That Motor Trend 1 foot rollout

[D.E.]

Wow, 1 foot roll out thread becomes a battery capacity debate

1 foot rollout is simple, based on timing lights and is approximately how far the tire needs to roll, because it is round, to trip timing lights that are mounted at ground level. Pretty clear reference here - http://www.caranddriver.com/features/the-importance-of-rollout

That is a rationalization of a one foot rollout used in a 1/4 mile timed run at a drag strip. That may be valid. It is not valid to omit the first foot of travel in a timed 0-60 measurement.

There are some fundamental differences in what is being measured. One should not assume that if it is OK for the 1/4 mile then it is OK to use it in all other measurements.

The P100DL is amazingly quick. It will reach 60 in a few car lengths.

Consumer Reports and Edmunds have done testing on some Teslas without introducing that error from not including the first foot of travel in the measurement.

When you give a car the first foot of travel before starting the clock, that is the slowest foot of travel. It makes much more of a difference to the run time than if it were an average foot of travel or an end of run foot of travel.

Anyway, the rollout is probably OK for 1/4 mile timed events but it is not fine for the 0-60 measurements. It introduces a huge error. Failing to recognize that error is the crux of this thread.

 

[stopcrazypp]

I see, so it's "denial" - those people who got the 81 number from Tesla's own diagnostics just happen to get defective cars (in case of wk057 he got more than one identically defective 81KWhr battery). As for rounding up to the nearest 5k, funny how they wouldn't round up my check to the nearest 5k.

PS) I'm looking forward towards your interpretation of "Full Self Driving" , "ride hailing", " car sharing", "summon anywhere on the property" and other Tesla FSD AP2 promises in a couple of years.

The numbers are pulled from cars with various amounts of cycling and calendar aging on it and based on average power demand (as noted above given a power demand equivalent to the EPA UDDS cycle, it's possible to pull more). Tesla's diagnostics system (unlike something like Nissan's) does not provide a baseline number from factory. You can only pull what is the pack's current best guess at the capacity, not what it was from the factory.

I will have to dig up the exact numbers, but this type of cell can lose 2-3% of capacity within the first couple of cycles. So the variation that is seen in the rated miles numbers (people getting 270 miles) can be a part of this.

But anyways, Tesla is moving away from kWh as a model designation exactly to avoid the hand-wringing over the exact numbers.

 

[Laserbrain]

The 1ft rollout has always been bullshit and it will always be bullshit.

When you use it, you simply do not measure the 0-60 time. And here I have to quote Spicer (even though this might make my argument look weak): "Period!" Really. Either you measure 0-60 or some bullshit. 1 ft rollout is bullshit. End of discussion.

Unless of course you are one of these people who considers science as devil's work and you would like to ban science and things like evolution theory from the school curriculum.

Well, do as you please, but the rollout scam has always been a rollout scam.

BUT, to keep the perspective: the rollout scam is not as bad as diesel gate. The rollout scam did not kill people for profit like the diesel gate (what some non-banana republics would call murder).

I am just getting salty when someone is pissing on science itself. 0-60 with rollout is not 0-60.

 

[whitex]

But anyways, Tesla is moving away from kWh as a model designation exactly to avoid the hand-wringing over the exact numbers.

It wasn't model designation I had a problem with, it was the battery spec. Here is the difference:

Whether they are moving away from it with Model 3 or not doesn't affect the Model S's & X's they sold already (and are still selling). How coincidental btw that everyone who ever go into the diagnostics software got the same degradation (wk057, ingineer, etc).

 

[McRat]

Name the brand of car:

"Times Based On Initial Movement"
"Horsepower per SAE J2723"
"Take your production car to a track day and you have an issue with one of your parts, it's covered under warranty"

 

[stopcrazypp]

It wasn't model designation I had a problem with, it was the battery spec. Here is the difference:
View attachment 243165

It's the model designation for the pack. Not a whole lot different from Mercedes calling their 6.208 L engine the "6.3" (not the the "63 AMG" car model badge without the decimal, but separate badge that says "6.3").

Whether they are moving away from it with Model 3 or not doesn't affect the Model S's & X's they sold already (and are still selling). How coincidental btw that everyone who ever go into the diagnostics software got the same degradation (wk057, ingineer, etc).

I don't believe ingineer ever posted his measurements for the 85kWh pack (link please if you have it). Only that he found the same inconsistencies on how Tesla does the rounding. It's too late now to see results if they haven't been recorded as the aging would be even more.

