[Norton]

Now that the Bolt is out there getting tested by all the 'auto' and 'consumer' magazines we see paragraphs about '1 Pedal Driving', Using L, Regen Paddle, getting Max Regen, etc, etc,,,

These paragraphs never have a single sentence mentioning that driving the Bolt in D, just like a normal car, gets you the same amount of Regen with the Blended Brake Pedal.
Not one sentence.

A new person interested in buying an EV with no experience reads these reviews and thinks there is some new learning curve they must adopt to.

Chevy: Why don't these reviews ever mention that just driving the Bolt 'normal style' gets the same regen functions?
These magazines are not doing you any favors the way they go on and on about 'Regen'....
The Blended Brake Pedal is high tech engineering, and Tesla does not have it.

Then, the comparison reviews go on about, "Tesla has the best brakes of all EV's !!"

NO, they don't. The Tesla has the same old friction brakes as your grandfather's Oldsmobile.

They are just Friction Brakes on a Tesla. Tesla demands you adopt to this new '1 Pedal' style of driving to get regen.
Or, you can configure regen to minimum so you get something like 'coast' from a Tesla.
But then you turn momentum into brake heat, just like any old school car.

 

[Neromanceres]

I fully agree. The way GM has setup the braking maximizes regeneration no mater what mode you drive it in.

I watched the recent motortrend video where they brought the Bolt EV to Tesla. And the Tesla people wondering why the car can't be in L all the time and clearly not understanding at all how the brakes work on the Bolt EV.

 

[emv]

I'm going to presume the Bolt's brakes work in the same manner as the Spark's. With 30K on our Spark EV I can say that blended braking is THE way to go. Single pedal driving is more work and I get plenty of regen in two pedal. I find I drive smoother and get more range in D. L is great for going down steep hills but other than that, not for me.

I was astounded when I found out that Tesla didn't offer blended braking.

 

[Bacardi]

Agree with you fully Norton...

I will say with Tesla and the best brakes, are you sure they're referring to the "experience" and not performance whether shortest stopping distance or fade?

 

[Norton]

....they brought the Bolt EV to Tesla. And the Tesla people wondering why the car can't be in L all the time and clearly not understanding at all how the brakes work on the Bolt EV.

Funny! They need to get out of their ivory towers more often..

... Single pedal driving is more work and I get plenty of regen in two pedal. I find I drive smoother and get more range in D. ....

Exactly ! It's more work, and for what? The '1 Pedal' driving experience?
You have to keep your right foot planted on that GO Pedal for the entire trip.

With Chevy EV's you can have it both ways!

Sometimes a Gentleman has to shift his butt or make an 'adjustment'.
Hey, Tesla and i3 drivers: We know what you are doing when your brake lights come on and you slow down for no apparent reason.

...I will say with Tesla and the best brakes, are you sure they're referring to the "experience" and not performance whether shortest stopping distance or fade?

Don't know, don't care.
I'm talking about the gushing reviews about all-things-Tesla and never actually comparing engineering details with other EV options.

(Engineering detail: stopping distance is a product of tire traction and weight of the vehicle. If dinky little discs can bring a car to the onset of ABS, the brakes are doing their job.
Of course brake fade from flogging the brakes repeatedly is another matter.)

 

[Jeff N]

An interesting detail from Car and Driver's raw track testing sheets for the Model S60 in 2014 and the Bolt EV recently is that while the S60 stopped slightly shorter the first time it experienced some brake fade and after 2-3 emergency stops it took longer than the Bolt because the Bolt showed no brake fade. I'm guessing the Bolt's lack of brake fade is due to a substantial part of the braking being done through regeneration rather than friction even during hard stops.

 

[Chris TX]

The Volt/Bolt method of taking your foot off the accelerator to push the brake pedal to start deceleration, means you waste a fraction of a second to start slowing down. At higher speeds, this could mean 20-30 feet of additional stopping distance wasted. It could mean the difference of just scaring the crap out of yourself along with the pedestrian carrying a baby across the street and a horrible accident with your face all over the news for killing two people.

The Tesla one-pedal driving IMMEDIATELY starts deceleration when you take your foot off the accelerator.

Why would you want something else? With the Tesla, you set "Standard Regeneration" in the dash and it stays that way. If you want something like that on the Bolt, you have to select it every time you go for a drive. Oh, and if you remember to reach for the regen paddles during an emergency situation, you'll get that but only if you're going in a straight line. Good luck keeping that paddle pressed while you're turning the wheel to avoid something. And like several reviewers have said, big ugly shifter on a modern EV is stupid.

 

[Norton]

>The Volt/Bolt method of taking your foot off the accelerator to push the brake pedal to start deceleration, means you waste a fraction of a second to start slowing down. At higher speeds, this could mean 20-30 feet of additional stopping distance wasted. ...
The Tesla one-pedal driving IMMEDIATELY starts deceleration when you take your foot off the accelerator.
Why would you want something else? ....

