[updated with *] P85D 691HP should have an asterisk * next to it.. "Up to 691HP"

[krisg81]

No 'different certification' will tell anything more than current system, rather less.
Maximum power is a curve dependent on current SOC, current speed and current temperature of battery/inverter/motor.
No single number can describe that curve in a meaningful way. Stating the maximum number this curves attains at some circumstances is at least correct at exact those circumstances.
We start to near the torque/power debate.

Yes, and during this curve, which dynamically changes due to current SOC, never truly touches over 400HP according to this dyno chart. With this known, how can Tesla advertise 691HP if this curve never comes close to outputting 691HP? Any other vehicle advertised with X amount of HP can put it down to all wheels, minus drive train loss. Please let me know how this car can be marketed at 691HP, even taking the SOC power loss out of the equation?

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Exactly. The OP keeps focusing on the fact that his Corvette will put out the same HP no matter how full his gas tank is but fails to recognize that his ICE cars won't even go into legitimate launch mode until they are fully warmed up (at least not without damaging the engine), are quite susceptible to altitude changes and weather conditions. EVs have none of these limitations.

Launch mode while being warmed up? Let's stay on topic here, that is irrelevant to the discussion. We are specifically talking about power output based on current fuel/electricity levels and how motors are rated for horsepower (and marketed)

 

[SmartElectric]

I love everything about it. That is, until the battery drops below 50%. The power is noticeably reduced. Not by a little, but to where I notice the Insane mode is no longer insane- but rather reduced to what feels like the Sport mode when the SOC is lower.

First world problem to be sure. ;-)

The Smart ED keeps full power (55kW of road crushing force) until I get near 20% SOC when the battery temperature is >= -10C.
However, when it's very cold (< -10C), the power is reduced to 35kW (no longer road crushing) until about 10 minutes into the drive.
So, a top of the line P85D and a bottom of the line Smart ED both have restrictions due to battery, obviously very different absolute levels, but at least it is demonstrably similar behaviour.

Meanwhile, all of the gas cars I've ever owned (including my MB GLK) suffer worse under cold conditions.
It takes 5-10 minutes in very cold weather to get the engine up to temperature, and before then, I get well less than half power out of the car, and worse case, am abusing the engine and getting less life out of it by pushing it.

So, yes, conditions matter. Lower battery SOC or temperature or many other conditions affect ultimate performance. At least with the Tesla (and other EV), improved battery cells may solve this problem in 10 years.

 

[stopcrazypp]

The only comparison to an ICE vehicle would be saying a ICE drops performance as the gas tank empties, as thats the only thing relatively changing in my ICE vs EV comparison, especially with a P85D. The S85 and P85 are not even worth arguing- its specifically an issue with the P85D. This car is NOT 691HP, does not perform like a 691HP ICE vehicle, let alone any other vehicle with 691HP, and reduces power extremely fast after topping a charge.

To say this same anomaly happens with an ICE vehicle, with all due respect, is absurd. I can take a 700HP Corvette to the drag strip and run back to back consistent runs there and on a track and the results will be extremely consistent within a small margin of performance, with fuel/energy depletion not being a factor.

On the drag strip, the P85D actually does perform like a 691 hp car. And on the drag strip I don't think anyone actually have reported reduced performance. It's on the track where it's not the case, but that was true of all the Model S, even before the P85D.

 

[skilly]

Arijay, those are *environmental* changes due to air density as well as fuel octane rating. SAE certifications give the peak HP rating of the motor based on their testing criteria so we know all motors are rated based on the same testing conditions in order for manufactures to claim those horsepower ratings. Tesla DID NOT confirm to any type of 3rd party testing or certification process. What is occurring here is nothing to due with environmental or fuel/electricity rated changes. The fact of the matter is the car simply does not live up to its horsepower claims shortly after the full charge depleting, no matter what environmental changes occur (although it may worsen of course due to cold weather and any other issues). The car under ideal and perfect conditions will never output 691 advertised horsepower, and if it came close, will drop significantly as the battery depletes, with said battery depletion being the reason for the power loss and nothing else- the loss of available fuel/energy, apparently.

The only comparison to an ICE vehicle would be saying a ICE drops performance as the gas tank empties, as thats the only thing relatively changing in my ICE vs EV comparison, especially with a P85D. The S85 and P85 are not even worth arguing- its specifically an issue with the P85D. This car is NOT 691HP, does not perform like a 691HP ICE vehicle, let alone any other vehicle with 691HP, and reduces power extremely fast after topping a charge.

