The brake pedal

[bhzmark]

Our other car is a 2008 Prius. If you like being in control of the amount of regeneration, you're going to LOVE the way the Model S pedals work. You get significantly more control over the regen than you do in a Prius

So if you want more regen braking than simply standard level from releasing the accel how do you control that? In a prius you simply depress the brake the pedal. How do you get more regen braking in MS?

I suspect in the front wheel or awd teslas, they will capture more regen from the front braking action. Just can't regen brake very much from only the rear wheels in the MS.

 

[jerry33]

So if you want more regen braking than simply standard level from releasing the accel how do you control that? In a prius you simply depress the brake the pedal. How do you get more regen braking in MS?

You just modulate the accelerator pedal. Same as you would if you are driving a manual transmission car in second gear.

I suspect in the front wheel or awd teslas, they will capture more regen from the front braking action. Just can't regen brake very much from only the rear wheels in the MS.

Where did you get that from? Regeneration is limited by the amount the motors can regenerate and/or the programming and/or the amount of energy the battery can take. FWD or RWD makes no difference (AWD should because there are two motors). It's better than the Prius regeneration because the brakes and the regeneration are totally separate so you have far finer control over what happens. And don't forget that the Model S has larger disk brakes on the rear.

 

[Electric700]

The regeneration setting is listed on this configuration screen.

 

[PeterK]

So if you want more regen braking than simply standard level from releasing the accel how do you control that? In a prius you simply depress the brake the pedal. How do you get more regen braking in MS?

I suspect in the front wheel or awd teslas, they will capture more regen from the front braking action. Just can't regen brake very much from only the rear wheels in the MS.

There's plenty of regen. See the Mt Washington thread - I used the brakes on only two or three of the turns on the way down, and some drivers never touched theirs the whole way.

 

[kjl]

So if you want more regen braking than simply standard level from releasing the accel how do you control that? In a prius you simply depress the brake the pedal. How do you get more regen braking in MS?

Releasing the acceleration pedal all the way = full regen braking. 20% down (or so) = coasting with no accel and no regen. 100% down is full accel.

 

[bhzmark]

You just modulate the accelerator pedal. Same as you would if you are driving a manual transmission car in second gear.



Where did you get that from? Regeneration is limited by the amount the motors can regenerate and/or the programming and/or the amount of energy the battery can take. FWD or RWD makes no difference (AWD should because there are two motors). It's better than the Prius regeneration because the brakes and the regeneration are totally separate so you have far finer control over what happens. And don't forget that the Model S has larger disk brakes on the rear.

MS Regen is limited by the limited amount of braking that can be from the rear wheels. Cars that can regen from the front wheels can apply even more regen. They can apply so much regen that it can bring the car to a very quick stop without using the brake pads.

 

[bhzmark]

Releasing the acceleration pedal all the way = full regen braking. 20% down (or so) = coasting with no accel and no regen. 100% down is full accel.

What if you want more regen braking than just releasing the pedal? With the prius you can press the brake pedal and get additional regen on top of the regen from releasing the accel.

 

[kendallpb]

Ok. That explains it. I myself would not like this one pedal driving style; too much risk of pressing on the accelerator when an emergency braking situation comes up. Hopefully they can do a firmware adjustment for this item.

You have to try it to understand and you can't really predict how you'll like it. Also, you don't press the accelerator to do regent braking so there's not much chance of hitting that by accident. ;-) You'd never press it to brake, so how would you hit it by accident to brake?

Also, despite what people say, unless you always have lots of warning and always decelerate over a longer than normal distance, you'd probably use the regular brake--just not nearly as much. I know some have "mastered" one-pedal driving, but for me (maybe because I drive, un, spiritedly ;-) ) . . . I doubt I'll ever stop using the regular brakes. I try to use the regen as much as possible, of course--that's only smart, since you get back power that way, extending your range.

Anyway, just my take on it.

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I like to control the level of regeneration when I brake; I do that regularly driving in my Prius. I think I will defer to you guys since you know the model S better than me.

P.S. The more you ease up on the accelerator, the more regen you get--so you do control it. It's not all-or-nothing, if that's what you thought. If you're careful, you can even coast.

 

[kjl]

What if you want more regen braking than just releasing the pedal? With the prius you can press the brake pedal and get additional regen on top of the regen from releasing the accel.