 

[vgrinshpun]

The numbers are pulled from cars with various amounts of cycling and calendar aging on it and based on average power demand (as noted above given a power demand equivalent to the EPA UDDS cycle, it's possible to pull more). Tesla's diagnostics system (unlike something like Nissan's) does not provide a baseline number from factory. You can only pull what is the pack's current best guess at the capacity, not what it was from the factory.

I will have to dig up the exact numbers, but this type of cell can lose 2-3% of capacity within the first couple of cycles. So the variation that is seen in the rated miles numbers (people getting 270 miles) can be a part of this.

But anyways, Tesla is moving away from kWh as a model designation exactly to avoid the hand-wringing over the exact numbers.

My car's 100% charge was 272 miles when new.

 

[vgrinshpun]

It wasn't model designation I had a problem with, it was the battery spec. Here is the difference:
View attachment 243165

Whether they are moving away from it with Model 3 or not doesn't affect the Model S's & X's they sold already (and are still selling). How coincidental btw that everyone who ever go into the diagnostics software got the same degradation (wk057, ingineer, etc).

wk057 never provided detailed information on **which** internal parameters he used to arrive at his "up to 81kWh, 77kWh usable" claim. There are several parameters available from the can bus data:

• Nominal Full Pack Energy
• Nominal Energy Remaining
• Expected Energy Remaining
• Ideal Energy Remaining

I do not believe anybody outside Tesla knows what is the precise definition for each of these parameters.

The actual can bus data shared by @Dennis87 a while ago indicated that for a 85D battery "Ideal Energy of the pack" = "Ideal Energy Remaining" + "Energy Buffer" = 80.1 kWh + 4 kWh = 84.1 kWh

This is not consistent with the "up to 81 kWh, 77 kWh usable claim".

 

[vgrinshpun]

The 1ft rollout has always been bullshit and it will always be bullshit.

When you use it, you simply do not measure the 0-60 time. And here I have to quote Spicer (even though this might make my argument look weak): "Period!" Really. Either you measure 0-60 or some bullshit. 1 ft rollout is bullshit. End of discussion.

Unless of course you are one of these people who considers science as devil's work and you would like to ban science and things like evolution theory from the school curriculum.

Well, do as you please, but the rollout scam has always been a rollout scam.

BUT, to keep the perspective: the rollout scam is not as bad as diesel gate. The rollout scam did not kill people for profit like the diesel gate (what some non-banana republics would call murder).

I am just getting salty when someone is pissing on science itself. 0-60 with rollout is not 0-60.

I suggest to cross post this to the BMW US Internet discussion forum: Bimmerfest.com.

 

[stopcrazypp]

wk057 never provided detailed information on **which** internal parameters he used to arrive at his "up to 81kWh, 77kWh usable" claim. There are several parameters available from the can bus data:

• Nominal Full Pack Energy
• Nominal Energy Remaining
• Expected Energy Remaining
• Ideal Energy Remaining

I do not believe anybody outside Tesla knows what is the precise definition for each of these parameters.

The actual can bus data shared by @Dennis87 a while ago indicated that for a 85D battery "Ideal Energy of the pack" = "Ideal Energy Remaining" + "Energy Buffer" = 80.1 kWh + 4 kWh = 84.1 kWh

This is not consistent with the "up to 81 kWh, 77 kWh usable claim".

View attachment 243183

Thanks for pointing this out. This is exactly what I was talking about. It's not that all samples are the same. There are some that are higher, some lower. This is to be expected given the number is not a consistent number set by factory.

It'll be different if Tesla used a baseline number and then have a modifier for degradation (similar to the Nissan battery wear bar), but that's not how Tesla's system works.

 

[DarkMatter]

A quick and above all else, relatively inexpensive solution to making something or someone go away, is often times a quite favorable option.

I think you're agreeing with me. The lawsuit being settled quickly means it was mutually beneficial, certainly. It doesn't typically imply much about the actual merit of the case.

 

[AnxietyRanger]

It's the model designation for the pack. Not a whole lot different from Mercedes calling their 6.208 L engine the "6.3" (not the the "63 AMG" car model badge without the decimal, but separate badge that says "6.3").

The thing is, Mercedes gives the actual engine displacement in the specs, even if they call it the 6.3 as a shorthand.

Had Tesla said the 85 had an 81 kWh battery in the specs, they'd be on par with Mercedes.

