Put simply, regenerative braking is the recovery of kinetic energy during braking. In electric cars, some of this energy can be harnessed by the electric motor for re-use. In theory, you should get more miles per charge.
This video produced by Bosch provides a visual demonstration of how regenerative braking works.
When the driver of an EV brakes, the electric motor switches from powering the wheels to generator mode. The generator then converts a portion of the kinetic energy into electric energy, which is stored in the battery.
In a pure electric vehicle, drivers will see an extended range, while hybrid car drivers will experience lower fuel consumption and reduced CO2 emissions.
It’s worth noting that regeneration doesn’t replace the traditional brakes. Before coming to a complete stop, or in an emergency situation, the standard disc brakes will take over to bring the car to a halt.
Is it as simple as that?
In short, yes. If you’ve ever been on the dodgems, you’ll know that a bumper car starts to slow when you release the ‘go’ pedal. It’s a similar story in an electric car, albeit without the opportunity to bump into your mates.
It takes a while to get used to regenerative braking, but once you do it becomes second nature. The fact that you’re improving the car’s electric range only adds to your feeling of satisfaction.
Regenerative braking is one of the key parts of eco-driving. Used effectively, it will improve your driving and allow you to travel further. For example, if you’re going downhill, easing off the accelerator pedal will activate regenerative braking, effectively offsetting the extra energy required for climbing the next hill.
Regenerative braking settings
In most electric vehicles, it’s possible to configure the regenerative braking via the car’s touchscreen media system.
For example, in the Jaguar I-Pace, you can select one of two settings: low or high. In the low setting, the deceleration is similar to the gradual braking effect you’d experience in a standard car. The Jaguar will travel further before stopping when the accelerator pedal is released.
In the high setting, you’ll experience a greater level of deceleration from the moment you release the pedal. There’s a similar system in the BMW i3, with BMW claiming the brake energy recuperation can increase driving range by up to 25 miles.
In theory, you can do more driving using nothing but the accelerator pedal. This is sometimes referred to as ‘one-pedal driving’.
Nissan Leaf e-Pedal
The Nissan Leaf takes the concept of ‘one-pedal driving’ to the next level. It features a so-called e-Pedal, which allows the driver to start, accelerate, decelerate and stop using only the accelerator pedal.
In the Leaf, the pedal itself is a standard affair – e-Pedal mode is activated via a switch on the dashboard. With the e-Pedal engaged, the pedal feels much firmer, allowing you to make more precise inputs. It takes a while to get used to, but once you do you’ll find yourself spending more time in ‘one-pedal’ mode.
The new Porsche Taycan could provide a glimpse of next-generation regenerative braking systems. It’s called Porsche Recuperation Management (PRM).
A front-mounted camera monitors the road ahead. If it sees the way is clear when you release the accelerator pedal, it will coast for longer. If there’s a car in front, it switches to regenerative braking.
Porsche says that up to 90 percent of the braking will be achieved via regeneration, but it wanted to present a more relaxed approach for high-speed driving. In other words, a sudden jolt when lifting off on a German autobahn is far from ideal.
Amazingly, Porsche also says that you could achieve up to a third of your electric range exclusively from recuperation. With regenerative braking from 124mph to zero, up to 2.5 miles of range can be recovered.
Regenerative braking is another bonus feature of electric car ownership. Although you’ll never recover all of the energy consumed moving the car forwards, harvesting some of it will increase your range.
The amount of energy recovered depends on the electric car in question, your driving system, the regeneration settings and the outside temperature. As an aside, with regenerative braking, you’re not producing any brake dust, which means you’re a little closer to achieving 100 percent zero emissions.