An e-bike controller is the electronic heart of an e-bike. It controls and coordinates communication between the motor, battery, display, and sensors (e.g., pedal force sensor, speed sensor). Without it, the interaction of these components would not function.

Tasks of an e-bike controller:

1. Engine control:
   The controller regulates how much power is transferred from the battery to the motor – depending on your pedaling power, speed and selected support mode.

2. Sensor evaluation:
   It processes the signals from pedal force, torque or speed sensors and decides how much support the motor should provide.

3. Energy flow management:
   It ensures that the battery is used efficiently and prevents overload, overheating or deep discharge.

4. Communication with the display:
   The controller transmits information such as speed, battery level, support level or error codes to the display.

5. Security features:
   In case of malfunctions (e.g. defective sensor, overcurrent, overheating), the controller switches off the motor partially or completely to prevent damage.

Where is the controller located?

Depending on the e-bike model, it can be located:

• in the motor housing (often in mid- and hub motors),

• in the battery case or

• in a separate control box on the frame.

Important NOTE

The controller is generally not universally interchangeable – it must be precisely matched to the motor, battery, and sensors. Therefore, in the event of a defect, a compatible replacement from the same manufacturer is often necessary (e.g., Bosch, Shimano, Bafang, DJI).

Conclusion

The e-bike controller is the "brain" of the e-bike — without it, there would be no controlled assistance. It ensures a safe, efficient, and smooth riding experience.