Is coasting retarded like it is on the Roadster?

Is coasting retarded like it is on the Roadster?

I understand that on the Roadster, regenerative braking becomes active when the accelerator pedal is not pressed enough to maintain speed and that as a consequence, coasting functionality is retarded. I also understand that unlike the Toyota Prius, the regenerative braking in the Roadster is not in any way linked to the brake pedal.

Telsa has some very promising technology, but these are issues that impair the driving experience enough that every time I think about possibly getting one, I tell myself that it is not worth it because I cannot coast without having the regenerative braking activate.

Does anyone know if these issues have been fixed in the Model S or does Tesla Motor still consider them to be features? If they do consider them to be features, is it possible to turn them off?

Robert.Boston | November 25, 2011

@Mycroft: I like your "indent" point better than my "deadband" idea. Perhaps this issue is completely moot, but as you point out, we need something to talk about, and Tesla doesn't through any new crumbs for us to peck over!

cerjor | November 25, 2011

re: Brian H's comment

When I taught physics, I would tell my students that a car has three "accelerators." Then ask them what they were.

Brian H | November 26, 2011

goose pedal, brake, steering wheel.

Robert.Boston | November 26, 2011

Emergency brake, hand dangling out the window, convertible top? :-)

jbunn | November 26, 2011

Mary Catherine O'Malley, two swiped cans of Pabst Blue Ribbon beer from my grandpas stash, and the back seat???

Brian, I had to backspace a couple of times over "Gas Pedal". This is going to be a habit to break. A lifetime of saying things like "hit the gas" will be hard to break.

I think it's going to take even longer to get used to cerjor's "accelerator pedal", "other accelerator pedal", and "accelerator wheel".

For those of us who enjoy physics, there is an old article on the Tesla site that talks about the change in mass as you use the battery. On the roadster a few hundred miles will decreace the mass of the battery by about the mass of a grain of sand, only to be gained by recharging.

dborn | November 26, 2011

I believe the official term for the device to increase the rate of motion is called the "torque pedal". It won't change "put the pedal on the metal", or "floor it".

Mycroft | November 26, 2011

Sorry, but just like I'm still dialing a phone number, I'll be hitting the gas in my electric car. :)

Brian H | November 27, 2011

"Goose it!" So it's the goose pedal. "Accelerator" and "torque" pedal etc. are just to science-y. ;)

Kallisman | November 27, 2011

Brian H: What about calling it the power pedal? Cos it's regulating the the power, wether it goes to or from the motor. It also gives u the power to decide the speed.

Mike_ModelS_P457 | November 27, 2011

My father still calls his fridge an icebox, and I'm genetically as stubborn as him, so I'm going to call it the gas pedal out of tradition. Language is oftentimes divorced from the modern functional reality.

Golf is a good example:

I still call my woods "woods" despite them having no wood in them whatsoever. I openly mock people who refer to them as "metals."

Anachronisms abound. As long as people understand what you are saying you are probably good. Creating new language is far more complex than creating new products.

Brian H | November 28, 2011

I just think calling it the goose pedal would be a gas! (Which expression, I believe, is a hangover from the days when a genteel social get-together might include a shared laughing gas session ...). :D ;p

Getting Amped Again | January 4, 2013

I'm bumping this thread because I'd like to know if it's possible to coast in a Model S now that we have them out in the wild.

I get 19.1 mpg overall in a 6000 lb SUV because I'm an efficient coaster (highway off-ramps, distant traffic lights that change, etc.) Since coasting is more energy efficient that regen when you don't want to slow down (or want to very gradually slow down), I'd like to be able to control when I coast and how much regen occurs, with the ultimate goal of hardly ever using the brakes.

The Roadster owners generally seemed to like how they could coast and control regen with the Go pedal, but I think it would be more intuitive to coast when you take your foot off the Go pedal, and regen to occur when you touch the brake pedal. Additionally, I'd like to control the amount of regen via pressure on the brake pedal, until the point where the software figures out the friction pads need to get involved.

This would be a more efficient means of energy conversion than the "regen is always present and a fixed level" approach.

Can the current owners give their thoughts please? Thanks.

archibaldcrane | January 4, 2013

You can "turn down" the amount of regen that kicks in when you take your foot off the accelerator, but you can't "coast" like you could in a stick shift in neutral or with your clutch depressed. However, unlike an ICE, staying slightly on the accelerator to maintain speed doesn't mean you have to maintain your "RPM" and chew up gasoline in the process. Even the slightest touch of the accelerator (even if it's less than needed to maintain your speed, i.e. "coasting") will prevent your car from going into regen and slowing down - but you can't just take your foot completely off the pedal and coast.

