Sunday, May 15, 2011

Right or Left Pedal? Where Do You Want Your Regen?

One of the great features of electric cars is the regenerative braking. It really enhances the driving experience as well as extending your driving range as it captures the energy that would normally be wasted when you need to slow down. With conventional braking, the energy produced simply turns into heat and is wasted, whereas the regenerative braking systems in electric cars turns the energy into electricity and puts it back into your battery.

This is something that most people would never even think of and really have no use for when driving an internal combustion engine vehicle. You've got all the energy you need squishing around in your gas tank waiting to be set on fire so it can release that energy and propel the vehicle. However electric cars need to be as energy efficient as possible since they can only store a limited amount of electricity without becoming prohibitively expensive and heavy, since the more batteries you carry the more the car will cost and the more it will weigh, and decrease the vehicles efficiency.

Most people I know are a bit apprehensive when they first drive a car with regen. If the regen is activated by the left(or normal brake) pedal then you probably won't too notice much of a difference. However if you drive an EV with right (accelerator) pedal regen than your initial impression is probably that it definitely feels wrong, especially if it has strong regen like the MINI-E does. After driving your whole life in a car that doesn't have it, it really seems unnatural.

However after driving with it for only a short while, I came to really love it. Now, when I drive a car that doesn't have regen, I feel like somethings missing. I have driven cars with both right and left pedal regen and I definitely prefer to have it actuated by the right pedal. I can really do about 90% of my driving with one foot and it makes the driving experience a bit more sporty in my opinion. Slowing down for a curve in the road or to keep a safe distance from the car in front of you only requires you to gradually back off the accelerator. If you need to slow down more quickly, then just back off the accelerator completely and the regen fully engages and slows you down pretty quickly while sending some juice back to the battery pack. Of course if it's a situation that requires you to stop really abruptly, you always have the mechanical brakes to step on and quickly come to a halt.

Most people I know that have EV's say they prefer right pedal regen, and BMW believes that having it on the right pedal is the way to go also, as the MINI-E and the soon to be released ActiveE both have their regen on the right pedal. There are some people out there that have stated their opinions to the contrary though and say they want EV's to be as much like their gas powered cars as possible, and want all the braking, regenerative included, on the left pedal.

I believe that most people, if given the opportunity to drive an EV with right pedal regen would choose it over left and most of the people calling for it on the left pedal simply haven't driven a car for any period of time with right pedal regen, because if they did, they would prefer it that way.  Anyone care to chime in on this debate?


  1. I would like to keep the most aggresive setting possible on the go pedel. I'm ok if it has a selecteble level as long as I can dial it up to it's most aggresive. I also would want it on my brake pedel if possible as it is on the prius. So my answere is both and as strong as possible!

  2. I've driven a Tesla Roadster and I loved the feel of the regenerative braking. I think I would like to keep it on the right pedal like Tesla has incorporated.

  3. Safety first! Type A regen please, that's what they call right pedal regen.

    And, crank it up as high as the batteries and handling can take, anything else would be irresponsible and unsafe!

    How many times have you needed to stop quickly? In the Tesla the regen is instant so in an emergency, the car is already slowing hard before you even touch the brake; like I said Safety first.

  4. right is right, left is wrong. anyone that has driven an ev will tell you that

  5. Right pedal regen is simply better. The complexity of mixing mechanical and electronic braking on the left pedal numbs brake feel making it artificial.
    Motor = Right.
    Brake = Left.
    Keep it simple = Keep it responsive.

  6. I have to agree with everyone else. Definitely on the go pedal. I wouldn't mind if it was ALSO on the brake pedal to capture even more energy, but the primary regen should always be on the go pedal.

  7. Not having ever driven an EV for any length (I have driven a Volt about 2 miles), I can't weigh in from an informed personal experience view.

    However, I think the way you describe your own experience should be the way most people ought to experience things. People need to give time to adjust to regen in the "gas" pedal in an EV. If they have an open mind, and give it time, they'll end up liking it, I'm guessing.

    Showing my ignorance here, but does the LEAF have right-pedal regeneration?

  8. Christof:

    The LEAF has it on the brake pedal, like the Prius. Just about everyone I know that has been driving EV's for a while now strongly support it on the right or "go" pedal.

    There were a bunch of comments here all in support of right pedal regen, but Blogger had some technical difficulties yesterday and temporarily removed this post and even shut down access to many blogs. When they resumed and reposted this all the comments were removed which was unfortunate because there was quite a discussion here. Tesla has right pedal regen as does the MINI-E and BMW is sticking with right pedal regen on all their future electric vehicles, I've spoken to a few of their engineers about it. I like how it feels, and I like the fact the the brakes are still just a simple mechanical device, and not complicated by the regen. Toyota has problems with the Prius because of the regen software issues. Keep the brakes simple and use them only to decelerate rapidly in emergency-type situations.

  9. On the right pedal. No contest. Ask anyone that has owned an electric car with right pedal regen and 100% of them will tell you they want it that way

  10. Tom,

    I want the regen on both pedals. On the right pedal there should be the MINI E typical strong regen.

    By touching the left pedal slightly the regen should get even stronger till the maximum level possible is reached for regenerative braking. With a harder push of the pedal the conventional brakes should join to achieve the demanded deceleration.

    I gave a clear description of the regenerative braking to all persons that had a chance to make a test drive with my MINI E. So none of them was surprised by the effect the regen has. Although they found the regen unusual, nearly all of them told me that braking with the gas pedal is a good idea and liked it.

    So it is just a matter of experience to get used to it. But then you like it and won't miss it.

  11. Of course right pedal regen is best, and it does simplify the foundation brake system. But it also complicates the traction control, if they do it right. (In my opinion, they did not deal with traction control well in the Mini E but that was a prototype.)

    The Think EV does regen "correctly", on the velocity pedal. But regen is weak compared to the Mini E. Then again I hear all EVs have weak regen compared to the Mini E.

    Down here in Guilford county NC we don't have many hills so I should get used to the mild Think EV regen. But anyone in a hilly place would really appreciate the strong ACP regen in the Mini E. I found it made hills irrelevant to range, which is not what I hear about the Leaf.