P85D motor hp controversy starts also to show in U.S. media

[cynix]

So it's my fault that I didn't do the proper research?

You're 100% right. I did not do enough proper research; therefore I am in error. I, personally, am responsible--not Tesla's marketing. I'm not going to blame Tesla--and every single other car manufacturer in the world--for advertising a $7500 tax credit that I can never obtain, though, even though there's no physical way I can obtain that level of depositing performance as advertised in real-world conditions.

Hey, this seems eerily similar to another topic at hand that we're discussing...

Tesla advertises the price of the car both with and without the tax credit. If they similarly advertised the power rating of the car both with and without the battery limitations then I think a lot of people here would have been satisfied.

 

[SDRick]

Tesla advertises the price of the car both with and without the tax credit. If they similarly advertised the power rating of the car both with and without the battery limitations then I think a lot of people here would have been satisfied.

Yes, and just think of all the negative energy and aggravation that would have been avoided along with the hundreds of pages of ink dedicated to this topic..

 

[gavinwang]

The major distinction between this analogy and the P85D power ratings is that while screen resolution uniquely defines characteristic which people pay money for, the total output including limitation of the battery (550hp) is *NOT* what defines the major selling point of P85D - 0.8s improvement in 0 to 60mph acceleration. This 0 to 60 acceleration, which is essentially what Tesla is selling in P85D and what it is charging the premium over 85D for, is absolutely defined by the motor hp per ECE R85, i.e. 691hp, *NOT* by the battery limit defined throughput of 550hp.

This is the major point which is very hard to grasp for anybody without technical (as in electrical engineering) background. All of the analogies I saw so far are really not valid. Essentially, the reason so many try to come with analogies (which are invariably wrong) is an indication of the fact that there is a lack of understanding and appreciation of the differences between EV and ICE based propulsion systems. I am hoping to carve time to demonstrate this clearly for anybody willing to give it a thought with an open mind, even without technical background.

The above reason for this analogy being flawed is a major, but not the only one. The second one is that while screen resolution is a fixed number, the battery power limitation is not. While a lot of people mention ambient temperature, state of charge and age of the battery, few if any realize that battery power output also depends on prior loading profile.

I've have mentioned these points before, but I believe very few people involved in this conversation understand/appreciate them.

We don't really need an analogy, just use common sense. Again, battery state causing the real output to vary is not the defense for advertising an output that the battery will never allow to happen. If you have a bucket with one short stave, you should tell people how much water that short stave allows the bucket to contain; you are free to ALSO tell people the hypothetical capacity of the bucket if there wasn't a short stave.

 

[stopcrazypp]

No, most people do know what the "i" means in 1080i, because there is usually a "1080p" next to it. I agree even ICE only advertises shaft power not wheel power, and loss can be non-negligible from shaft to wheels; however shaft power is at the least an output the car can put out at some point of the car in real life, whereas 691 on P85D is a thing the car can never produce at ANY part of the car, which means it's never real and never useful in real life. What if the battery was so bad and could only support 300HP peak output, instead of 550? Would you still find slamming 691 on the ad as the only number acceptable?

My point was that whereas the screen resolution represents what you see as an end user, the HP number quoted doesn't. For example, while the P85D loses 10% of its power by the time it reaches the wheels, a typical AWD ICE car is assumed at 35% loss.

Of course, having both a battery (or system) and motor number is the most ideal.

But I find the 691hp number acceptable because I knew what it meant and what it didn't. In practical terms, it tells me if I do a battery upgrade in the future, that is what the motors/inverters can support. I can see why however for people that assumed it meant a system power number and are of the opinion that all car manufacturers are required to advertise a system power number would find that unacceptable.

For a better part of a century, ICE car manufacturers have been advertising a number that the car can never produce in ANY part of the car and people found that acceptable also, given they knew that was the case. And in that case, it was even a number they can't legally get (requires running the car without a cat).

Also, knowing the individual numbers in the dual motor case is useful because the battery can output enough to support one at a time, while a combined system number would not reflect that. For example, an EV with a 300 hp battery and 300 hp front and rear motors adding to 600hp will perform better than one with 150 hp front and rear motors adding to 300hp, even though under a conventional rating, they would be the same number. I think this was the same motivation for Tesla (why they introduced it with the dual motors).

 

[WarpedOne]

Of course, having both a battery (or system) and motor number is the most ideal.

No. Ideal is max acceleration curve with speed on X axis and known tested weight.
This is what I sense with my butt dyno when I go drive the car. And this curves tell everything about the car performance - max speed and acceleration strength at any speed below max. One can deduce acceleration time between any speed points.
1/4 time is a 'first degree derivative' of such chart. It tells a lot about cars performance, but it does not say anything about low/high speed acceleration strenght.

