Regenerative braking: what is it and how does it work?

May 24, 2022 by

If you’re in the market for an electric car, you may have heard about regenerative braking during your research. But what is regenerative braking and how does it work?

In simple terms, regenerative braking takes your vehicle’s otherwise wasted kinetic energy and turns it into electricity. This system is commonplace in electric and hybrid cars, and many modern internal combustion engines also use regenerative braking to increase efficiency.

Keep reading for all you need to know about regenerative braking, how it works and how it may affect your experience behind the wheel.

What is regenerative braking?

Regenerative braking essentially recoups the kinetic energy (the energy an object has while it’s in motion) of a car as it slows down by converting it into electricity. In the case of electric and hybrid cars, this energy is stored in the battery to be reused whenever required.

While most talk of regenerative braking centres around EVs, it is often integrated into modern petrol and diesel cars as well. However, in these cases the recouped energy is generally used to power auxiliary systems like the power steering and air conditioning units.

How does regenerative braking work?

The way that regenerative braking harnesses this otherwise wasted energy is through the car’s electric motor. As the vehicle slows down the motor spins in reverse, sending energy back into the battery.

Petrol and diesel cars will have a smaller dedicated electric motor integrated into the drivetrain to recoup this energy, and as a result the benefits are not quite as marked as you get in an electric or hybrid vehicle.

What does regenerative braking feel like?

You often hear of ‘one pedal driving’ when people refer to electric cars, this is because the effect of the regenerative braking system can often feel like you have just stepped on the brake pedal as soon as you stop accelerating.

In some cases, you can drive around using just the accelerator pedal and rely on the regenerative braking system to slow you down. This can take some getting used to and most manufacturers allow you to change the severity of the braking effect. In the most aggressive setting, you may find that you hardly have to touch the brake pedal on your commute.

Some hybrid cars can also offer a strong braking effect although this tends to be more pronounced in plug-in hybrids and less so in mild hybrids, as they have smaller batteries and electric motors.

In a petrol car you are even less likely to feel the effect of the regenerative braking system, with most systems feeling like the car has been left in a high gear as you step off the accelerator.

What are the pros and cons of regenerative braking?

Pros

  • It extends the range of your electric/hybrid car and can increase the efficiency of your petrol/diesel vehicle
  • Brake pad wear is minimised, especially in city driving
  • ‘One pedal’ driving in electric cars makes driving them in traffic even less of a chore

Cons

  • Regenerative braking systems vary in feel and efficiency
  • It can take some time to get used to the way the system operates
  • In some cars, the brake pedal can feel strange as the car switches from the regenerative braking system to the hydraulic brakes.

Regenerative braking provides the best results in flowing city-style driving, where it can make the most of the regular changes in speed.

It is less efficient in slow stop-and-go traffic where it will have very little kinetic energy to work with. The same applies to long steady-speed motorway drives.

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