, the controller switches battery current on and off at high frequency to create a rotating field in the motor, precisely matching torque output to rider demand. It also manages regenerative braking, feeding energy back to the battery when the rider closes the throttle or brakes.
Signs of trouble
- ⚠Jerky or inconsistent power delivery
- ⚠Overheating and reduced power under sustained load
- ⚠Warning light relating to the controller
- ⚠Complete loss of drive with no other symptoms
£300–£1,200
Always get a written quote. Prices vary by bike, region, and parts brand.