Despite you cutting and pasting together (out of context) "DC voltage source" and "installed in the same position as in the vehicle", these two statements actually come from different unrelated parts of the Regulation. There is no requirement for "DC voltage source to be installed in the same position as in the vehicle " anywhere in the Regulation, as DC voltage source is not provided by the manufacturer.
That's just not true. I've quoted nothing out of context.
This is from Annex 6: "
Method for measuring net power and the maximum30 minutes power of electric drive trains "
2.3.1. Auxiliaries to be fitted
During the test, the auxiliaries necessary for the drive train operation in theintended application (as listed in table 1 of this annex) shall be installed in thesame position as in the vehicle.
Item 1 of table 1 which the above sentence is referencing is "DC Voltage Source". Therefore it's to be installed in the same position as in the vehicle. Nothing you've referenced says it can be an arbitrary DC voltage source. If so, then you could fix that voltage source to provide enough current such that attaching electric accessories, which you do to measure how they impact the rated power, would be pointless.
Also, I never said that the the drivetrain could haven't multiple motors. I just said there's nothing in R85 that says you can add up the power from each motor into one number. Even where Tesla lists that they tested in accordance to R85, they don't sum up the motor powers. They are listed separately.
But, let's just assume that you're right in your interpretation, the following is still true:
- Tesla stated "691 hp motor power" on their website in multiple places. It did not state anywhere that "hp motor power" meant something other than hp produced by motors. There was no asterisk next to the horsepower spec stating that this is not actual horsepower produced by the production vehicle.
- The only place ECE R85 was referenced was inside the owners manuals and even these didn't contain the that reference until after the P85D was already shipping. Are we to expect that prospective buyers doing their research are supposed find this reference first in the owners manual?
- The subsystems page in the manual lists individual motor powers and does not add the front and rear motors together. In fact, if you add up front and rear motors, you get 728 hp, not 691 hp.
- Publications for over a year now have been publicizing 691 hp, not "hp motor power". Why hasn't tesla corrected them and why are they all still quoting 691 hp when the car only makes 480 to 555 hp depending on state of charge?
- The sales people repeatedly stated the P85D makes "691 horsepower" without ever adding the term "motor power".
- Elon Musk himself has been quoted as saying the P85D has 691 hp and did not use the term motor power. He's also been quoted as saying the P85D has 50% more power than the P85.
- If they were going to list a combined horsepower number, they had an obligation to list the power that the P85D actually makes. They do for the other Model S trims. In addition, since the P85D is the only Model S to lose power as the SOC declines in it's normal daily driving range, they should have clarified that the 555 hp is only at 90% SOC or greater and that below that, power will decline as charge declines. This is not true on the other Model S variants until you get much deeper in to charge state.
- Ignoring repeated multiple letters and emails over MONTHS asking for clarification about the horsepower rating. We get responses for everything else we ask but those that inquired about this got nothing. If they were being so above board about this with nothing to hide, how come they refused to respond to the question of "why is my car only making 480 to 555 hp (depending on SOC) when it was advertised at 691 hp"?
- Just because they test according to R85 to arrive at motor power ratings doesn't mean they get to use that in place of actual horsepower specified. Nowhere in the regulation does it state you can substitute horsepower rating of the vehicle with motor power capability of the drivetrain (with a power source not supplied). These are two entirely separate things. One is the actual horsepower produced by the vehicle. The other is an irrelevant specification that can't be reached with the shipping battery. It's only possible value would be knowing your drivetrain could handle more power if a battery with more power became available in the future.
Answer me these questions honestly:
Do you think the average consumer when they're looking up P85D specs and they see "691 hp motor power" will think it means something other than horsepower produced by the vehicle at some point?
What if they're relying on popular trustworthy consumer publications where they all say "691 hp" rather than "691 hp motor power"?
What if they're a P85 owner that knows their P85 makes "417 hp motor power" but it turns out that it really makes much more and such Tesla under promised and over delivered. Will this give them confidence that the P85D really makes the 691 advertised hp or should they expect to only get 555 hp, only some 80 hp more than the P85.
You keep saying Tesla was required to test with ECE R85. Well not in this country they weren't and even if they were in Europe, the drivetrain power rating is there for a legal listing requirement, not as an actual declaration of vehicle horsepower. They certainly weren't required to list "691 hp motor power" on their US website. Is there anything wrong with them testing with ECE R85 and listing drivetrain capacity? Not at all. But there is something seriously wrong with them trying to pass that off as horsepower produced by the vehicle(remember nowhere where 691 hp was stated did it say *tested in accordance with ECE R85 and that this is not the vehicle power actually produced in this configuration).
