Racing powertrain: a motor, controller, and battery designed as a complete system

The powertrain, or "drivetrain" in English, refers to everything that makes an electric machine move: the motor, the controller that drives it, the battery that provides the power, and everything that connects and monitors them. In a racing machine, these components cannot be chosen independently. A very powerful motor paired with a battery that can't keep up, or a controller that overheats after three laps, will not lead to victory. That's why we consider them together, and here's how.

The weakest link determines the outcome

Imagine a chain: the motor can handle a high current, but the controller can't provide it; or the controller can provide it, but the battery collapses and its protection system cuts out. In all cases, the weakest link limits the performance of the entire system. And in racing, this weak link is often heat: a component that can last for two laps at full power, but not eight, is simply not up to the task.

That's why we design a powertrain based on its intended use: the track, the duration of the races, the weight of the vehicle and the rider, and the regulations. Then, we select each component to ensure that none of them are operating at their limit before the others.

The motor and voltage: speed

An electric motor has a speed constant, denoted as Kv, which indicates the number of revolutions per minute it produces per volt applied, when unloaded. For the same motor, the higher the battery voltage, the higher the maximum speed. Therefore, the choice of winding and the voltage are interconnected. Our guide on Kv, Kt, and motor poles explains this; on an electric scooter, this is the key factor in choosing between a high-speed motor and a high-torque motor.

In competition, the regulations often set a limit: in E'trott Racing, the battery voltage measured must not exceed 92.40 V in 2026, which corresponds to a maximum of 22 cells in series. Therefore, the motor must be wound to achieve the desired speed at this voltage.

The controller and current: torque

The torque of a motor, which is its rotational force, is proportional to the current flowing through its windings, the phase current. The controller is responsible for generating this current from the battery. To achieve strong acceleration, you need a controller capable of providing a high phase current without overheating beyond its limits throughout the ride.

The controller must also be configured specifically for this motor: its detection parameters, its current limits, and its thermal protections. A powerful controller that is improperly configured can cause the motor to overheat or cut out at the wrong time.

The battery: current and energy

The battery must perform two functions: provide the current requested by the controller without its voltage dropping, and contain enough energy to complete the ride. These two qualities depend on the chosen cells and their number. A battery that is too weak in terms of current will cause the voltage to drop with each acceleration, and then trigger the protection of its Battery Management System (BMS), resulting in the classic "cut-off," as explained in our guide on batteries and BMS systems that cause cut-offs.

The battery is also the heaviest component. In E'trott Racing, the category depends on the weight of the machine (38 kg for the limit between the Light and Racing categories, with a maximum of 65 kg in the Racing category): therefore, each additional cell must be justified.

Heat: The real limiting factor in racing

The motor, controller, and battery all convert some of the energy into heat. On the road, breaks allow them to cool down; on the track, they operate at full power for several minutes continuously. The E-scooter regulations prohibit liquid cooling for motors and controllers: everything must be cooled by air. This encourages the selection of components that don't operate at their limits, careful attention to airflow, and power adjustments where it truly matters.

The connection between the components: communication and data

A modern powertrain doesn't just consist of three power components. The controller, the battery's BMS (Battery Management System), the display, and the telemetry system exchange information: temperatures, voltage, current, and error codes. This communication allows for the protection of the entire system (reducing power before an element overheats) and for the analysis of each ride. The E-scooter regulations govern this data acquisition; see our guide on telemetry in racing.

The example of the Power Train 2027

This logic has guided our racing machines since 2023, and it led to the development of the RM290 motor in 2025, designed for the 2026 season and reserved for our customers. The machines equipped with this motor won three out of four races and secured the 1st, 2nd, and 4th positions in the 2026 championship. The RM290 is handcrafted in France; the entire production run has been ordered, and orders are currently closed.

For the 2027 season, the workshop is preparing the Rage Mechanics Power Train: six components designed and tuned together (motor, controller, battery, display, TelemetryBox, and a braking system called E-Draubrake), compliant with the E'trott technical regulations, with a racing service for preparation, tuning, and support throughout the season. They are connected by RageLink, our system of controllers, displays, and telemetry. The Power Train is currently available on a waiting list.