VESC: A simple explanation of the open-source controller for electric racing machines

As soon as you become interested in electric racing scooters, electric skateboards, or DIY machines, one name keeps coming up: VESC. People talk about "switching to VESC," "tuning your VESC," and "VESC Tool." Almost all the documentation is in English and scattered across forums.

This guide explains, in French and without requiring any prior knowledge, what a VESC is, how it differs from a traditional controller, its limitations, and the steps involved in setting it up for the first time.

Where does the VESC come from?

VESC stands for "Vedder Electronic Speed Controller," named after its creator, Swedish engineer Benjamin Vedder. He launched it in the mid-2010s for electric skateboards, openly publishing the workings of his controller. The project has grown with a large community and has expanded to include scooters, bicycles, hydrofoil boards, robots, and go-karts.

The project comprises three elements:

• The firmware, which is the program that runs inside the controller, is released under the open-source GPL v3 license;
• VESC Tool, the free configuration software, is available on Windows, macOS, Linux, Android, and iOS;
• Hardware: These are the electronic control boards capable of running this firmware, manufactured by various brands.

VESC is a registered trademark. Consequently, you will also find controllers marketed as "based on VESC" or "compatible with VESC Tool": these use the same open-source firmware, but with hardware specific to each manufacturer.

What the VESC changes compared to a traditional controller:

The original controller in a commercially available scooter is a closed box: some settings are accessible through the display, but the rest is locked by the manufacturer. A VESC controller unlocks everything.

Vector control (FOC)

A VESC controller operates brushless motors using vector control, also known as FOC (Field-Oriented Control). The current varies continuously across the three phases of the motor, rather than switching between discrete levels. This results in a quieter motor, smoother acceleration, and more precise throttle control. Our controller guide explains this difference in more detail.

Motor detection

To properly control a motor, the controller needs to know its electrical characteristics: its resistance, its inductance, and the voltage it produces when rotating. With a VESC, you don't have to look for this information in a datasheet; the VESC Tool measures it. The motor first emits a whirring sound during the initial measurement, and then spins on its own for a few seconds during the second measurement. That's why we perform this "wheel-lift" detection.

The detection process also identifies the motor sensors (Hall sensors, encoder) when they are present. Without sensors, the VESC can deduce the motor's position based on the voltage it produces when the motor is rotating.

Current limits

A VESC (Vehicle ESC) defines several limits that must all be configured: the maximum current in the motor, the maximum current drawn from the battery, the braking current, and the current returned to the battery during braking. In addition to these, there are voltage thresholds (below which the battery is protected) and temperature thresholds (above which the power is reduced). These settings are what differentiate a fast and reliable machine from one that is prone to failure.

Data and diagnostics

The VESC Tool displays real-time data such as current, battery voltage, controller and motor temperatures, and keeps a record of recent errors. You can record a complete data log and review it later. To understand why a machine is cutting out, these recordings are more valuable than any guesswork.

Several controllers communicating with each other

On a dual-motor scooter, two VESC controllers can be connected via a communication cable. One controller receives the throttle signal and relays the commands to the other, and the VESC Tool allows you to configure both controllers from a single connection.

The limitations of the VESC

• It's important to know how to adjust it. A current value that is too high may not be immediately obvious: it can damage the battery, cause the motor to overheat, and ultimately lead to a breakdown.
• The hardware varies from one manufacturer to another. The firmware is the same, but the quality of the components, the cooling system, and the soldering are not. As with any controller, a stated current should be read with caution: is it a peak current for a few seconds, or a sustained current?
• The original display and controls may not always be compatible. The displays on commercially available scooters typically use the language of their original controller; a compatible display or an adapter is required.
• The scooter's manufacturer's warranty is generally void after a controller change.

Getting Started with a VESC: The Steps

Here's the order for an initial setup. Each step deserves its own detailed guide; this provides an overview.

1. Check the hardware. The controller must be able to handle the battery's full charge voltage with some margin, and its current ratings must match what the battery and motor can handle.
2. Install the VESC Tool on a computer or phone, and connect the controller via USB or Bluetooth (using a suitable module).
3. Update the firmware if the VESC Tool offers this option, before making any adjustments.
4. **Start the motor detection**, with the wheel raised, ensuring that nothing is touching the wheel.
5. `Setting Limits: Motor and battery currents, cut-off voltages, temperatures.`
6. Adjust the throttle and brake using the VESC Tool assistant, which learns their travel range.
7. **Perform an initial test by lifting the front wheel,** then at low speed on a clear surface, while monitoring the temperatures.

And what about the law?

A VESC is neither inherently prohibited nor authorized; it's simply a controller. However, in France, an electric scooter that operates on public roads must be factory-limited to a speed of 25 km/h. Performance settings are intended for use on closed circuits and private property.

Do you prefer a ready-to-ride system?

Not everyone wants to spend evenings tweaking settings in a software program. That's the idea behind our RageLink controllers: designed and manufactured in France in our workshops, they can be configured, updated, and locked from an app on your phone, with a display and telemetry that use the same language. They are not yet for sale; the waiting list is open.