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Thanks for the detailed analysis. However, as others and I have stated before, the ECE R85 rating is basically equivalent to SAE Gross and is considered misleading in and of itself, regardless of whether the rating published by Tesla was correct or not. I'm sure you'll agree that it is not acceptable for an ICE manufacturer to rate their cars using SAE Gross today, because we realised some 40 years ago that SAE Gross is basically BS and decided to stop using it.
Actually, it's far far worse than that. SAE GROSS used prior to 1972:
SAE Gross Horsepower This is the old process that American manufacturers used as a guide for rating their cars. It was in place until 1971. SAE gross also measures horsepower at the flywheel, but with no accessories to bog it down. This is the bare engine with nothing but the absolute essentials attached to it; little more than a carb, fuel pump, oil pump, and water pump. Because the test equipment on the engine is not the same as in SAE net, it is impossible to provide a mathematical calculation between SAE net and SAE gross. As a general rule, however, SAE net tends to be approximately 80% of the value of SAE gross. SAE J245 and J1995 define this measurement.
And then in 19872:
SAE Net Horspower In 1972, American manufacturers phased in SAE net horsepower. This is the standard on which current American ratings are based. This rating is measured at the flywheel, on an engine dyno, but the engine is tested with all accessories installed, including a full exhaust system, all pumps, the alternator, the starter, and emissions controls. Both SAE net and SAE gross horsepower test procedures are documented in Society of Automotive Engineers standard J1349. Because SAE net is so common, this is the standard we will use to compare all others.
Since Tesla doesn't have mechanical accessories, drive belts, intakes, exhausts, and isn't effected by atmospheric pressure, temperature(mostly), and humidity, this standard doesn't apply.
However, without even reading through the rest of this thread yet, I'm willing to bet good money that someone will tell you that because these factors don't apply to EVs that there's no way to make an apples to apples comparison of an EV drive train to an ICE drivetrain. Of course that would be a bunch of nonsense. You can still measure horsepower of EV drivetrains but their output won't be restricted by most of the items listed in J1349.
Now the reason it's far far worse than you think is because tesla is not stating actual horsepower produced under any standard, not even under ECE R85. Instead, they are stating the combined horsepower capability of two drive units but only if you supplied 525 KW (691 hp) rather than the 414KW *actually supplied*.
Most of us who have an issue with this would have been *thrilled* if the P85D produced 691 hp at the battery before conversion losses and before drain from accessories.
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I know it is a fact that does not apparently fit your version of reality, but P85D was advertised as having 691 motor hp, rated by Tesla according to ECE R85, the only Regulation applicable to EV. This regulation directs manufacturers rate EV drive train without taking into account potential limitation of the propulsion battery. So if you put P85D drivetrain on a dyno and test in accordance to the protocol established in international Regulation ECE R85 it will produce exactly the hp it was advertised to produce.
You are playing loose with facts and *should apologize*.
But it doesn't direct them to lie about the actual horsepower produced.
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And there would be flying pigs if only pigs would fly.
Drum weight is the main problem here - it accumulates energy while speeding up. Heavier the drum, more energy it "eats" while speeding up for say 1%, lighter it gets, mores sensitive it will be as it will need less energy for same 1% change.
There were 'old' intertia-based with drums weighing in excess of 3000 pounds. Modern dynos are more sophisticated, using eddy current brakes etc but they still need to be strong enough to carry a 3000 pound vehicles. So they are still build of steel and have considerable dimensions and weight. And then there are also rotating parts in the car eating their part of that power burst.
I'd be glad if anyone can show me that there really exist some commercial dynos that can measure 10ms long 691HP burst at 50mph out of 550HP baseline. Joined hands in united "you are wrong" is no proof.
It all boils down to how long it has to output 691HP for one to be satisfied. 1ms, 1s, 1hour?
A 1 ms 691 hp burst through P85D's drivetrain would not measure on any dyno no matter how fast it sampled. The inertia the drive unit, reduction gear, diff, drive shafts, and wheels would absorb such a short burst and it wouldn't even be a blip.
But are really back to "prove the P85D doesn't make 691 hp"? Tesla has already admitted it doesn't which is why that debate died out over a month ago.
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I'll also provide another counter example about his "Installed in the same position as in vehicle" point. Look at #5 of the same table 1 "bench test auxiliary fan". That is a item that clearly does not exist in a production vehicle, but it also is included in the same table. Thus, "Installed in the same position as in vehicle" obviously does not apply to all items in the list, only to the items where it specifies it must be production equipment.
I think that's a pretty astute observation. But I take this as more evidence that this spec is just badly worded and probably full of errors. 2.3.1 says the items in table 1 are to be fitted as in the vehicle but clearly an auxiliary bench fan can't fall into that.
I spent 10 years writing software for manufacturing and automated testing devices and read through dozens of specs like this and there were always errors. What's worse is that when you asked the spec provider/author for clarification, they'd acknowledge the error, tell you how to interpret it, and then not actually rev the document.