Torque Shop: Upgrading EV brakes will not have any effect on energy recuperation

Is it a good idea to upgrade the brakes on my electric vehicle (EV)? I have seen some advertisements for aftermarket braking systems for EVs. Besides improving brake performance, do they also increase regenerative energy recuperation?

The front brakes on most EVs tend to be larger than those on comparable internal combustion engine (ICE) cars. There are two main reasons for this.

First, electric motors that power EVs deliver instantaneous torque, making them highly responsive to the throttle pedal. An EV’s acceleration, even from a standstill, can surprise most drivers not used to high-performance cars.

It is, therefore, crucial that EVs are equipped with brakes to cope with the acceleration in order to slow them down quickly after attaining higher than average speeds in a short time.

The second reason is that EVs are among the heavier passenger vehicles on the road. While an electric motor is roughly 100kg lighter than a similarly powerful combustion engine, the batteries in an EV contribute a significant 200kg to 500kg. So, a mid-sized family saloon weighs an average of 1,500kg, but an equivalent EV would be between 1,800kg and 2,100kg.

In addition, an electric motor can function as an alternator to produce electricity. This useful characteristic is used to “reverse” electrical energy flow from the motor into the battery. Singapore’s MRT trains use this capability to charge its on-board batteries.

On the move, with no throttle input or with light brake pedal pressure, the motor generates electricity to charge the batteries. Energy recuperation by this process loads the motor and gives the same effect as “engine braking” in a car with ICE. This is known as regenerative braking in EVs.

In many EVs, the intensity of regenerative load applied to the drivetrain can be varied by the driver to increase “engine braking” and commensurately increase the electrical energy produced for storage in the battery.

Conventional brake function takes over when more pedal pressure is applied to slow down quickly from high speed or to come to a complete stop. The hydraulic brake system – comprising the main components such as callipers, discs and friction pads – is no different from what is used on any motor vehicle.

In other words, the brakes for EVs do not possess any complex, high-tech feature that generates electricity.

Upgrading the brakes on an EV might improve braking performance, but will not have any effect on energy recuperation.