Model S Regenerative Braking is Different Than Hybrid Regen..Why?

[brianman]

In my opinion it gets too soft as the car slows down. It will not take you to a full stop. I think I would like that. I always have to use the friction brakes on the last foot or so.

Agree.

- - - Updated - - -

I have had my Model S for a few days now and I have now had time to learn more about how the car drives.

We've had threads like this a few times that I can recall and it's usually someone who hasn't gotten the car yet or hasn't driven it very long yet.

Can you please report back in two weeks? I'd love to hear if your opinion is swayed by driving it longer or not.

Either way, enjoy the car!

 

[stevezzzz]

One-pedal driving in rush hour traffic is one of the true joys of the Model S. It's a serene experience, relatively speaking. Putting regen on the brake pedal would be a huge step backward, IMO.

 

[invisik]

I appreciate the energy from regen, but it does not make for a very smooth stop and you can on vary the intensity of the regen to help the car to be ready to stop precisely where you want it to. (meaning I have to let off the pedal so many feet away from the stopping point to make it stop there... If I let off too early, too late, or have an incline of sorts, the distance to where I have to let off changes.....). This is difficult to evaluate and predict at every intersection. Using traditional brakes it is easy because you can vary the pressure on the brake to adjust on the fly the rate of deceleration and thus can make it perfectly every time.

I've never driven any other car with regen but the brake pedal based regen sounds good. Why can't this be a setting on the Model S? It's all software controller anyway...

The low regen setting is a decent middle ground as you always have to use additional brake pressure to control your deceleration and is less harsh.

-m

 

[Evbwcaer]

Thanks for all of the discussion. I will report back how/if my opinion changes over the next few weeks of ownership. As it stands now, I wish the regen was more like a hybrid where the first portion of the brake pedal only activated regen, not friction. This allows the choice between full, 100% efficient coasting, or regen. As it stands, the option to coast is there...sort of, you need to center the needle.

I just don't really get the "one pedal driving" point. I get the point of the thought, but in practice, don't you still need the regular brakes for the last couple of feet?

Does it come down to preference? Would you rather center the needle or be more of a two pedal driver.

 

[ecarfan]

I just don't really get the "one pedal driving" point. I get the point of the thought, but in practice, don't you still need the regular brakes for the last couple of feet?

You do, but not as often as you might think you will when you are new to the car.

 

[Incredulocious]

I've never driven any other car with regen but the brake pedal based regen sounds good. Why can't this be a setting on the Model S? It's all software controller anyway...

For what it's worth, you can experience a Tesla drivetrain with both accelerator-based regen and regen via the brake pedal... in the second generation Toyota RAV4 EV. It works well, but presumably is more complicated than just confining regen to the accelerator pedal. The hand-off from regen to friction braking is smooth and hard to notice, certainly more subtle than the LEAF. Presumably this comes from Toyota's many years of expertise with all their hybrid models.

Toyota decided to go with reasonably strong regen from the accelerator in the RAV4 EV (certainly more than the LEAF) but it's also dialed down from the Model S high setting. (I'm speaking of the secondary "B"/"Braking" mode of the RAV4's two drive modes, "D" and "B".) It's not strong enough to use to stop at an intersection with just lifting off the accelerator. Unfortunately it's been too long since my last Model S test drive to compare its low regen setting to the RAV4 I have now. I can say that it's enough to feel a strong "downshift", to control your speed in varying traffic conditions, over rolling hills or through twisty roads and to hold the vehicle to the speed limit on a 6% grade like highway 17 here between Santa Cruz and Los Gatos, CA.

I like the fact that the brake pedal takes advantage of regen in the RAV4, but perhaps I wouldn't miss it if the RAV4 had even stronger regen with the accelerator pedal.

 

[Canuck]

I just don't really get the "one pedal driving" point. I get the point of the thought, but in practice, don't you still need the regular brakes for the last couple of feet?

Usually yes, but it's still a lot less of using the brakes than in an ICE. Also, I do a lot of driving on a mostly single lane winding highway and I can go for hours without ever touching the brakes. As I go into winding turns, the regen slows me down enough not to have to touch the brakes. In an ICE, you have to brake. What bothers me is that the brake lights come on when regen is used past a certain point (you can see when the brake lights come on by putting your vehicle on the screen) so, unless the people behind me know about a Tesla, they must think I am riding the brakes, when in fact I haven't even touched them.

 

[invisik]

I just don't really get the "one pedal driving" point. I get the point of the thought, but in practice, don't you still need the regular brakes for the last couple of feet?QUOTE]

If you don't you certainly will as you get in the drove of driving the car. I have some intersections timed on my daily commute I don't hardly have to brake! You do have to regular brake right at the end, yes. Slow and Go traffic is great for one pedal driving, you'll find!

-m

 

[Evbwcaer]

If you don't you certainly will as you get in the drove of driving the car. I have some intersections timed on my daily commute I don't hardly have to brake! You do have to regular brake right at the end, yes. Slow and Go traffic is great for one pedal driving, you'll find!