So it sound like the Prius is "release the pedal = 50% regen, press brake to get 100%"

Tesla is "release the pedal = 100% regen"

You can't get more than releasing the pedal because it's already at 100%. If you want more stopping power you step on the brake pedal to engage the physical brake.

I take it you haven't test driven the tesla yet? lifting your foot off the pedal results in aggressive regen braking - most passengers in your car will assume you're pressing the brake, even though you're not.

 

[kendallpb]

What if you want more regen braking than just releasing the pedal? With the prius you can press the brake pedal and get additional regen on top of the regen from releasing the accel.

Heh. I have no idea how much regen the Prius gives versus the Model S, but isn't it limited to a certain amount, then your real brakes kick in? You don't get unlimited regen by just mashing the brakes harder, from what I've read anyway.

Well, it's not like the Model S's "let go of accelerator" gives you just what you get in the Prius doing the same thing. I don't know which car has more, but the difference is that all the regen is controlled in one place. It doesn't mean you get less or more, or less or more control. Just that it's controlled from a different place.

(You make me curious what the max regen of the Prius is, and for the Model S.)

 

[bhzmark]

Both cars will give strong regen from simply releasing the accel. The prius can additionally apply more regen to actually stop the car quickly with regen from the brake pedal slowing the front wheels.

The ms standard regen is about the same slowing effect as the prius in b gear mode. Both will slow the car quite strongly. But the prius can then on top of that slowing power, in addition to it, also get additional regen by applying the brake pedal to use regen (not the brake pads) to bring the car to a quick stop.

If that same braking effect was applied to the rear wheels (either by dialing in more regen from releasing the accel, or from engaging the brake pedal) the rear wheels would likely lock. The amount of regen from the rear wheels is less than available from the front wheels.

 

[vfx]

It's very much like a golf cart when you let off the pedal. One foot driving and only the occasional brake foot depression.

 

[Doug_G]

MS Regen is limited by the limited amount of braking that can be from the rear wheels. Cars that can regen from the front wheels can apply even more regen. They can apply so much regen that it can bring the car to a very quick stop without using the brake pads.

I've yet to see any car where the regen level is anywhere near the traction limit of the rear wheels. So this statement is irrelevant. The Model S has very strong regen and it decelerates the car quite quickly.

 

[markb1]

I'm pretty sure the Model S can absorb more regenerative braking energy than a Prius, but it's a heavier car, so it's necessary to absorb more energy to stop a Model S in the same distance. It doesn't have anything to do with which pedal it's associated with.

 

[montgom626]

Hi,

I heard a few cases when people have said that they can drive the Model S by only using the gas pedal, and I always wondered why they do not use the break pedal normally. Can't the break pedal also control regenerative breaking, or is that out of the question in the Model S?

Go drive a Model S and you will answer your question or a Volt as it does the same thing.

 

[Hengist]

Tesla can regenerate at max rate of about 60 kW. Prius shows you a regen symbol for each 50 Wh of regen, the regen braking max rate is 20 kW per http://techno-fandom.org/~hobbit/cars/b-mode.html. A Volt captures up to 60 kW combining L setting and brake. The model S can recapture roughly three times as much energy as a Prius, about same as Volt.

 

[twinklejet]

A bit rude, no?

English is not everyone's first language.

Perhaps a little and I apologise if it offended anyone. Was trying to put a point across in a way such that the poster would not simply glaze over my post (so it had to be curt and to the point)..
Too many people are confusing the brake with break and subtle efforts to correct them weren't working... Never stop learning, no?

Anyway, I did add a smiley face to reduce the effect... and I did welcome him... I wasn't trying to be offensive or anything :frown:

 

[brianman]

Give this guy a Brake (break)! Some people have english as a 2nd language. They have to take a break from their first language to talk about braking. His first language is likely not broken. So give it a break.

Way to put the brakes on that detour.

 

[jerry33]

What if you want more regen braking than just releasing the pedal? With the prius you can press the brake pedal and get additional regen on top of the regen from releasing the accel.

But the amount of braking you get on the Prius' accelerator pedal is minimal. Nothing like the Model S. And you can control the regen far better in the Model S. Remember, with the Prius' system you always get some friction braking, and you can't really control how much. In the Model S, you only get friction braking when you press the brake pedal. It's really a far better system. (150,000 miles of Prius driving)

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Tesla can regenerate at max rate of about 60 kW. Prius shows you a regen symbol for each 50 Wh of regen, the regen braking max rate is 20 kW per http://techno-fandom.org/~hobbit/cars/b-mode.html. A Volt captures up to 60 kW combining L setting and brake. The model S can recapture roughly three times as much energy as a Prius, about same as Volt.

