Letter To Elon Musk Regarding P85D Horsepower – Discussion Thread

[vgrinshpun]

The reason R85 allows a power supply for the 30 minute continuous test, is simply because all current EVs would flatten their batteries at full power in under 30 minutes. It doesn't mean using an external power supply with a greater current capacity should be allowed IMHO.

As a clarification, ECE R85 allows an independent DC power supply for testing **both** NET POWER and the MAXIMUM 30 MINUTES POWER, as noted in Annex 6 of this regulation.

As for the reason for the specified duration for NET POWER and the MAXIMUM 30 MINUTES POWER, I do not believe it is due to limitations of the battery (this Regulation, after all, does not consider the battery limitations at all). The more likely reason, similar to sizing all motors, is driven by duty cycle, i.e. in this case application of the motor to the automotive propulsion system. The NET POWER is there to provide information about ability of car during short bursts of acceleration, while MAXIMUM 30 MINUTES POWER is intended to provide information on car's ability to sustain high speed driving.

The other examples of sizing motor to match expected duty is sizing motors for pumps and fans for continuous operation, as opposed to sizing motors for, say, elevators to sustain specific cycles of intermittent operation.

 

[lolachampcar]

It seems the thing that is causing the most irritation is that the above test results are not 100% indicative of the "car's ability" in the case of the PD as the battery is the weak link. It is not that Tesla was not conforming to the testing standard but that the testing standard for motors does not accurately reflect the car's ability given the natural battery limitations on high performance - long range BeVs.

 

[Alipapa]

Actually looking it up, restaurants typically give the precooked weight:

https://www.washingtonpost.com/life...f5e2b4-89c0-11e3-916e-e01534b1e132_story.html
http://forum.bodybuilding.com/showthread.php?t=5410503

The actual weight you get when the water is out of the steak is significantly lower:
http://www.ontheregimen.com/2013/08/28/how-to-weigh-meat-cooked-or-raw/

So this is actually an example that supports Tesla's case! I see it very similar to a lot of people here claiming that publishing horsepower based on a standard that is not system power is false advertisement, but they miss that fact that there is an existing industry standard (ECE R85) that is not system power (and I have been saying, for the ICE case, SAE gross also is not system power).

So you don't know what dry aged steak is?

 

[jkn]

What could MS do with 1.1 g and 700 hp:

Assuming total mass 2200 kg
First 1.1 g acceleration from 0 to 22 m/s (= 49.2 mph) in 2.038 s. (700 hp can give 1.1 g up to 49.2 mph)
Then acceleration with constant 700 hp from 49.2 mph to 60 mph in 0.497 s. ( t = m(v² - v0²)/2P )
Total 2.535 s -1 foot roll out = 2.296 s

So max acceleration is less than 1.1 g or power is less than 700 hp or I made a mistake.

Again with 1 g acceleration from 0 to 24.2 m/s (= 54.1 mph) in 2.466 s.
Then acceleration with constant 700 hp from 54.1 mph to 60 mph in 0.283 s.
total 2.749 s -1 foot roll out = 2.498 s

Time needed to floor the pedal should be added.

Perhaps 1.1 g will shift weight so that front motor cannot give full power below 49 mph. Center of mass needed for calculation.

 

[lolachampcar]

Just out of curiosity, did a letter get written? Was it signed by a large number of owners? Was there a response from Tesla? If so, what did they say in direct response to the letter?

 

[darthy001]

Just out of curiosity, did a letter get written? Was it signed by a large number of owners? Was there a response from Tesla? If so, what did they say in direct response to the letter?

Letter was written and sent by Andyw. Dont think a response of any kind has been given. Around 50owners signed I believe.

The first post in this thread should link to the actual letter text.

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It seems the thing that is causing the most irritation is that the above test results are not 100% indicative of the "car's ability" in the case of the PD as the battery is the weak link. It is not that Tesla was not conforming to the testing standard but that the testing standard for motors does not accurately reflect the car's ability given the natural battery limitations on high performance - long range BeVs.

Correct, and of course that Tesla introduced this new way of rating cars without giving any info about it. Topped of by directly claiming 700hp in Denmark without even adding "motor power"-wording at all.

For us europeans the whole sudden addition of rollout to only one model in the lineup is of course also causing much irritation as it made side by side comparison of stats on the ordering page not 1:1 as it made an artificially wide gap between the 85D and the P85D. Once again without any warning of changed methods how 0-100kph times was measured.