>>Good luck keeping that paddle pressed while you're turning the wheel to avoid something. .....

>Why? Because it's the way cars have always been driven. There is no learning curve required. It's less work.
Someone could hop in a Chevy EV and immediately drive it just like a normal car.
Can't do that in a Tesla. You experience the 'Herky-Jerky' for a while. FUN !

If I need more braking than the 60kW of regen I get from the brake pedal of my little Spark EV, I have a seamless transition to friction brakes.
My foot is already on the Brake Pedal, just like a normal person, no "fraction of a second" if more braking is needed.

BTW, 60kW is the same amount of regen you get from a Tesla, but just on the rear wheels on a 1 motor model.
I suspect that has to be limited, on slick curves for example.

>>I agree about the regen paddle. It's 'Feature Creep'. Who needs it? It just complicates things. You don't want to burden the driver with thinking about how to slow down. It should come naturally.

Unfortunately Tesla didn't use their engineering to create a Blended Brake Pedal.
Drivers are forced to adopt this new "1 Pedal" driving style, and the associated last moment jabs at the brake pedal when 60kW of regen is not enough.

 

[Ladogaboy]

I'm not sure the Bolt and the Volt's braking is as bad as Chris TX is describing it. In fact, some comments make me wonder if Chris TX actually owns a Volt. I start up my car, set my mode to Sport and pull the selector back to L. Done. If I'm cruising and need to slow down, I simply relieve pressure on the accelerator, and the car starts to brake immediately. The way Chris TX is describing GM's braking setup reminds me of the way Rush Limbaugh described the "burden" of plugging our cars in every night.

 

[gpsman]

I think it is great the options we are getting in the Bolt. Sounds like Chevy really listened and provided features for us geeks to geek out on, but also the option to "just drive" like any other car. Win-Win. Stuff like the paddle for regen is fun, and potentially helpful on hills. I have a modified gen1 Honda Insight with a "paddle" for regen on demand and I love it. I also like that in my modified Insight I can turn regen OFF to actually gain speed while coasting downhill when desired. To me the ability to turn regen off on demand is just as important. Any hypermiler will tell you... coasting, neither consuming nor regenerating power is the greatest boost to extending range.

 

[Zoomit]

An interesting detail from Car and Driver's raw track testing sheets for the Model S60 in 2014 and the Bolt EV recently is that while the S60 stopped slightly shorter the first time it experienced some brake fade and after 2-3 emergency stops it took longer than the Bolt because the Bolt showed no brake fade. I'm guessing the Bolt's lack of brake fade is due to a substantial part of the braking being done through regeneration rather than friction even during hard stops.

Interesting observation. Looking at the Bolt EV test datasheet, the stopping distances actually decreased by a few feet over those 6 stops.

During panic stops the regenerative braking does have a minor effect on the brake energy needed to be absorbed by the friction brakes. But it may be less than you expect. Physics follows...

Assumptions:
3760 lbs
70-0 mph panic stop
no aero drag or other deceleration forces
regen averages 45 kW (a guess, it may start at 60kW but trails off as the car slows)
deceleration duration of 3 seconds
friction and regen brakes are applied at same time at start of deceleration

The total kinetic energy removed to stop the car is E = 1/2 * m * v^2, where:
m = 3760lb = 1705.507 kg (includes driver weight)
v = 70 mph = 31.2928 m/s

E= 835MJ or 232Wh

The regen brakes would remove 38Wh from the car [45kW * 3 sec/3600*1000]. So the regen brakes absorb 16% [38/232] of the kinetic energy and the friction brakes absorb 84% [194/232].

If we rerun all the numbers with a heavier car like the S 60 (4800 lbs), and leave everything else the same, the regen and friction brake usage changes to 13% and 87%, respectively.

So the friction brake design has by far the biggest effect on fading during repeated panic stops. The differences in regen brake calibration between EVs will only have a small effect on brake fading.

 

[Norton]

>...the stopping distances actually decreased by a few feet over those 6 stops.

>>... Physics follows...
....

> I wonder how that is explained? The pads were not bedded in? This was the pads' first time getting this duty?
Probably the LRR tires getting 'warm and fuzzy'!
I saw they had "PartDefeat and TracOff" but they still had ABS. You can't turn that off, correct?
Do they just mash the pedal and let ABS do it's job?

>> Awesome, thanks for doing the heavy lifting!

 

[Chris TX]

I'm not sure the Bolt and the Volt's braking is as bad as Chris TX is describing it. In fact, some comments make me wonder if Chris TX actually owns a Volt. I start up my car, set my mode to Sport and pull the selector back to L. Done. If I'm cruising and need to slow down, I simply relieve pressure on the accelerator, and the car starts to brake immediately. The way Chris TX is describing GM's braking setup reminds me of the way Rush Limbaugh described the "burden" of plugging our cars in every night.