Might be 90 kW. Look at the gauge closely and you'll see that it goes past 60, even though 60 is the last number.

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Both cars will give strong regen from simply releasing the accel. The prius can additionally apply more regen to actually stop the car quickly with regen from the brake pedal slowing the front wheels.

The ms standard regen is about the same slowing effect as the prius in b gear mode. Both will slow the car quite strongly. But the prius can then on top of that slowing power, in addition to it, also get additional regen by applying the brake pedal to use regen (not the brake pads) to bring the car to a quick stop.

1. The Prius' regeneration on the accelerator pedal is very weak.

2. B Mode adds engine braking to the mix, it decreases the amount regeneration available by turning some of the kinetic energy into engine heat. Here are the numbers courtesy of Wayne Brown:

W

B> I took my lunch hour today with a Taco Bell Burrito in one hand and
WB> the 2004 Prius steering wheel in the other and did some
WB> more "D," "B" & "Braking" tests. Here are the results.
WB>
WB> <><><><><><><><><><><><><><><><><><><><><><><><><><><>
WB> All of the following records are data captures that occurred from 50
WB> MPH to 10 MPH. Each record is the result of the average from 3
WB> separate runs:
WB>
WB> Mode.........Amps.......Seconds........Cumulative w/h
WB> Braking.......90...........9................54.03
WB> Braking.......70..........15................64.38
WB> Braking.......60..........19................71.01
WB> D.............18..........51................59.50
WB> B.............26..........30................48.35
WB>
WB> It is interesting that in this test, "B" is almost 19% less
WB> effective than "D."
WB>
WB> Of great interest however, is the "Braking @ 60 Amps" runs. This is
WB> by far the most efficient way to slow down a 2004 Prius. In fact it
WB> is almost 32% more efficient than "B."
WB>
WB> Here is a table that illustrates the several common ways we slow the
WB> Prius down and their ratings in efficiency percentages. "Braking @
WB> 60 Amps" is the most efficient way to slow the 2004 Prius down;
WB> therefore it is the 100% baseline or benchmark against which the
WB> others are compared:
WB>
WB> Mode.....................Efficiency
WB> Braking @ 60 Amps...........100%
WB> Braking @ 70 Amps............91%
WB> D............................84%
WB> Braking @ 90 Amps............76%
WB> B............................68%
WB> N.............................0%
WB>
WB> Long story short; run out and practice light braking from 50 MPH to
WB> 10 MPH until you have it down to 19 seconds on smooth level
WB> roadways. By this you will learn what "Braking @ 60 Amps" feels
WB> like and you too can become a super efficient, maximally efficient,
WB> 2004 Prius Operator while in deceleration!
WB>
WB> Regards,
WB> Wayne

 

[bhzmark]

But the amount of braking you get on the Prius' accelerator pedal is minimal. Nothing like the Model S. And you can control the regen far better in the Model S. Remember, with the Prius' system you always get some friction braking, and you can't really control how much. In the Model S, you only get friction braking when you press the brake pedal. It's really a far better system. (150,000 miles of Prius driving)

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Might be 90 kW. Look at the gauge closely and you'll see that it goes past 60, even though 60 is the last number.

- - - Updated - - -



1. The Prius' regeneration on the accelerator pedal is very weak.

2. B Mode adds engine braking to the mix, it decreases the amount regeneration available by turning some of the kinetic energy into engine heat. Here are the numbers courtesy of Wayne Brown:

W

Prius drivers go 150k plus miles without having to do any maintenance to their brakes because they can use regen to do virtually all of their braking. It is a much lighter car so it needs less regen in kwh to have the same absolute deceleration. Do you see how comparing khw isn't relevant ?

Compare slowing from 60 to 20 in two seconds. Prius can do it with all regen,including regen from the brake pedal (but not the brake pads). MS has to use brake pedal too because merely lifting off the accel isn't suficent to slow that fast. Using brake pedal in the ms will always convert/waste energy as brake heat and never trigger more regen. That can be remedied with an awd drive or fwd car that allows the brake pedal to trigger additional regen on top of the standard accel release regen.



MS still has