To say this same anomaly happens with an ICE vehicle, with all due respect, is absurd. I can take a 700HP Corvette to the drag strip and run back to back consistent runs there and on a track and the results will be extremely consistent within a small margin of performance, with fuel/energy depletion not being a factor.

seems to me that this rating is very similar to how Stereo receivers and amplifiers are measured. Both marketed ratings are of course based on watts; however, whats similar here is that TM is using what would be akin to a "peak" rating rather than an "rms" rating. Peak ratings are virtually useless when shopping for sound, but a great marketing hook for the uneducated shopper - RMS is a much better reflection of the performance you can expect.

Tesla should use this as an example of how to rate their HP.

 

[Danal]

To say this same anomaly happens with an ICE vehicle, with all due respect, is absurd. I can take a 700HP Corvette to the drag strip and run back to back consistent runs there and on a track and the results will be extremely consistent within a small margin of performance, with fuel/energy depletion not being a factor.

Not really. Each run will be HIGHLY dependent on temperature. My LS2 monster is really fun on cold days. Not near as fun on hot days. This can change in very short periods of time, at the track, at least in North Texas where I've seen a 70F temp change in 1 hour.

As you've said, air temp is "outside the gas tank"; nonetheless, it is quite real. Nobody complains about it because it is widely known and there is absolutely nothing that can be done about it. Simple physics.

In some ways, I have MORE control over the launch capability of the P85D, in that I can charge it between runs. I can't control the air temp. Seriously, I look forward to Fall every year when driving my ICE performance cars. With my Tesla, I can get thrills all summer long.

Probably shouldn't put up with advertising INPUT instead of WHEELS... except... ICE cars paved the way along time ago.

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Yes, and during this curve, which dynamically changes due to current SOC, never truly touches over 400HP according to this dyno chart. With this known, how can Tesla advertise 691HP if this curve never comes close to outputting 691HP? Any other vehicle advertised with X amount of HP can put it down to all wheels, minus drive train loss.

And that drive train loss is typically 20 to 30%. HUGE. Cars advertised as 400HP "at the flywheel" put 300HP "on the ground" and nobody complains. Again, because this is widely known, and therefore an "Accepted Standard". Even though it is pure marketing spin, and really shouldn't have been tolerated back when it started.

Tesla's 691HP claim is INPUT power to the motor(s). This is the "Accepted Standard" way of rating electric motors in industry, other transportation applications, etc. Lots of history behind this "de facto standard" for electrics. Volts*Amps = Watts INTO the motor. Divide by 745.699872 and you have HP. Still not hitting the wheels, and therefore absolutely equally "marketing spin".

The public probably shouldn't put up with advertising INPUT power instead of WHEELS power... except... ICE cars paved the way long ago!

That's how.

 

[stopcrazypp]

Yes, and during this curve, which dynamically changes due to current SOC, never truly touches over 400HP according to this dyno chart. With this known, how can Tesla advertise 691HP if this curve never comes close to outputting 691HP? Any other vehicle advertised with X amount of HP can put it down to all wheels, minus drive train loss. Please let me know how this car can be marketed at 691HP, even taking the SOC power loss out of the equation?

I have lots of doubt this dyno number represents the peak power (even the people running the dyno said they had to back down because the dyno couldn't handle it). The P85+ was clocked multiple times at 430+hp, so it's unlikely the P85D outputs less than 400hp.

That said, Tesla did change their evaluation method:

The P85 was rated at 416hp. P85D rear motor is now rated at 470hp (even though apparently it's the same motor).

The 60kWh was rated at 302 hp, 85kWh at 362hp. Now both are rated at 380 "motor hp".

 

[richkae]

Yes, and during this curve, which dynamically changes due to current SOC, never truly touches over 400HP according to this dyno chart. With this known, how can Tesla advertise 691HP if this curve never comes close to outputting 691HP? Any other vehicle advertised with X amount of HP can put it down to all wheels, minus drive train loss. Please let me know how this car can be marketed at 691HP, even taking the SOC power loss out of the equation?

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Launch mode while being warmed up? Let's stay on topic here, that is irrelevant to the discussion. We are specifically talking about power output based on current fuel/electricity levels and how motors are rated for horsepower (and marketed)

Is this dyno run for all 4 wheels or just 2 ?
If its just the rear wheels, then there is no way to see the total horsepower.

 

[skilly]

Not really. Each run will be HIGHLY dependent on temperature. My LS2 monster is really fun on cold days. Not near as fun on hot days. This can change in very short periods of time, at the track, at least in North Texas where I've seen a 70F temp change in 1 hour.

As you've said, air temp is "outside the gas tank"; nonetheless, it is quite real. Nobody complains about it because it is widely known and there is absolutely nothing that can be done about it. Simple physics.

In some ways, I have MORE control over the launch capability of the P85D, in that I can charge it between runs. I can't control the air temp. Seriously, I look forward to Fall every year when driving my ICE performance cars. With my Tesla, I can get thrills all summer long.

Probably shouldn't put up with advertising INPUT instead of WHEELS... except... ICE cars paved the way along time ago.