Why would I lie about having a Volt? Do you seriously just not get on these forums enough to see what I do for other people's Volts, both Gen1 and Gen2? Feel free to click on the links in my sig. You might even see a few pictures of my Volt. I'm going off MY experiences with BOTH my Volt and Tesla. Driving the Volt in D, there is a delay in braking once you start letting off the gas. That delay isn't there with my Tesla that's always in "Standard Regen." That delay also exists in normal cars. What's wrong with removing that delay with the "one-pedal driving?"

Sure, go ahead and put your Volt in L and Sport everyday. But for the vast majority of people just want to put the thing in Drive and start driving, and like Norton points out, that's what they're going to do. Now, relying on the one-pedal driving for emergency situations isn't realistic and people will slam on the brake pedal with their foot.

Just do "one foot" emergency stopping maneuvers in D and then L while driving ~60MPH. See what the stopping distances you get with those tests. Do it three times in D and three times in L and average both sets. Make sure the brakes are cooled off between runs so there's no brake fade, which isn't an issue in emergency situations. You can't sit there and say there's not going to be a difference between the two sets.

 

[Ladogaboy]

Nobody said you were lying, Chris TX. My point is that you are describing how "inferior" the Volt's regenerative braking is compared to the Tesla's because Tesla defaults to your preferred while you literally have to hold the shifter a tenth of a second longer in the Volt (to put it in L). You are the only Volt owner I know who brings this up as an issue, but if you look at the results of impartial testing, your Tesla and Volt stop within 10 feet of each other in emergency braking (60-0 mph).

 

[Sean Nelson]

Sure, go ahead and put your Volt in L and Sport everyday. But for the vast majority of people just want to put the thing in Drive and start driving...

I don't own a Volt, so take my post for what it's worth. But I fail to see how it's any more difficult to shift from "P" to "L" than it is to shift from "P" to "D" after you start the car...

 

[Chris TX]

I don't own a Volt, so take my post for what it's worth. But I fail to see how it's any more difficult to shift from "P" to "L" than it is to shift from "P" to "D" after you start the car...

It isn't more difficult to do. In the Gen2 Volt, it's fine since the brake lights now come on when decelerating in L. The Gen1 Volt doesn't do that. In the Bolt (which is what this thread is about) you have to manually switch its regen every time you drive from the screen.

If my 2014 Volt's brake lights came on during deceleration in L, I'd use it all the time, and it would be just like my Tesla's one-pedal driving. You two guys are making the case for one-pedal driving on the Bolt, just like I am.

 

[Ladogaboy]

It isn't more difficult to do. In the Gen2 Volt, it's fine since the brake lights now come on when decelerating in L. The Gen1 Volt doesn't do that. In the Bolt (which is what this thread is about) you have to manually switch its regen every time you drive from the screen.

If my 2014 Volt's brake lights came on during deceleration in L, I'd use it all the time, and it would be just like my Tesla's one-pedal driving. You two guys are making the case for one-pedal driving on the Bolt, just like I am.

So now it's about the brake lights? Why don't brake lights come on in manual transmission cars when they downshift and compression brake? I'm pretty sure my Lancer EVO slowed down faster from 60 mph when I'd downshift to 2nd than the Volt (and possibly the Bolt) does under full regen. No brake lights came on then either.

If you're talking about emergency stops, then you throw one-pedal driving out the window. Maybe in a Tesla, you are willing to trust your life to its automatic braking, so you can just leave your foot on the accelerator. But a typical driver will move his/her foot from the accelerator to the brake pedal in either case, and that means the brake lights come on for both cars.

 

[Norton]

...Just do "one foot" emergency stopping maneuvers in D and then L while driving ~60MPH. See what the stopping distances you get with those tests. .... You can't sit there and say there's not going to be a difference between the two sets.

Excellent idea !!
Only it should be done from 70 MPH and this testing should be done by pros like the C&D staff so we have a known procedure, instrumentation and repeatability.
Unfortunately, this probably won't happen.

So us arm chair engineers just sit here and pontificate.
And I, for one, will "sit here and say there's not going to be a difference", due to Zoomit's physics example above !
All testing will involve the 'fraction of a second' to move your toes to the brake pedal, correct?

This is all about personal driving preferences and which EV manufacturer had the capability of creating Blended Brakes, thus giving the driver a choice.

I don't see this mentioned in the reviews. That's why there is this thread.

 

[Norton]

... In the Bolt (which is what this thread is about) you have to manually switch its regen every time you drive from the screen...

Say what? I thought it was like any other GM EV, you just put it in L for '1 Pedal'.

Are you confusing this with Tesla's method of configuring regen?

Do I need to read these reviews again?

 

[Sean Nelson]

It isn't more difficult to do. ... In the Bolt (which is what this thread is about) you have to manually switch its regen every time you drive from the screen.

Where did you get that idea? The Bolt uses one-pedal driving when it's put into "L" mode, which you access from the shifter just like in the Volt. And since you need to work the shifter every time you start the car anyway, I'm still not seeing why you think it's a particularly difficult thing to do in the Bolt.