Might be that Tesla wont lose in court, outside of Denmark that is, but Teslas reluctance to post real HP-numbers for their two top-models says it all to me. They know they gave us the impression of 691/700hp, and now they are afraid to list the true number.

Strangely Tesla had no objection when the entire world press and even their own famous CEO said the car had 691/700hp. In other cases like the NY Times scandal, the fires etc etc they tried correcting the press instantly when they didnt state the correct stats or facts about the Model S. This is not the Tesla I started rooting for some years ago.

 

[Lump]

Owners Question Tesla P85D Power Output | News, Letter | Digital Trends

Tesla Model S owners claim P85D hp rating is exaggerated | LeftLaneNews
News has left TMC.

 

[Andyw2100]

Just out of curiosity, did a letter get written? Was it signed by a large number of owners? Was there a response from Tesla? If so, what did they say in direct response to the letter?

Letter was written and sent by Andyw. Dont think a response of any kind has been given. Around 50owners signed I believe.

darthy001 has it almost exactly correct.

The letter was sent, signed by a total of 71 people, most, but not all, of whom were owners. We have not received a direct response. (Some might suggest the blog post by JB Straubel was at least partially in response.)

This is what I wrote about it at the time:

The letter has been sent via Fed Ex, for delivery tomorrow morning, by 10:30 AM.

There were a total of 71 signers, made up mostly of P85D owners. We did have support from about ten other Tesla car owners, investors who do not own cars, and Tesla supporters.

As a group, we actually own a substantial amount of stock. After polling those signing, I wound up including the following line, along with the signatures:

"The signers of this letter together hold at least 13,523 shares of Tesla stock (self-reported.)"


I believe that is significant, as it demonstrates that we really are interested in Tesla's well-being, and not just our own.

Thanks again to everyone who signed, for everyone's support, and especially to wk057 and sorka for both their help with the letter, and their insightful posts that have helped so many of us understand the issue.

 

[lolachampcar]

Darthy,
And I thought the US was litigious. Man I hope we are not exporting that bad habit.
"Might be that Tesla wont lose in court, outside of Denmark that is,"

 

[darthy001]

Darthy,
And I thought the US was litigious. Man I hope we are not exporting that bad habit.
"Might be that Tesla wont lose in court, outside of Denmark that is,"

hehe good point I won't be doing any such thing myself, but I know that some people are considering it in both Norway and Denmark at the moment. But those people are going and have been going all other possible routes first. They have tried secret dialogue with Tesla, open dialogue with Tesla and going to the press in both countries. I believe they are no going via norwegian and danish consumer affairs-authorities as a last resort before legal action. So not straight to legal action as we would call "the american way" here

The public responses made by the nordic PR-rep from Tesla seems to just have fueled their anger since he openly accused them of "only being after a free ludicrous-upgrade".. Something that is quite ridiculous since they sent several formal letters to Tesla _before_ the ludicrous-upgrade was even officially announced... So instead of answering their questions 4-5months ago he now came out in september with lies and false accusations.

Edit: direct comment to you quote: reference to Denmark was about the advertising there being so obvious in terms of simply saying "700hp" that Tesla wouldn't stand a chance in court if anyone was to sue them over this in Denmark. I believe Tesla stands a good chance in Norway unless someone is able to find screenshots of the design studio from the weeks just after the D-event. Starting to need a tinfoil hat here since I cannot find a single screenshot of that for Norway, and I do believe it said 700hp in Norway as well. Believe me I have searched

 

[sorka]

I believe that Tesla legal department advised Tesla to limit dissemination of information for P85D because of the threat of the law suits coming from small but vocal group of owners. I personally do not like this situation, but it is just a reality of it.

------EDIT-----

If interested, you can read much more on this - see couple of pages following the linked post:

Tesla blog post: AWD Motor Power and Torque Specifications - Page 30

Or it could be that in all the other cases of currently available models the combined output listed is actually achieved or exceeded

 

[smac]

Or it could be that in all the other cases of currently available models the combined output listed is actually achieved or exceeded

No it's because the P90 ludicrous upgrade also ups the motor power under R85 to more than it had in P85D despite having the identical motors... obviously you* needed to studied more in physics classes


(* as did I)

 

[jpet]

No it's because the P90 ludicrous upgrade also ups the motor power under R85 to more than it had in P85D despite having the identical motors... obviously you* needed to studied more in physics classes


(* as did I)

I wonder why Tesla makes these changes without clarifying them. I guess this could avoid a lot of frustration.
Do we, as P85D owners, now all of a sudden have motors that can achieve even higher performance given the right battery / fuse / contactor combination or not?
Numbers require context to be correctly interpreted. IMO, it would be good for Tesla to provide more context.

