What is regenerative braking and how does it work?

As the impetus for electric vehicles (EV) continues around the world, proponents and sceptics alike are understandably paying plenty of attention to all aspects of EV technology.

In terms of going from go to whoa, regenerative braking in EVs has become a key talking point for a number of reasons, including efficiency of the technology in comparison to conventional braking systems; and overall benefits in terms of energy usage, environmental impact and brake system longevity.

With a conventional braking system, the act of planting your foot on the anchors creates friction between the brake pads and the brake disc and converts your vehicle's kinetic energy into heat.

Under deceleration, this heat/energy goes to waste because it has nowhere to go other than to be lost to the environment.

Regenerative braking technology works differently by recovering a proportion of the energy that previously would have been wasted.

Or as the good folk at Tesla explain it: "In a battery-powered electric vehicle, regenerative braking is the conversion of the vehicle’s kinetic energy into chemical energy stored in the battery, where it can be used later to drive the vehicle.

"It is braking because it also serves to slow the vehicle; it is regenerative because the energy is recaptured in the battery where it can be used again."

Sounds good, doesn't it, especially from the perspective of tackling energy waste and reducing environmental impact, both of which are such hallmarks of the EV mission.

The question is: how good is regenerative braking from a purely motoring perspective?

TALKING 'BOUT MY REGENERATION

Whether behind the wheel of an internal combustion vehicle, an EV or a hybrid, similar factors always come into play when determining economy, performance and range.

Driving conditions, driver behaviour, vehicle size and maintenance all have an influence, as does the yin-yang inevitability of energy created versus energy expended.

Regenerative braking is more effective in urban/suburban conditions where you need to do more braking and hence can take advantage of the stored energy in your EV battery system.

That is not the case if you're cruising along 100km of dead straight highway and hardly touching the brake at all.

Drive uphill and your brakes, whether regenerative or conventional, don't really feature; drive downhill and constant braking not only slows the car but regenerates energy and keeps the battery charged.

In hybrid vehicles, regenerative braking works alongside the conventional braking system and manufacturers such as Tesla, Toyota, Volkswagen and Mercedes are all using regenerative braking technology in their latest hybrid models.

If you're thinking of making the switch from the internal combustion engine to the new technology of electric and hybrid vehicles, AutoGuru has a number of articles with plenty of invaluable information.

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