Tesla blog post: AWD Motor Power and Torque Specifications

[schonelucht]

Hey if you can pick one component why not pick another to back you HP numbers? When Tesla said the car had 691HP based on the motor rating alone, would it be equally ok for Tesla to say the car was 1500HP because the drive shaft is rated to sustain forces induced by such power throughput? Of course not. It's patently absurd and misleading to advertise with the famous 'added motor rating number' and now that they have clarified this was the intention behind that number right from the very start instead of an honest engineering mistake in how much power delivery they could squeeze out of their battery, it means they intentionally misled potential customers right from the very first reveal.

I said it before and I'll say it again : that's right up there with VW, except that with VW there is actually a feasible configuration where the car hits the numbers...

 

[stopcrazypp]

Hey if you can pick one component why not pick another to back you HP numbers? When Tesla said the car had 691HP based on the motor rating alone, would it be equally ok for Tesla to say the car was 1500HP because the drive shaft is rated to sustain forces induced by such power throughput? Of course not. It's patently absurd and misleading to advertise with the famous 'added motor rating number' and now that they have clarified this was the intention behind that number right from the very start instead of an honest engineering mistake in how much power delivery they could squeeze out of their battery, it means they intentionally misled potential customers right from the very first reveal.

I said it before and I'll say it again : that's right up there with VW, except that with VW there is actually a feasible configuration where the car hits the numbers...

The difference between that two is that giving only the motor power meets EU standards (ECE R85). Giving just the driveshaft rating doesn't and there is no precedence for that, whereas giving motor ratings is quite common in the EV world.

For example Straubel's 944 used two 203-06-4001 motors.
http://www.evalbum.com/223
You can find the motor power ratings here:
http://evolveelectrics.com/advanced-motors-and-drive-dc/adc-motor-203-06-4001/

In VW's case they directly violated a law that prohibits defeat devices.

 

[AnxietyRanger]

flathillll:

We are talking about actually less peak HP in all measurements: 1) the ECU, 2) the dyno, 3) the weight to power ratio compared to key competition, 4) the known bottleneck, the battery limit - everything numerical we have on the P85D, excluding Tesla's original HP claim - says the road gets, combined, somewhere in the ballpark of 550 hp (peak).

And something around that number is, quite simply, what Tesla should have advertised upon launch - or not advertised a combined HP number at all.

The point here is not that Tesla should promote battery HP. The point here is that Tesla should honestly promote a realistic peak HP - or if not that, then clearly explain what they are promoting and how it differs from the common understanding of HP. Just like Volkswagen should promote realistic NOx compliance. Your suggestion that Tesla should promote an HP figure the car is not able to produce, just to make the car more appealing and protect sales, is frankly outrageous. Even Tesla seems to have seen the error in their ways and stepped away from that. They are yet to fix it all, though, and what they did was questionable still.

It is one thing to express the HP of the individual motors, as they do now, we can at least think those can theoretically happen in a dynamic adjustment of front/rear torque split (say, front on ice and back on asphalt). It can still be misleading when expressed without a clear disclaimer, but at least it is theoretically defendable. But it is quite a bit worse to express their combined output when that can never be reached, yet this is exactly what Tesla did when they launched the P85D and a lot of people (literally) bought it. There were voices on TMC saying that is unrealistic - and eventually those voices turned out to be right. People disparaged those voices for disagreeing with and not believing in Tesla, as often happens. And yet these objective voices were right, as often happens. (Now one of those voices is silenced and we're that much less wiser, but that is not your doing.)

One way to get a realistic HP reading is a dyno. It doesn't care what causes what, it just measures what the road gets. If you feel battery HP is not that realistic number, fine. However, what the road gets is - let's use a number from a dyno then. If not the dyno, then at least the ECU. But in this case not even that is producing figures anywhere near 691 HP in the case of the P85D, so we are not talking about some mythically "hard to dyno" car... In any case, that and the fact that the relative weight to power ratio, battery power limit and pure logic also line up to support this is just gravy. What the road gets matters, unless the car was producing forces not measurable from the road - and until those falcon wings flap a Model X up the sky, such considerations are not relevant on TMC.

And the road gets around 550 hp at peak on P85D. Maybe 555 hp. Maybe some other number nearby.

Volkswagen seems more honest with their NOx than Tesla was with the HP of P85D, given that Volkswagen actually is able to produce that NOx in certain cirtumstances. Perhaps P85D should at least detect it is on a dyno and produce 691 HP momentarily somehow...