One of the questions that keeps on spinning in my head is why the fuse was upgraded from 1300A to 1500A and not to 1613A?
Can the new electronic fuse be reprogrammed to blow at 1600A, 1700A, 2000A or is 1500A a fixed limit?
415 / 1300 * 1613 = 515 by the way :wink:

 

[vgrinshpun]

Or it could be that in all the other cases of currently available models the combined output listed is actually achieved or exceeded

Well, if you are implying that they did not show total output of the P85D because they wanted to keep the fact that it is limited by the capability of the battery a secret, the logic does not add up - Tesla detailed this in JB's Blog - the "secret" is out.
So we are back to the lawyers keeping Tesla from displaying this information on the ordering page

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I wonder why Tesla makes these changes without clarifying them. I guess this could avoid a lot of frustration.
Do we, as P85D owners, now all of a sudden have motors that can achieve even higher performance given the right battery / fuse / contactor combination or not?
Numbers require context to be correctly interpreted. IMO, it would be good for Tesla to provide more context.

One of the questions that keeps on spinning in my head is why the fuse was upgraded from 1300A to 1500A and not to 1613A?
Can the new electronic fuse be reprogrammed to blow at 1600A, 1700A, 2000A or is 1500A a fixed limit?
415 / 1300 * 1613 = 515 by the way :wink:

Tesla technically did not make changes, they added more information on the ordering page, except for P85D.

They did clarify/detail all of their horsepower ratings in Blog Post prepared by their Chief Technical Officer JB Straubel - a lot of context is there.

As to your question regarding the fuse, technically it did not change maximum electrical power rating of the battery, it just improved precision of system protection, which, in turn, allowed to lower the safety margin, puling more power from the battery with the same electric power rating. So additional electrical output from the battery which is part of Ludicrous is due to the fact that a better precision of the protection allowed Tesla to reduce safety margin without effecting the overall reliability.

And yes, provided a larger battery, or an improved power output of the same size battery, the current P85Ds can pack even more potent acceleration. Just to clarify, the 691hp was rated output of the drivetrain, i.e. it includs both the motor(s) and the power electronic modules (PEM)

 

[jpet]

They did clarify/detail all of their horsepower ratings in Blog Post prepared by their Chief Technical Officer JB Straubel - a lot of context is there.

When I ordered my P85D, the individual motor power advertised in Belgium was 221 hp front and 479 hp rear.
Now, the P85D is advertised as 262 hp front and 510 hp rear.

I did not find any info in the blog post or anywhere else as to this change. Isn't this strange / confusing? My guess is that the motors are the same but were re-rated but I can only guess. Suppose the motors are the same but were re-rated, isn't that a positive thing for existing owners that Tesla should put in the spotlight? Why not write a positive blog post about this to make P85D owners feel good about their choice?

The same goes for the max battery power. We all know that battery technology improves year over year. So there is a good chance that we will be able to upgrade our battery to e.g. a 110 kWh model in a couple of years. If the P85D already has motors on board that are rated significantly higher than the current 85 kWh battery can support, why not explain that this offers the option to improve the performance of the car when higher capacity batteries become available?

This type of positive context, if my assumptions are correct of course, could help counter the current negative vibe around the performance of the P85D.
When people are not offered enough background info / context, they start making things up and it is quite difficult to control this process. IMO, Tesla can benefit from being a bit more open about the numbers they quote and the changes they make. With changes I refer to staggered or not staggered setups, sport suspension or no sport suspension (sway bar thickness), choice of tires, next gen seats at the back or not, etc...

 

[stopcrazypp]

So you don't know what dry aged steak is?

Admittedly I don't really eat steak, but looking more closely at the nuances of your claim, I guess I got confused by the big gap in your numbers (1/3 loss in weight). However, the main point still pretty much remains after examining the details: the main issue is that the actual steak you get on your plate is significantly lighter than advertised because of water loss.

