Choosing the right controller for lightweight electric motorcycles and pit bikes
On electric motorcycles, from pit bikes to Sur-Ron models, the controller dictates almost everything: acceleration power, top speed, throttle responsiveness, and motor braking. It's also the component that's most often replaced when riders want to improve performance. This guide explains how to choose the right controller and what to check before making a purchase.
The essentials
- The controller must be able to handle the battery's full charge voltage, with some margin to spare.
- The phase current determines the torque; the battery current determines what is being demanded from the battery.
- It must be able to read the motor sensors and, ideally, control the motor using vector control.
- More controller power without more battery capacity will result in power cuts; more controller power without reviewing the brakes is a safety hazard.
What the controller does
The controller takes the direct current from the battery and converts it into alternating currents that drive the motor. At every moment, it decides how much current to send, based on the throttle, speed, and safety features. Our controller guide explains this in detail: the principle is the same for an electric scooter and a lightweight motorcycle.
Selection Criteria
The voltage
The controller must support the full battery voltage, not just its advertised voltage, with a margin to accommodate voltage spikes during motor braking. See our guide on upgrading to a higher voltage, which also applies to motorcycles.
The currents
Two settings are often confused. The phase current flows through the motor and determines the torque, which is the force at startup. The battery current is the current drawn from the battery and determines the power. A controller advertised with a very high current rating is useless if the battery cannot supply it.
Motor control
Un contrôleur en commande vectorielle (FOC) donne un moteur plus doux, plus silencieux et plus efficace qu'une commande simple. Voir notre guide sur la commande vectorielle. Sur un moteur à aimants intérieurs, un contrôleur compatible peut aussi exploiter le couple de réluctance : c'est le réglage MTPA, expliqué dans notre guide sur les moteurs IPM.
The sensors
The controller must be able to read the motor position sensors, Hall sensors, or encoder. See our guide on motor position sensors.
Tuning and communication
A good controller can be configured: driving modes, throttle response, motor braking, and temperature limits. It also communicates with the battery and the display, often via a CAN bus.
The RM30 motor for Sur-Ron
Our RM30 motor for Sur-Ron Light Bee is an interior permanent magnet (IPM) motor, which allows for MTPA (Maximum Torque Per Ampere) activation on compatible controllers. It is equipped with Hall sensors, allowing it to work with most controllers, and is resistant to heat up to 180°C. It comes with a pulley for the original belt.
And what about the Rage controller?
Our controllers for light motorcycles come with RageLink, our new ecosystem. You can sign up for the waiting list from the RageLink page. For manufacturers or custom projects, our design office is already working with two-wheeled vehicle manufacturers.
Workshop tip
More torque at the rear wheel means more stress on the drivetrain and more energy that needs to be dissipated during braking. Check the belt or chain, and review the brakes before increasing the power.
Frequently Asked Questions
Can I keep my original battery if I upgrade to a more powerful controller?
Only if the battery and its BMS (Battery Management System) can handle the requested current. Otherwise, the BMS will cut power during acceleration: see our guide on batteries that cut out during acceleration.
Does the RM30 motor work with my controller?
It is equipped with Hall sensors, making it compatible with most controllers. To take advantage of the MTPA (Maximum Torque Per Ampere) feature, you need a controller that supports it.
Can a modified electric motorcycle be driven on public roads?
A motorcycle that is approved for road use and then undergoes power modifications is no longer compliant with its original approval. Modified machines are intended for use on closed circuits and private land.
Should the controller be cooled?
Yes, it generates heat with each acceleration. It must be mounted on a surface that allows for heat dissipation, or be ventilated, and should be protected from water and splashes.