*Everything* else is only partial information with innumerable hidden factors that will affect performance I will get.
HP number is meaningless, people are just used to it and blindly believe it. But it doesn't say anything about performance really.

Lotus Elise is one of the best sports car out there. It has mere ~250HP. There are +400HP cars out there that handle like dead cows and waaaay worse than that humble else.
Not to mention cars like Ariel Atom with 180HP and insane acceleration.

In short: stop talking about power, HP, torque and similar B*llSh*t. Give me acceleration curve. Then I will know everything that is to know about some car performance except for transient factors (overheating...).

 

[Luclyluciano]

No. Ideal is max acceleration curve with speed on X axis and known tested weight.
This is what I sense with my butt dyno when I go drive the car. And this curves tell everything about the car performance - max speed and acceleration strength at any speed below max. One can deduce acceleration time between any speed points.
1/4 time is a 'first degree derivative' of such chart. It tells a lot about cars performance, but it does not say anything about low/high speed acceleration strenght.

*Everything* else is only partial information with innumerable hidden factors that will affect performance I will get.
HP number is meaningless, people are just used to it and blindly believe it. But it doesn't say anything about performance really.

Lotus Elise is one of the best sports car out there. It has mere ~250HP. There are +400HP cars out there that handle like dead cows and waaaay worse than that humble else.
Not to mention cars like Ariel Atom with 180HP and insane acceleration.

In short: stop talking about power, HP, torque and similar B*llSh*t. Give me acceleration curve. Then I will know everything that is to know about some car performance except for transient factors (overheating...).

Its fine that the you believe the HP rating of the Tesla is meaningless to Tesla buyers, even if it's not true but many of us understand what it means and don't need a graph to understand this performance on the Tesla should mean. Most of us know the difference between a Lotus and a Tesla and we are not comparing handling so no need for a strawman. Plus, 0-60 is not the only performance measurement.

Lets say the Lotus with the true output of 250 HP was advertised and promoted by salespeople as having 325 HP output and you bought the car believing this and you paid a premium for this belief. Would there be a difference then.

Most of what I have seen in this thread is nothing but strawman arguments. Perhaps from many who did not spend the extra dollars to buy the PD so they have no skin in the game. Bottom line the car as is, does not output the HP many were led to believe. As is, it never has and never will.

Now with all the real info out, it is obvious the car is quick off the line but it is not fast.

 

[sorka]

No. Ideal is max acceleration curve with speed on X axis and known tested weight.
This is what I sense with my butt dyno when I go drive the car. And this curves tell everything about the car performance - max speed and acceleration strength at any speed below max. One can deduce acceleration time between any speed points.
1/4 time is a 'first degree derivative' of such chart. It tells a lot about cars performance, but it does not say anything about low/high speed acceleration strenght.

*Everything* else is only partial information with innumerable hidden factors that will affect performance I will get.
HP number is meaningless, people are just used to it and blindly believe it. But it doesn't say anything about performance really.

Lotus Elise is one of the best sports car out there. It has mere ~250HP. There are +400HP cars out there that handle like dead cows and waaaay worse than that humble else.
Not to mention cars like Ariel Atom with 180HP and insane acceleration.

In short: stop talking about power, HP, torque and similar B*llSh*t. Give me acceleration curve. Then I will know everything that is to know about some car performance except for transient factors (overheating...).

We obviously have very different butt dynos

 

[ERP]

Lotus Elise is one of the best sports car out there. It has mere ~250HP. There are +400HP cars out there that handle like dead cows and waaaay worse than that humble else.

The S2 Elise only has 190 hp stock, and even less torque. Its the supercharged versions which produce mid 200's at the crank. And despite the car's decent handling, that low horsepower is very apparent on any track with a few long straight sections. If it is not a tight track, a 400+ hp cow can put down better lap times.

For those interested, the stock Elise does not handle that well. To make the car safer for poor quality drivers, it was setup to understeer significantly from the factory. The car needs more front camber, wider wheels and R compound tires. The stock stocks/springs are also rubbish. But fix these issue and the car will hold 1.5 lateral g's and is truly a dream to drive. Then add the BOE Rev kit and bring power up to 300-400 hp and you have achieved driving nirvana.

 

[AmpedRealtor]

This is the major point which is very hard to grasp for anybody without technical (as in electrical engineering) background.

So maybe Tesla should present specifications that don't require a degree in electrical engineering to understand? Just thinking out loud.

 

[jpet]

Give me acceleration curve. Then I will know everything that is to know about some car performance except for transient factors (overheating...).