Above really gets to my thought. Because with hypermiling, you don't have to center the needle. In the above circumstance, there is no difference compared to a hybrid except that you have to pay extra attention to your dash...centering the needle. Where is the upside?

 

[jdbob]

The Ford Energi cars have a combination of both. The brake pedal does use regeneration when it can and then uses the friction brakes.

Letting off of the acceleration pedal works differently depending on whether the shifter is in "D" or "L", which is a bad label because it's isn't low anything, it's high regeneration. In "D" it simulates a normal automatic transmission car. In "L" it uses regenerative braking, not sure how it compares to any other car though.

I found "L" very useful when I was stuck on California freeways last month during stop and go traffic. With a bit of practice I could do one pedal driving almost all the time, occasionally having to resort to use the brake pedal to come to a complete stop. Although it's not too useful around my little town because of the stop signs I would imagine it would work great in areas where they use roundabouts.

 

[Todd Burch]

I did a fairly complete analysis of this in this thread.

 

[rcc]

Speaking as someone used to driving sports cars with manual transmissions, I love strong regen and the (primarily) one-pedal driving. Strong regen may not be as efficient as brake-pedal regen but I find the one-pedal driving experience to be far superior to anything else out on the road today.

The S really is a driver's car.

And if you drive on the highway at 70 mph instead of 55mph, I suspect the difference in regen efficiency is noise compared to the energy cost of going 10 mph faster due to wind resistance.

 

[JohnQ]

Above really gets to my thought. Because with hypermiling, you don't have to center the needle. In the above circumstance, there is no difference compared to a hybrid except that you have to pay extra attention to your dash...centering the needle. Where is the upside?

You'll find that muscle memory, and seat of the pants feel, are such that you don't have to stare at the dash at all. I know when I'm neutral on the energy meter without a glance (or at least with just a confirming glance if I'm so inclined).

The upside is that in traffic I don't shift my foot. I simply modulate the pressure being applied. With the brake based regen I'm constantly shifting my foot between the pedals. It sounds like a small thing but to me it's one of the real pleasures of driving this car.

 

[ItsNotAboutTheMoney]

The Ford Energi cars have a combination of both. The brake pedal does use regeneration when it can and then uses the friction brakes.

Letting off of the acceleration pedal works differently depending on whether the shifter is in "D" or "L", which is a bad label because it's isn't low anything, it's high regeneration. In "D" it simulates a normal automatic transmission car. In "L" it uses regenerative braking, not sure how it compares to any other car though.

I found "L" very useful when I was stuck on California freeways last month during stop and go traffic. With a bit of practice I could do one pedal driving almost all the time, occasionally having to resort to use the brake pedal to come to a complete stop. Although it's not too useful around my little town because of the stop signs I would imagine it would work great in areas where they use roundabouts.

L is Low, following the old Low gear that ATs would have to provide engine braking for long downhill. But in a plug-in with high regen, it's just used to provide 1 pedal driving.

 

[Great Dane]

I Felt the same way about the regen as you do
But 1 month of driving I would not have it any other way.
Here is something else I do, I bump the stalk to neutral all the time
for great coasting and then bump it in drive to slow down or speed up again
1 pedal driving will grow on you quick

 

[Cottonwood]

Speaking as someone used to driving sports cars with manual transmissions, I love strong regen and the (primarily) one-pedal driving. Strong regen may not be as efficient as brake-pedal regen but I find the one-pedal driving experience to be far superior to anything else out on the road today.

The S really is a driver's car.

Exactly!

I describe the Model S or the Roadster as driving like a manual transmission car that is always in 1st or 2nd gear. If you want to coast or stay at the same speed, your right foot quickly learns the neutral position to maintain that. If you want to speed up, you push the accelerator more, if you want to slow down, you let up on the accelerator, and if you want to slow down faster, you push the brake pedal, just like a sports car that has been down-shifted for max performance.

I have driven several Toyota and Lexus hybrids that attempt to present a car with an automatic transmission and brakes with regen hidden underneath. Comparing those to a Tesla (Roadster and Model S), that does not hide the regen, I far prefer the Tesla model. It gives you the joy of the one-foot control of a manual transmission without having to deal with a clutch.

 

[gavine]

The part that takes getting used to is "feeding gas" to slow down less. You feel as though you are using energy just to not slow down too much, but you quickly learn the you are still charging the battery because of the regen meter being green.

 

[WarpedOne]

Here is something else I do, I bump the stalk to neutral all the time
for great coasting and then bump it in drive to slow down or speed up again

I wasn't aware you can do that while at moving speed?

 

[jerry33]

I wasn't aware you can do that while at moving speed?

You can do it, but it's really not worth it when controlling the pedal with your foot works just as well.

 

[HankLloydRight]

I also believe it's illegal in some (most?) jurisdictions to put a car in neutral like that.