They did not. The closest to specs Tesla gave said 85 kWh.

 

[P85DEE]

I think you're agreeing with me. The lawsuit being settled quickly means it was mutually beneficial, certainly. It doesn't typically imply much about the actual merit of the case.

"Mutually beneficial", is a bit misleading in that yes, each party will receive some measure of "benefit" in a quick settlement.

But is the "quick settlement" fair and equitable to both parties as a result of having been "quick"?

A "quick settlement" may work to the benefit of one party, but not necessarily to the equal benefit of the other.

If someone were to crash into you, and you sustained significant injury in the crash, and you were not at fault, well then a "quick settlement", may be of some benefit to you.

But if it calls for monetary damages significantly less than what would be commensurate with your degree of injury, then how much net benefit would you end up with when offset against the prior benefit of the settlement having been "quick"?

If someone commits a deliberate wrong, which Tesla was accused of in the Norway case, and a "quick settlement" results in those injured as a result of the wrong, getting about "half" of what they asked for, and furthermore still not getting the horsepower that they say that was sold to them, well then again that "quick settlement", may or may not be commensurate with their degree of claimed loss as a result of Tesla's acts.

When the price difference, certain performance aspect differences, and the measured (SAE) horsepower difference, between the 85D vs the P85D are considered by some of those observing the position that Tesla had engaged in deceit in this matter, it appears that Tesla came out much further ahead in this legal matter than those 126 plaintiffs did.


As to your point about the "actual merit of the case", OK.

The "merit" of the case, or lack thereof, has already been hotly debated and beaten to death.

But at the end of the day, and from a practical standpoint, what does it matter if a plaintiff goes into a legal proceeding with a case that he thinks has all the "merit" in the world, if he comes out with monetary damages which aren't commensurate with his degree of injury?

Unless he's counting "moral victories".

In that situation, it works more to the benefit of the defendant than it does to the benefit of the plaintiff.

Tesla settling this matter in the way that they did, and for the amount of money spent, appears to have been a definite win for them.

On the flip side, considering the eventual monetary compensation that the 126 plaintiffs ultimately "won" in their legal proceedings and claim as to what was done to them, well only each of that 126 can ultimately decide as to if it was "fair" compensation.

But to this observer, and no doubt others, taking into account what was being alleged, ......either way, whether it was because the settlement was "quick", or whether it was because the case didn't have as much "merit" as some thought, ... they didn't get much.

 

[vgrinshpun]

The thing is, Mercedes gives the actual engine displacement in the specs, even if they call it the 6.3 as a shorthand.

Had Tesla said the 85 had an 81 kWh battery in the specs, they'd be on par with Mercedes.

They did not. The closest to specs Tesla gave said 85 kWh.

Well, you are missing point about variability of the battery capacity. It is so variable under normal day to day changing parameters that it is meaningless to publish it, especially when non-professionals descend and start rendering verdicts without real basis. For example, just taking into consideration one parameter, temperature, minimum capacity of my battery during winter is about 1kWh less than maximum one during summer, as expressed by the range at 90% charge (3+ miles of range difference).

The engine displacement is also variable, but much les so than battery capacity. It is imperceptible under normal day to day variations in parameters.

As for the validity of 85kWh given by Tesla, as seen from the posts above, it seem legitimate to me, notwithstanding the usual hysteria whipped by the Internets.

 

[D.E.]

Motor Trend says a P100D is moving 5.9 MPH when they start their 0-60 clock.
https://www.motortrend.com/news/a-c...esla-model-s-p100d-ludicrous-acceleration-run

So their measurement is the time from 5.9 MPH to 60 MPH, or an acceleration of 54.1 MPH. That first foot takes 0.26 seconds. They report their measured time to 60 MPH as 2.28 seconds. So the true 0-60 time using their measurements of 0.26 seconds for the first foot plus the measured 2.28 seconds is a corrected time of 2.54 seconds for the standstill to 60 MPH. The error is 10.2%. 2.54 seconds is still wickedly fast, but it isn’t 2.28 seconds.

A 1 foot rollout in a 1/4 mile run is 1 part in 1320 or 0.075%

Motor Trend’s position is that since a 1 foot rollout doesn’t appreciably affect 1/4 mile times, then it is also valid for other measurements such as 0-60 times as well. The flaw is that the error for the P100D with the rollout is 136 times higher than if the rollout is included in a quarter mile measurement.