I agree, it would be awesome if Tesla could provide these curves for each model so that we can finally start comparing a 85D to a P85D, P85D, P90D, P90D...
This way we could also compare these curves to the curves of ICEs (which have a significantly different form).
To come back to the media topic of this thread, if Tesla does not provide us these acceleration curves, car magazines or consumer organizations could do these tests in a stable environment and be of significant help to us, buyers.

As you are also indicating, the curve alone is not enough because I regularly see the yellow power limiter appearing in my P85D. It does not require more than a couple of minutes to get it limited to 240 kW. But you won't get it if you just launch the car. Try driving it at 100 mph for a couple of minutes and then do a kick down... Of course, being able to drive at these speeds is not the most important thing in the world.

Knowing the strengths and weaknesses of the car is relevant info for someone interested in buying a Tesla. No vendor will be eager to give info on its weaknesses and that's probably why we're having the P85D motor hp controversy discussion.

 

[whitex]

So maybe Tesla should present specifications that don't require a degree in electrical engineering to understand? Just thinking out loud.

It's not that hard - the motors are capable of 691hp but the battery doesn't have enough juice to let them produce more than 550hp in ideal conditions. The car can go 50,000 miles on a single charge, but the battery will run out of charge in 200-300miles, depending on driving conditions. No electrical engineering degree required to understand.

 

[yak-55]

...the total output including limitation of the battery (550hp) is *NOT* what defines the major selling point of P85D - 0.8s improvement in 0 to 60mph acceleration. This 0 to 60 acceleration, which is essentially what Tesla is selling in P85D and what it is charging the premium over 85D for, is absolutely defined by the motor hp per ECE R85, i.e. 691hp, *NOT* by the battery limit defined throughput of 550hp.

Uh, no. No one upgrading from 85D to P85D is knowingly paying for the difference in claimed motor power as you understand it. Why would anyone pay such a premium for a specification difference they can never experience ?! Tesla is "selling" a lay interpretation of hp with a technical excuse. If they weren't selling hp and as you assert were only selling 0-60 acceleration, they would simply remove *all* the references to hp, or motor hp from their promotional materials. Unlike you, Tesla understands that "horsepower sells" and they are misrepresenting the real world difference in models precisely because they understand that.

 

[stopcrazypp]

Uh, no. No one upgrading from 85D to P85D is knowingly paying for the difference in claimed motor power as you understand it. Why would anyone pay such a premium for a specification difference they can never experience ?! Tesla is "selling" a lay interpretation of hp with a technical excuse. If they weren't selling hp and as you assert were only selling 0-60 acceleration, they would simply remove *all* the references to hp, or motor hp from their promotional materials. Unlike you, Tesla understands that "horsepower sells" and they are misrepresenting the real world difference in models precisely because they understand that.

The difference between the two models is Tesla is selling a car with a bigger motor in the rear that is capable of more power, even though the battery limits it overall. And in practical terms what happens is when there is more power demand on the rear wheels, the P85D can put out more than the 85D. That is precisely what the motor power number (as well as the individual numbers) was intended to convey. Also, P85D has more room for additional power after battery upgrades (for example Ludicrous retrofit), whereas 85D is already maxed out.

And if we move away from the focus on the P85D vs 85D, you can see how it applies to the other models:
S60 and S85 was rated the same motor power, showing they used the same motor/inverter.
S60D and S85D was rated the same motor power, showing they used the same motors/inverters.

 

[yak-55]

The difference between the two models is Tesla is selling a car with a bigger motor in the rear that is capable of more power, even though the battery limits it overall. And in practical terms what happens is when there is more power demand on the rear wheels, the P85D can put out more than the 85D. That is precisely what the motor power number (as well as the individual numbers) was intended to convey.

In the car, when there is high power demand, the P85D motors can put out about 50hp more than the 85D motors. That is precisely the reality that is deceptively avoided by Tesla's references to motor power. The significant price premium between models is much easier to sell when the power differential between models is represented as being much larger than it is.

 

[Andyw2100]

In the car, when there is high power demand, the P85D motors can put out about 50hp more than the 85D motors. That is precisely the reality that is deceptively avoided by Tesla's references to motor power. The significant price premium between models is much easier to sell when the power differential between models is represented as being much larger than it is.

And only at high SOCs. The difference in HP decreases as the SOC falls, and if I recall sorka's numbers correctly, at 60% SOC or lower, there is no difference in HP between the 85D and the P85D.

 

[SDRick]

And only at high SOCs. The difference in HP decreases as the SOC falls, and if I recall Sorka's numbers correctly, at 60% SOC or lower, there is no difference in HP between the 85D and the P85D.