 

[smac]

I am an EE/ME and have designed both controllers and motors

Please can you explain it to us then? (Or send us to links which do similar)

I'm confused you say it's not down to PF, and it's down to output phase amps. (Presumably you mean there are now two inverters in play, and internally these are boosting the current on the output phase without changing the voltage, I can only assume via some internal capacitance.)

One of the valuable things about TMC is as a learning tool, so please help us learn!

 

[scottf200]

What I meant by move on is that we can all stop arguing about what Tesla did or didn't mean.

Not directing this directly to sorka. So Tesla provided the numbers and it may have been some 'advertising' PR. People test drove the car, tho, AND still made their OWN personal decision to make the purchase. People should take responsibility for their choice to make the purchase. If people bought it without DD then that is on them. They could have waited until others purchased and reviewed, charted, dragged it, etc, etc. Whatever the case is people wrote the check and now they are looking to blame someone beside themselves. They OWN "it" in more ways than one. Why aren't people looking in the mirror when they want someone to blame? This latest few day old thread is 20 pages long. Why can't people move on?

 

[ProSkeptic]

...everything numerical we have on the P85D, excluding Tesla's original HP claim - says the road gets, combined, somewhere in the ballpark of 550 hp (peak)...

One small point of order - If one were to actually put the P85D on a four-wheel dynamometer, it would not measure anywhere near 550 hp/410 kW. While that is the maximum power rate that the battery can output, there are losses in the inverter, the motor, the reduction gear, and all the other physical 'imperfections' that exist between battery contactors and pavement. This is supported by Tesla's own (repeated) claim that the P85D is traction-limited up to 30 mph. A 5000 lb car accelerating at 1 g at a speed of 30 mph is putting roughly 400 hp/300 kW to the pavement.

 

[sorka]

Not directly this directly to sorka. So Tesla provided the numbers and it may have been some 'advertising' PR. People test drove the car, tho, AND still made their OWN personal decision to make the purchase. People should take responsibility for their choice to make the purchase. If people bought it without DD then that is on them. They could have waited until others purchased and reviewed, charted, dragged it, etc, etc. Whatever the case is people wrote the check and now they are looking to blame someone beside themselves. They OWN "it" in more ways than one. Why aren't people looking in the mirror when they want someone to blame? This latest few day old thread is 20 pages long. Why can't people move on?

Buyer beware. Buy at your own risk. Don't trust what the company publishes. If you still buy after figuring it out all on your own instead of believing the company then it's your fault. Companies should be free to publish whatever they want and if you buy it believing it without doing *enough* research to figure out what they published wasn't true, that's your fault. Too bad for you.

 

[FlasherZ]

Buyer beware. Buy at your own risk. Don't trust what the company publishes. If you still buy after figuring it out all on your own instead of believing the company then it's your fault. Companies should be free to publish whatever they want and if you buy it believing it without doing *enough* research to figure out what they published wasn't true, that's your fault. Too bad for you.

I don't think anyone is saying that at all. Tesla chose to publish numbers that were theoretical motor numbers, the sum of both motors operating at full blast with no other constraints, at once.

There's the question of how they calculated it: Some expected Tesla to provide the peak maximum HP the system would deliver via tires-to-road, including battery. Some expected Tesla to provide the peak maximum HP the motors would deliver, working together in the software, without drivetrain losses but with battery. Some had other ideas. This means some are going to be concerned and/or angry with what was published. It does not mean Tesla lied, or played fast and loose with the numbers - but they were a bit creative in making their product look good. It is indeed the buyer's responsibility to ensure that it's suitable for their application in all ways, or choose not to buy it.

Then there's the question of "what difference does it make"? Some just want an awesome experience and the numbers aren't important. Some wanted to be able to tell their friends that they have the biggest HP motor power. Some wanted to outrace their buddy's M5 to prove superiority. Some people live for numbers and want extreme accuracy - for whatever reason.

This reminds me of the early days of networking equipment, when there were network test houses like Tolly that would happily take a company's money in exchange for producing test conditions that would always help the payer look good. Network equipment that could forward traffic at full line rate with big packets were limited somewhat when fed a representative mix of Internet traffic, yet were shown to pass with flying colors. It wasn't a lie, but it was structured to that vendor's strengths (and avoided their weaknesses).

"Caveat emptor" is indeed still an important element.

 

[sorka]

I don't think anyone is saying that at all. Tesla chose to publish numbers that were theoretical motor numbers, the sum of both motors operating at full blast with no other constraints, at once.

There's the question of how they calculated it: Some expected Tesla to provide the peak maximum HP the system would deliver via tires-to-road, including battery. Some expected Tesla to provide the peak maximum HP the motors would deliver, working together in the software, without drivetrain losses but with battery. Some had other ideas. This means some are going to be concerned and/or angry with what was published. It does not mean Tesla lied, or played fast and loose with the numbers - but they were a bit creative in making their product look good. It is indeed the buyer's responsibility to ensure that it's suitable for their application in all ways, or choose not to buy it.

