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Clean Transport

Published on September 30th, 2018 | by Steve Hanley

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Regenerative Braking Is One Of The Joys Of Driving An EV

September 30th, 2018 by  


If you pay $1 million or more for a car, maybe you expect it to have a few quirks. Maybe, like the famous McLaren F1, it has the driver’s seat in the middle with a passenger seat on either side. Maybe it has the emergency brake on the left instead of the right, or uses an old-fashioned dimmer button mounted on the floorboard for the high beams.

But if you are transitioning from a conventional car to an EV, you want it to look, operate, and drive pretty much like every other car you have ever driven.

Nissan LEAF EV

The turn signal stalk and headlight controls should be on the left. The wiper control should be on the right. The heat, air conditioning, and audio controls should all be in the center of the dash. The spacing between the accelerator and the brake pedal should be the same as you are used to. No one wants to go searching for the brakes when an emergency occurs.

The Joy Of Regen

Electric cars today really do look, feel, and drive very much like their gasmobile cousins — except for one thing. They all have some form of regenerative braking that puts some electricity back in the battery when the car is coasting or when the driver applies the brakes. That is one aspect of the EV experience that is different and it takes some getting used to.

Different manufacturers approach regen differently. In the Chevy Volt, there is an extra paddle mounted behind the steering wheel below the turn signal stalk. Pull it towards you for more regen. Leave it alone for less. In the Chevy Bolt, there is light regen while coasting if the transmission selector is set to D, more if you put it in L.

Tesla and Jaguar allow the driver to pre-select the amount of regenerative braking preferred, but make it difficult to alter the setting while driving. The I-PACE electric SUV I drove in Portugal earlier this year has strong regenerative braking as its default mode. The Honda Clarity plug-in-hybrid I drove in August has several different settings that can be controlled by a button on the steering wheel.

The Nissan LEAF I purchased at the end of August has two modes. Set the transmission to D and there is very little regen braking until the driver touches the brake pedal. Change the setting to B and regen begins as soon as the accelerator is released. D is great for highway driving where you don’t necessarily want to slow down a lot when you lift off the throttle. B is perfect for around-town driving.

Every electric car has a range indicator. No one ever wants to run out of battery power, so range is displayed prominently on the dashboard so that you have to be totally oblivious to drain the battery completely. In the LEAF, lights start flashing with about 15 miles of range left. You would have to be brain-dead to miss the cues to find a charger ASAP.

So, what is so great about regenerative braking? Basically, it recaptures some of the kinetic energy in your car and puts it back into the battery so that you can drive further before you need to recharge the battery. Regen really isn’t about braking at all. One of the unique features of an electric motor is that it can be both a motor and a generator. When it is in generator mode, it actually slows the car down just as if you had shifted to lower gear in a conventional car.

One-Pedal Driving

If the motor slows the car firmly enough, it can make using the mechanical brakes virtually unnecessary. In some cars, like the I-PACE, you can take your foot off the throttle and let the car coast to a complete stop without touching the brake pedal.

The LEAF doesn’t work quite like that, but once you learn to plan ahead a little, you can get to the point where you need just a light tap on the brake pedal to bring it to a halt. Nissan claims the new LEAF with E-Pedal is capable of true one-pedal driving.

The result is, whether the car comes to a stop on its own or needs the mechanical brakes to shed the last 5 mph of speed, wear and tear on the car’s braking system will be greatly reduced. Paying less for brake pad replacement and brake repairs is one of the reasons the overall cost of ownership for an electric is less than for a conventional car. Of course, the fact that electricity is roughly half the cost of gasoline is a big part of that equation as well.

After driving the LEAF for two months, I find I use the B setting almost all the time. Provided I don’t have another car on my back bumper, I have learned to lift off the throttle earlier than I would in a conventional car and let the regen slow the car. Lots of times, I never have to touch the brake pedal at all while driving,

Regen & Range

Using regenerative braking has a definite influence on range. Often, I will see my range actually increase while driving as the motor puts energy back into the battery. While driving a conventional car for years and watching the gas gauge go down, down, down, I sometimes found myself wishing it would go back up once in a while. With an electric car and regenerative braking, that actually happens. It’s a pretty sweet feeling when it does.

Regenerative braking is one feature of electric cars that people who have never driven one before will need to adapt to. But it’s an effortless transition and once you get the hang of it, you definitely miss it when you drive a conventional car again. Our grandkids may never drive a car that doesn’t have regenerative braking, and that’s a good thing.


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About the Author

Steve writes about the interface between technology and sustainability from his home in Rhode Island and anywhere else the Singularity may take him. His muse is Charles Kuralt -- "I see the road ahead is turning. I wonder what's around the bend?" You can follow him on Google + and on Twitter.



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