Ouch!

 

[sorka]

The difference between the two models is Tesla is selling a car with a bigger motor in the rear that is capable of more power, even though the battery limits it overall. And in practical terms what happens is when there is more power demand on the rear wheels, the P85D can put out more than the 85D. That is precisely what the motor power number (as well as the individual numbers) was intended to convey. Also, P85D has more room for additional power after battery upgrades (for example Ludicrous retrofit), whereas 85D is already maxed out..

The difference is that the P85D was advertised with 315 more horsepower than the 85D when in reality it only has only up to 52 more horsepower(with no difference with both cars at 60% SOC). We didn't purchase the "room" for additional power with future battery upgrades which we'd *also* have to purchase. We purchased a car that was advertised with 691 hp as delivered.

- - - Updated - - -

WHAT!

Peak power at lower SOCs. The P85D still puts out more power at lower RPMs (more torque) than the 85D at any SOC(where both cars have the same SOC). This means the P85D will still kill the 85D from 0-60 at 60% but there won't be any difference in a roll on from 60 MPH on the freeway.

- - - Updated - - -

Strange, reply to message 558 is in message 557.

- - - Updated - - -

And now message 558 has been removed.

 

[Super_Popular]

I deleted my post because you explained your earlier response. You were just to quick.

 

[stopcrazypp]

In the car, when there is high power demand, the P85D motors can put out about 50hp more than the 85D motors. That is precisely the reality that is deceptively avoided by Tesla's references to motor power. The significant price premium between models is much easier to sell when the power differential between models is represented as being much larger than it is.

Yes, if the front motor was running at max power, the P85D as a total can only output 50hp more than the 85D because of the battery, however in the case of torque sleeping the front motors, the P85D can output 200+ more hp on the rear motor. This difference would not be represented in a system number.

Now let's go back to a hypothetical world of system power (Tesla never focusing on motor power) to see how the numbers would look like.

2014 to early 2015
S60: 302
S85: 362
P85: 416
60D: ~300 (extrapolated from S60 ratio)
85D 6.1: ~360 (extrapolated from S85 ratio)
85D 6.2: 422
P85D: ~480 (extrapolated from P85 ratio)

Now
S70: 315
S85: 373
70D: 328
85D: 417
P85D: ~480 (extrapolated from P85 ratio)

With just system power number, the P85D only gets a ~60hp advantage over the P85 and 85D, but then Tesla doesn't get to illustrate how versus the P85 you are actually getting an additional 221hp motor in the front. With 85D, they don't get to illustrate the P85D rear motor is 200+hp more. I think that is why they used motor power.

Now with 20/20 hindsight, we can say that what should have done was advertise with a system number, and then the individual motor power numbers not combined together, which is what they are doing now (P85D is still missing system number and I already put the theory of the exception being there precisely because of P85D complaining). However, if you were a marketing manager back then, it would not be obvious this would be as big an issue for some people as we now know. And adding the two numbers is very intuitive too.

 

[gavinwang]

My point was that whereas the screen resolution represents what you see as an end user, the HP number quoted doesn't. For example, while the P85D loses 10% of its power by the time it reaches the wheels, a typical AWD ICE car is assumed at 35% loss.

Of course, having both a battery (or system) and motor number is the most ideal.

But I find the 691hp number acceptable because I knew what it meant and what it didn't. In practical terms, it tells me if I do a battery upgrade in the future, that is what the motors/inverters can support. I can see why however for people that assumed it meant a system power number and are of the opinion that all car manufacturers are required to advertise a system power number would find that unacceptable.

For a better part of a century, ICE car manufacturers have been advertising a number that the car can never produce in ANY part of the car and people found that acceptable also, given they knew that was the case. And in that case, it was even a number they can't legally get (requires running the car without a cat).

Also, knowing the individual numbers in the dual motor case is useful because the battery can output enough to support one at a time, while a combined system number would not reflect that. For example, an EV with a 300 hp battery and 300 hp front and rear motors adding to 600hp will perform better than one with 150 hp front and rear motors adding to 300hp, even though under a conventional rating, they would be the same number. I think this was the same motivation for Tesla (why they introduced it with the dual motors).

Please enlighten me with a few examples in RECENT history of automobiles that a ICE car couldn't produce the stated HP at ANY part of the car, AND the discrepancy was as big as 15-20%. It's not unexpected that we can't recreate the exact nitpicky conditions the carmaker uses to produce their stated spec ---- we might not be able to reproduce the maximum ranges stated for model S, that is quite okay, but it's totally a different matter that the car is IN THEORY incapable of and far from producing that spec, which is exactly the case for P85D.