Then there's the question of "what difference does it make"? Some just want an awesome experience and the numbers aren't important. Some wanted to be able to tell their friends that they have the biggest HP motor power. Some wanted to outrace their buddy's M5 to prove superiority. Some people live for numbers and want extreme accuracy - for whatever reason.

This reminds me of the early days of networking equipment, when there were network test houses like Tolly that would happily take a company's money in exchange for producing test conditions that would always help the payer look good. Network equipment that could forward traffic at full line rate with big packets were limited somewhat when fed a representative mix of Internet traffic, yet were shown to pass with flying colors. It wasn't a lie, but it was structured to that vendor's strengths (and avoided their weaknesses).

"Caveat emptor" is indeed still an important element.

I would call what they're doing now as fast and loose. Even though Tesla has is no longer publishing a combined number, consumers are still adding these numbers up. Technically they're not lying now as each motor by itself can deliver the speced power with the supplied battery, but it's easy to see how consumers are assuming that both motors are operating at full power together at some point.

Before, when they published a combined number, most of us assumed that number was the power the car actually made and not a number based on adding up two motors capability. This was an outright lie. What they're doing now is fast and loose and they really should make it clear that 691 or 762 is not the total combined power that the car actually makes.

I know you don't agree with this so we'll just agree to disagree.

 

[stopcrazypp]

There's the question of how they calculated it: Some expected Tesla to provide the peak maximum HP the system would deliver via tires-to-road, including battery. Some expected Tesla to provide the peak maximum HP the motors would deliver, working together in the software, without drivetrain losses but with battery. Some had other ideas. This means some are going to be concerned and/or angry with what was published. It does not mean Tesla lied, or played fast and loose with the numbers - but they were a bit creative in making their product look good. It is indeed the buyer's responsibility to ensure that it's suitable for their application in all ways, or choose not to buy it.

This is the core issue I see. Many people made their own assumptions about what "motor power" meant. A lot of those turned out to be wrong. I still see many claims about how any standard that does not factor in the battery is false advertisement or an outright lie. I would only agree to that if Tesla specified they were using a standard that does factor in the battery or if it is at least industry convention to use such a standard. However there is no published SAE standard for EVs that is the defacto standard (unlike for ICE cars). Tesla apparently used an existing EU standard that does not factor in the battery.

Tesla does take some partial blame for not making clear what "motor power" means (this blog post really should have been posted a long time ago) and I think the $5000 Ludicrous is their way of saying mea culpa for that. What they did not expect perhaps is that there are those that wanted more (free Ludicrous).

About the whole roll-out thing, their way of addressing it seems to be adding the battery heat mode to non-Ludicrous vehicles.

 

[Andyw2100]

Tesla does take some partial blame for not making clear what "motor power" means (this blog post really should have been posted a long time ago) and I think the $5000 Ludicrous is their way of saying mea culpa for that. What they did not expect perhaps is that there are those that wanted more (free Ludicrous).

Could we please stop talking about $5000 Ludicrous? When Musk announced it, he announced it as $5000, plus installation costs. When people here tried to get an idea of what those costs might be, the numbers were estimated to be in the $2000 range. So $5000 Ludicrous is really "About $7000 Ludicrous", making the "discount" about $3000, give or take.

 

[flathillll]

Please can you explain it to us then? (Or send us to links which do similar)

I'm confused you say it's not down to PF, and it's down to output phase amps. (Presumably you mean there are now two inverters in play, and internally these are boosting the current on the output phase without changing the voltage, I can only assume via some internal capacitance.)

One of the valuable things about TMC is as a learning tool, so please help us learn!

Peak battery hp (power output or kW) is directly correlated to the peak hp output to the wheels (minus motor/wiring/inverter losses). This is because in the P85D and P90D the battery is the limiter on output. I'm calling output to the wheels "car hp" just to make it easier to reference. So in this context peak car hp is directly proportional to peak battery hp.

Below the speed where the car reaches peak car hp (peak batter hp), the battery is not the limit on acceleration. If you added more "motor" the car would accelerate faster assuming it is not traction limited. When I say more "motor" I mean the motor/inverter system.

It is important to understand phase amp vs battery amps because the inverter (aka controller) is like a buck inverter, meaning it steps down voltage and steps up current. If the controller is drawing let's say only Xb battery amps from or whatever at 10mph at full throttle, the phase amps Xp could be many multiples of Xb. Xb at 10mph is well below the Xbmax (which sets the limit on car hp).