Some people claim that since the 1 foot rollout is now “standard”, that people would not be able to compare 0-60 times if measured without the rollout. Since the error is not constant but is proportional to the acceleration, comparison of times are not accurate. You can say one car is faster than another but you cannot simply look at the times and tell exactly how much faster one car is than the other.

Then clickbait sites such as Top Gear compare old recorded times and pretend to have run drag races, reporting their comparisons as real race results. They are not. The old times they use don’t account for differences in track temperatures, air density, wind, and in Tesla’s case, battery charge, battery temperature, launch mode, etc. A real race is a race. A made up race is a fiction.

I’d like to see honesty across the board.

 

[Asterix187]

1 foot roll out is just cheating.

 

[faughtz]

1 foot roll out is just cheating.

Especially when it’s use is not acknowledged in order to sell cars (i.e 2014 P85D)

 

[sorka]

Motor Trend says a P100D is moving 5.9 MPH when they start their 0-60 clock.
A Closer Look at the 2017 Tesla Model S P100D's Ludicrous Acceleration Run - Motor Trend

So their measurement is the time from 5.9 MPH to 60 MPH, or an acceleration of 54.1 MPH. That first foot takes 0.26 seconds. They report their measured time to 60 MPH as 2.28 seconds. So the true 0-60 time using their measurements of 0.26 seconds for the first foot plus the measured 2.28 seconds is a corrected time of 2.54 seconds for the standstill to 60 MPH. The error is 10.2%. 2.54 seconds is still wickedly fast, but it isn’t 2.28 seconds.

A 1 foot rollout in a 1/4 mile run is 1 part in 1320 or 0.075%

Motor Trend’s position is that since a 1 foot rollout doesn’t appreciably affect 1/4 mile times, then it is also valid for other measurements such as 0-60 times as well. The flaw is that the error for the P100D with the rollout is 136 times higher than if the rollout is included in a quarter mile measurement.

Some people claim that since the 1 foot rollout is now “standard”, that people would not be able to compare 0-60 times if measured without the rollout. Since the error is not constant but is proportional to the acceleration, comparison of times are not accurate. You can say one car is faster than another but you cannot simply look at the times and tell exactly how much faster one car is than the other.

Then clickbait sites such as Top Gear compare old recorded times and pretend to have run drag races, reporting their comparisons as real race results. They are not. The old times they use don’t account for differences in track temperatures, air density, wind, and in Tesla’s case, battery charge, battery temperature, launch mode, etc. A real race is a race. A made up race is a fiction.

I’d like to see honesty across the board.

It IS standard in the US so if Tesla wants to compare apples to apples they have to use the 1ft rollout too.

It's a shame that is the standard because it makes Tesla look less impressive compared to other cars than if the standard was from 0.

Why? Because Tesla performance models kill all ice competitors by an even wider margin in the first foot.

You can't say Tesla is cheating if all other US manufacturers use the same cheat.

 

[whitex]

You can't say Tesla is cheating if all other US manufacturers use the same cheat.

Yes you can it is cheating if a manufacturer puts numbers without rollout and numbers with rollout into the same comparison table to make their performance cars look better. That is what Tesla did with P85D (and then later told us they "forgot" to add add an asterisk that only P cars were tested with rollout). They couldn't even use the BS excuse they tried with the power numbers, claiming that 463hp in an EV counts as 691hp, because the 0-60 times they were comparing were all Tesla EV's. A non-cheating way is to use the same measurement method when comparing specs, which is what other manufactures do.

 

[Big Toys]

"Roll-out"

(Correct me please if I misunderstand.)

From a physics standpoint, this makes no sense, since 0-60 measures final velocity over time, not distance. Second, at speed, your tires are now larger than at the start due to centrifugal forces, so you actually travel more distance with every revolution, but who cares, because we are measuring final speed/time, not distance. Third, your final speed/time is all dependent on your rate of distance change thru time (squared), so discounting the first foot of travel means you must discount the acceleration thru that distance, which could be a little, or could be a lot, since acceleration may not be purely exponential thru time. IOW, the 1 foot roll-out sounds like a bunch of gear heads decided to fudge what they could not compute. "The way we've always done it" is never good reasoning to do something.

As an educational aside, if the point of staging (start) is at the front base of the tire, what trips the clock to stop at the end of the drag track, the same front base of tire? I ask because the tire is now measurably, sometimes visibly bigger than at the start.