What is regenerative braking and how does it work?

If you’re thinking of buying an electric car but haven’t driven one before, you might have heard or read the term 'regenerative braking' and wondered what it means.

Well, regenerative braking is one of several factors that make electric cars quite different to petrols and diesels to drive, and it's arguably the most significant. (The others include the lack of engine noise, the instant power delivery and the fact that there’s usually just one forward gear.)

That's because, if you choose to use it, regenerative braking can affect the way you drive. So, here we explain what it is, how it works and how it can benefit you and your car.

What is regenerative braking?

Commonly referred to as ‘regen’ braking, it's a process an electric car uses to regain kinetic energy that would otherwise be lost during braking. The energy is returned to the car's main battery as electricity so it can be used to drive the wheels.

Some hybrid cars have regenerative braking too. While the system is essentially the same as you’ll find in an electric car, they use it to help reduce the amount of fuel the engine needs to burn.

How does regenerative braking work?

The beauty of an electric motor is that it can run either forwards or backwards (or, strictly speaking, clockwise or anti-clockwise). In normal driving, the motor is rotating in the same direction as the wheel or wheels it drives, but under braking, it can spin in the opposite direction, generating energy. 

In a car with a combustion engine, when you press down on the brake pedal, hydraulic pressure pushes the brake pads on to the discs, creating friction and slowing down the vehicle. During the process, energy is wasted (although some new petrol or diesel cars now have a limited form of 'regen').

Most electric cars have a hydraulic system and regenerative braking. One benefit of having two braking systems is that it reduces the wear on parts, which can save you money and lower maintenance costs.

Are all systems the same?

In most cases, regenerative braking feels similar to hydraulic braking, but the car slows down as soon as you lift off the accelerator pedal (as it does if you drive a manual conventional car in a low gear to use engine braking). It can take some getting used to if you haven’t driven an electric car before.

The regen system in some models allows you to select ‘one-pedal driving’. You can use the system to slow the car without the need to press on the brake pedal. While all regenerative braking systems have the same basic function, some are adjustable so you can configure the strength of the braking.

In the Kia EV6 for example, you have five settings of regenerative braking, and you can switch between them using paddles behind the steering wheel. The lowest setting – called ‘0’ – switches the system off so you can use the hydraulic brakes as you would in a petrol or diesel car. There’s also ‘1’, ‘2’, ‘3’ or the maximum, ‘i-Pedal’. The i-Pedal setting is so strong that you hardly need to touch the brake pedal at all.

In the MG ZS EV there are only three settings, and you can select them using a switch on the centre console. In this instance, you have ‘Light’, ‘Moderate’ and ‘Heavy’.

Do all electrified cars come with regenerative braking?

Most new electric and hybrid cars come with some form of regenerative braking to help conserve energy. However, you can’t always adjust the strength of it.

So, if you’re looking to buy an electric car, it’s important to check what kind of regen system the car has before you drive it.

Can it improve my range?

Regenerative braking is an effective way of reducing a car’s energy consumption. So, if you’re looking to maximise the range of an electric car, using the strongest setting can help conserve more energy.

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