Electric Cars and Regenerative Braking

Electric cars and regenerative braking
Electric cars and regenerative braking

Even though many of us automatically assume that it will be new car technology and new battery technology which pushes the electric car industry into the mass market, there are a number of small tweaks which have been made which will prove very useful. Regenerative braking is something which many of us will have come across, perhaps without even knowing. It is now commonplace in Formula One and is a very simple, but very effective way, of harvesting kinetic power which normally disappears from the vehicle.

What is regenerative braking?

Regenerative braking is simply the process by which kinetic energy (often in the form of heat) is harvested when a vehicle slows down during normal use. In traditional cars where there are no regenerative braking systems much of the energy is lost when heat is created, which ultimately affects the efficiency of the vehicle. When you appreciate that a gasoline engine itself is only 20% efficient, i.e. only 20% of the fuel power makes it to the wheels, we can ill afford to lose any more energy during braking.

As a consequence, a number of companies around the world have created regenerative braking systems which effectively, in some shape or form, harvest the energy lost upon normal braking. The systems are slightly different in traditional vehicles which harvest the heat created when the brakes are used, compared to electric vehicles which effectively reverse the electric motor cycle used to power the vehicle thereby recharging the batteries.

Does regenerative braking make a difference?

When you bear in mind that a "good" electric vehicle will probably get you around 100 miles per full charge, any improvements which can be made will have a significant impression. It is difficult to put an exact figure on regenerative braking because it depends when it is used (it is more effective in stop start situations) as well as the technology and system in place. However, if we err on the side of caution and suggest that regenerative braking could make a 10% difference to your journey capacity, by retaining battery charge, this would be an additional 10 miles per full charge.

Quote from ElectricForum.com : "The Toyota Prius is one such vehicle which uses this type of regenerative braking but what kind of impact can it have on battery power and efficiency of electric vehicles?"

This may not seem an awful lot when your journey capacity is only 100 miles per full charge at the moment, but can you imagine the difference when your journey capacity is in excess of 300 miles? It is also worth noting that various figures have been suggested in relation to regenerative braking energy efficiencies on vehicles such as trains and buses, with estimates of a 30% plus leap in additional capacity.


The technology and battery power associated with the electric car industry is obviously the main driver going forward. However, regenerative braking, aerodynamics and the type of materials used for the bodywork can, and do, make a big difference as well.

At this moment in time, with 100 miles per full battery charge journey capacity not even commonplace, any additional savings which can be made will certainly help. Regenerative braking is a technology which is commonly used in Formula One to great effect and is certainly beginning to filter down into the automobile mass-market, with the likes of the Toyota Prius already utilising such systems.