This is going to be very OT, but to address the nuances:
While a dry aged piece of meat will lose ~30% of its weight, the weight is lost in the parts that are inedible and are trimmed off in the first place. The actual weight density difference by the time the piece of meat is cut into a steak is 4-5%. That is why a dry aged steak and an unaged steak sold at a store has no visibly notable size difference for the same weight (not anywhere near 30%). And as relevant to the water loss during cooking, because the dry aged steak loses less water during cooking, that difference disappears after cooking.
http://www.seriouseats.com/2013/03/the-food-lab-complete-guide-to-dry-aging-beef-at-home.html

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No it's because the P90 ludicrous upgrade also ups the motor power under R85 to more than it had in P85D despite having the identical motors... obviously you* needed to studied more in physics classes


(* as did I)

I see this continual claim that it is somehow a physics violation for motor power numbers to change or that somehow changing numbers invalidates that it is a rating for the motor. However, you forget that the ECE R85 test and Tesla's rating includes the motor controller and inverter. Tesla did a software update to the motor controller with 6.2 that boosted the individual 188 hp motor power rating of the 85D to 259 hp. The numbers likely just carried over to the P85D.

And in all those tests, the voltage, rpm, and thermal limits are set by the manufacturer. If the manufacturer changes any of those parameters, it is possible to get higher numbers out of the same physical motor (even ignoring motor controller software updates). This stems from how ECE R85 is very much a gross power measure that gives the manufacturer a lot of leeway in setting parameters (similar to SAE gross). I imagine the SAE standard being drafted will be much stricter about this.

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Now Tesla is saying that at the same time that they were doing that, they were using a European standard--ECE R85--here in the US, and everywhere else to give the specifications for the power the car could produce. That's a standard that people in the US would have absolutely no reason to know anything about.

It seems to me Tesla can't have it both ways. It's completely disingenuous to cherry pick standards and practices from different parts of the world in order to make your car look as good as it possibly can. You could argue that the car is built in America, and thus was using American standards, and if the Europeans didn't know about 1-foot rollout, so be it. But you can't then follow up with, "Oh, and we used a European standard that Americans know nothing about to advertise the car's power capabilities in the United States and elsewhere."

Well, the thing is there is no American standard to use yet (SAE is working on it). And rather than them picking the European standard, I think they wanted to pick a standard that reflected the motor differences rather than the battery differences. It just happened that the European standard met that goal. Remember, the switch to motor power was made in regards to the dual motor launch (they previously had system power numbers when it was all single motor). It was not made in order to advertise the P85D specifically. I constantly mention this, but it is easy to forget. That is why I don't feel they set out to deceive, but rather as Straubel said they felt it better reflects the performance advantages of the dual motor.

 

[Stoneymonster]

Official model X specs on the website show *only* motor power figures.

 

[Matias]

One interesting fact. Matza had 9 hp (6%) less than advertised. What did they do? They bought the cars back, if owner wanted

"In the United States, Mazda erroneously quoted the power figure for the Japanese and Australian model in early catalogues. Car and Driver magazine and numerous owners confirmed the missing power, and Mazda offered to buy back the 2001 cars due to those misleading power claims. "

Mazda MX-5 - Wikipedia, the free encyclopedia

 

[LetsGoFast]

I believe that Tesla legal department advised Tesla to limit dissemination of information for P85D because of the threat of the law suits coming from small but vocal group of owners. I personally do not like this situation, but it is just a reality of it.

As best I can tell, Tesla limits "dissemination of information" about most every possible topic, threatened law suits or not.

 

[Laserbrain]

Matza had 9 hp (6%) less than advertised. What did they do? They bought the cars back, if owner wanted

This would be exactly the correct solution. Tesla should offer unhappy P85D customers who feel misled to buy their cars back.

And for Pete's sake they should put the combined HP for the P85D on their website like they do for the 70D and 90D.

And they should decide whether they measure their 0-60 acceleration with or without rollout, but really: ONE method for ALL models (preferably the scientific correct method, which means 0 mph is 0 mph and 60 mph is 60 mph, instead of this misleading rollout BS).

I know a small but vocal group of Tesla apologists tries to throw rhetoric smoke grenates on this topic, but this does not change the fact, that Tesla did mislead their customers (and are still misleading their customers!). It does not help to bury the topic in the legal department or to have some PR consultants have a go at it.

So will Tesla do something about it? No, of course not. It would cost money. Its like in the movie Fight Club:

A new car built by my company leaves somewhere traveling at 60 mph. The rear differential locks up. The car crashes and burns with everyone trapped inside. Now, should we initiate a recall? Take the number of vehicles in the field, A, multiply by the probable rate of failure, B, multiply by the average out-of-court settlement, C. A times B times C equals X. If X is less than the cost of a recall, we don't do one.

The only sad thing is, that I thought Tesla is different - an awesome company, because they built a new type of car, an electric car, an awseome car. But now I get to realize that they are just like every other company. This is just sad, because I really think they could be a better company.

Sorry for my rant.