The best way to get a feel for this is not reading a textbook. Try playing around with this simulator. Note here Mtr amps is what I call phase amps. Also note these are BLDC motors, but the same applies to an AC induction motors. Note at low speeds "Mtr Amps" exceeds the "Battery Amps." Play around with the throttle and see the effect. Note these are wheel motors in the simulator but by changing the wheel size you effectively change the gear ratio.

Motor Simulator - Tools

 

[brianman]

Not directing this directly to sorka. So Tesla provided the numbers and it may have been some 'advertising' PR. People test drove the car, tho, AND still made their OWN personal decision to make the purchase. People should take responsibility for their choice to make the purchase. If people bought it without DD then that is on them. They could have waited until others purchased and reviewed, charted, dragged it, etc, etc. Whatever the case is people wrote the check and now they are looking to blame someone beside themselves. They OWN "it" in more ways than one. Why aren't people looking in the mirror when they want someone to blame? This latest few day old thread is 20 pages long. Why can't people move on?

Signature (United States) # 603: MODEL X P90DL

I sincerely hope this post doesn't backfire on you but, unfortunately, Tesla's track record with "P*D" strongly suggests it will.

That said, for the benefit of those that will configure after you please contribute your thoughts and data on how your X performs so that they can make a better informed decision when their configuration dates arrive.

 

[gnxs]

It was reported by 50 different sources on the same day. Do you think they all came up with 11.8 from thin air? That was Tesla's announced performance number. It's patently false that there wasn't a target performance of 11.8 in the 1/4.........

Exactly.

Add to that the fact that more than one owner has achieved 11.5x in the 1/4 mile in different locations of the US (FL and CO if I remember correctly).

 

[FlasherZ]

I would call what they're doing now as fast and loose. Even though Tesla has is no longer publishing a combined number, consumers are still adding these numbers up. Technically they're not lying now as each motor by itself can deliver the speced power with the supplied battery, but it's easy to see how consumers are assuming that both motors are operating at full power together at some point.

Before, when they published a combined number, most of us assumed that number was the power the car actually made and not a number based on adding up two motors capability. This was an outright lie. What they're doing now is fast and loose and they really should make it clear that 691 or 762 is not the total combined power that the car actually makes.

I know you don't agree with this so we'll just agree to disagree.

Actually, I agree with every point you make, including the assumption that many/most made - the only thing I disagree with is the "fast and loose" description, only because it's "fast and loose" based upon the reader's point of view. For the techie in me, I want to know how they determined the numbers so that I can make the right decision if the HP motor power is important to me (although on my care-o-meter, it's more about the experience than the number itself).

 

[Johan]

Following this thread all I can think of is how much better off Tesla and all of us would have been if they published 0-60 times, 1/4 mile times, torque numbers but no horsepower number. If pressed on this they should have simply stated that the horsepower metric gives little meaning to a prospective buyer and that comparisons to ICEs using a hp number is of little value as the drive train is so different in every other aspect.

 

[dsm363]

Following this thread all I can think of is how much better off Tesla and all of us would have been if they published 0-60 times, 1/4 mile times, torque numbers but no horsepower number. If pressed on this they should have simply stated that the horsepower metric gives little meaning to a prospective buyer and that comparisons to ICEs using a hp number is of little value as the drive train is so different in every other aspect.

That would be great. The numbers mean so little to the overall experience anyway.

 

[ProSkeptic]

Following this thread all I can think of is how much better off Tesla and all of us would have been if they published 0-60 times, 1/4 mile times, torque numbers but no horsepower number. If pressed on this they should have simply stated that the horsepower metric gives little meaning to a prospective buyer and that comparisons to ICEs using a hp number is of little value as the drive train is so different in every other aspect.

Yeah, but what fun would that be?

The danger in feeling compelled to whip it out and compare size is that one runs the risk of it being trod upon.

 

[Johan]

Yeah, but what fun would that be?

The danger in feeling compelled to whip it out and compare size is that one runs the risk of it being trod upon.

I see your point. However this could have been another instance where Tesla could have proven that they are different, the next generation of auto maker, something other than what we've been used to in the past (I mean in the way the electric drive train is different, the direct sales model, the [alleged] service without profit model, the prepaid long distance fuel for life model etc).

 

[Andyw2100]

However this could have been another instance where Tesla could have proven that they are different, the next generation of auto maker, something other than what we've been used to in the past (I mean in the way the electric drive train is different, the direct sales model, the [alleged] service without profit model, the prepaid long distance fuel for life model etc).

Unfortunately they did not, which leaves us where we are today.