GeekGirls | January 4, 2013

It took me a day or two to get used to but I absolutely love the "one foot" approach to driving. I've kept it on standard regen to give me as much control as possible and either I ease my foot back to the point where I am indeed coasting or I rely on the cruise control implementation which is absolutely wonderful. Much better than in the Lexus or Porsche that we own. Oh, it's also worth noting that the Model S regen is much smoother feeling than the Roadster implementation.

Switching to the brake means either I've misjudged my speed and need to change my habits, or someone else has done something I didn't anticipate. One oddity is the interaction between regen and creep: as far as I can tell, if creep is on then regen is disabled at a higher speed than when creep is off. It makes sense — until you hit the brake, and then regen should also kick in to slow the car but that doesn't appear to be the case. Not that it matters since I turned creep off after one day.

One question: why won't regen slow the car to a stop if creep is off? Does anyone know? Is this also the case in the Roadster? I've driven one a couple of times but I can't remember that particular detail.

Getting Amped Again | January 4, 2013

@archibaldcrane and @GeekGirls - thank you for your informative replies. It sounds like it's possible to coast, but the regen is constant based on which setting you select, "Standard" or "Low".

I guess ideally it would be nice if the first touch of the brake started a regen mode that was greater than your default setting, and then went to friction pads when you really tromped on it. That would get some regen created in the instances where you really need to slow down, but it's not a stop that results in you making mean faces at people. Right?

Mark2131@CA-US | January 4, 2013

Think of the regen settings as downshifting into 3rd gear or 2nd gear. Standard is like 2nd gear... it really grabs you when you let off the pedal. Great for the winding roads, steep hills etc. A bit too much for day to day traffic. "Low" is a lighter touch, kinda like the difference between 5th gear and 4 gear. You can feel it, but it's more subtle. This choice is better suited for bumper to bumper traffic.

Enjoy the "one pedal" experience!

dashrb | January 4, 2013

@Getting Amped Soon,

I've test driven the Model S but have not received mine yet.

The Model S has a nice display showing you the *amount* of regen you're generating. The 2006 prius has a more basic display which shows whether you're regen'ing or not (yes/no, but not a numeric amount). I recognize that the prius does *additional* regen if you subsequently apply the brake.

As a Prius owner, I have become used to the feeling of feathering the Go pedal to achieve coasting (the "no arrows mode" on the prius screen). It's muscle memory--difficult at first but become second nature over time.

With the model S's screen, you see a gauge showing the number of kW you are expending or regenerating. Feather the Go pedal to the "0" point, and you're coasting!

The regen isn't numerically "constant", though. In "standard" mode, it maxes out at a number which is twice as strong as the max in "Low" mode (I think it was 60 vs 30, but maybe 30 vs 15. I could be remembering incorrectly). But it's variable depending on environmental context (how fast are you going, temperature, etc) as well as how much are you pressing the Go pedal. Zero press of the Go pedal == maximum regen. Slight featuring would give you *some* regen. Heavier feathering would get you to 0 (coasting). Press harder still, and you are using energy (I would say "accelerating" but not technically necessarily (e.g. pointed uphill?)). To try to summarize, it's a scale of regen, and the dashboard display shows you how much or how little, in kW. You will stare at it as you attempt to perfect your right foot's muscle memory. Try not to run into anything.

Getting Amped Again | January 4, 2013

@dashrb - Thank you, I've got it now. The regen is variable, which is what I'd hoped for.

Optimum Range Driving

A) Coast as much as you can
B) Use friction brakes as rarely as possible
C) Use regen to make B) "truthier" (Thanks to Steven Colbert) | January 4, 2013

Driving at highway speeds this evening, and going slightly downhill, I observed the car was regenerating. This was while I had my foot lightly on the accelerator to maintain speed.

Brian H | January 4, 2013

In physics terms, "acceleration" is anything other than coasting. Faster, slower -- any application of energy to change speed or direction.

BTW, my term for the acceleration pedal is "goose pedal", as in "Goose it!". ☺ "Step on the goose!" ☻

Vawlkus | January 7, 2013

So you're "honking the goose" Brian? *wince*

rlpm | January 7, 2013

Honk honk! ;P