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And that drive train loss is typically 20 to 30%. HUGE. Cars advertised as 400HP "at the flywheel" put 300HP "on the ground" and nobody complains. Again, because this is widely known, and therefore an "Accepted Standard". Even though it is pure marketing spin, and really shouldn't have been tolerated back when it started.

Tesla's 691HP claim is INPUT power to the motor(s). This is the "Accepted Standard" way of rating electric motors in industry, other transportation applications, etc. Lots of history behind this "de facto standard" for electrics. Volts*Amps = Watts INTO the motor. Divide by 745.699872 and you have HP. Still not hitting the wheels, and therefore absolutely equally "marketing spin".

The public probably shouldn't put up with advertising INPUT power instead of WHEELS power... except... ICE cars paved the way long ago!

That's how.

This is kind of muddying the waters to illustrate your point. First, a 70F weather change is quite an outlier so lets call it what it is - not likely to be experienced by most people ever. Considering a more realistic temp change (so +/- 20F from spec) the electronics in cars today will account for most of that with on the fly air/fuel mix adjustments. So, HP fluctuation will be minimal and mostly non-detectable. The P85D and general characteristics of the EV are MUCH more dramatic, which as really the point of the OP.

Second, HP being measured at the flywheel or at the wheels is noticeably different, but I disagree that its just a "given" that people know this. Car people will; dyno people will; racers will. What's more to the point is that its a fairly common way to report HP on a car, so its more a level set on the marketing than recognition that the measurement isn't accounting for usable HP.

I go back to my statement a few posts back - EV posting of HP is akin to the Amplifier Watt rating. Peak, meaning it is possible to hit that rating for a short time, is FAR less valuable to the buyer (and listener) than the RMS rating that states the watts (or HP perhaps) that it can sustain while under power. Maybe in TM's case, they provide both to set the record straight and avoid confusion all together.

 

[ScepticMatt]

Yes, and during this curve, which dynamically changes due to current SOC, never truly touches over 400HP according to this dyno chart. With this known, how can Tesla advertise 691HP if this curve never comes close to outputting 691HP?

This dyno measurement used a dummy front roller (as you can see here). It only measures rear motor hp.
It is fine for ICE AWD cars with a mechanical link, but it doesn't work with multiple independent motors/engines.

Edit: So instead of something like this mustang dyno:

They need something with dual rollers

 

[sorka]

The rear wheels kept slipping. They didn't get a hookup until the third run and even then they had to take it easy on the throttle and gradually bring it up which they did full at about 30 MPH. This is why the torque curve is not flat at the beginning.

The remarkable thing here is that when they finally pressed the pedal all the way the floor at 30 MPH, the torque was 864 lbs, but we know that by 30 MPH, the system is already reducing current, so the torque would have been quite a bit more at 0 RPMs.

Typical cars lose about 15 to 20% at the rear wheels. But the Tesla has the motor right there and only goes through a reduction gear, so if the loss is only 10%, that's still 460 hp at the motor...for just the rear motor.

What everyone is eagerly awaiting for is update that improves the 0-60 time by .1 seconds not because we want a faster 0-60 time, but because it implies that they're going to allow more current at higher speeds, not just launch.

The second test drive I took, the rated miles left was about 150. I noticed no difference between that and the one I took the week before when the rated miles was 190.

Also, the voltage drop from an 80% SOC to 10% so is only about 10%. The curve is pretty flat.

Additionally, several P85D owners have claimed they didn't notice any drop off in insane mode launches until the rated miles dropped below 50.

Perhaps there's an issue with the OPs PD?

 

[fadkar]

Basically, we can agree that Teslas right now aren't ultra high performance track cars. The P85D has immense power in the range that the average person will spend a lot of time in (0-60). I do wish that the power wasn't throttled so aggressively...

 

[qwertzy]

Not necessarily. A lower SOC (with corresponding lower voltage) does not necessarily mean you will have a lower power output from the battery. You can increase the amperage draw to compensate for the lower voltage to get the same power output. The problem is with more amps you generate more heat in the power electronics, motor, and battery and begin to exceed the capacity of the cooling system. In addition, as the SOC gets low, you reach a point where the momentary voltage sag from a high-amp draw event can temporarily reduce the battery voltage below or near its minimum safe level. If you don't limit power at that point you will quickly reduce battery life.

So without overheating being an issue it should function just like powertools should with lithium ion battery technology as they state fade free power until it hits zero.

 

[sorka]

There's no way, given the technology that we can expect full 480 KW draw at all times without limitations. The life of the battery would be severely degraded over time. Tesla is trying to get these things to last 10+ years.

What I would like to see is the ability to apply 480 KW at any time *provided* certain conditions are met such as the battery is within a certain temperature range and the SOC is at least 20%. This way you could do a really fast pass on the freeway but then you might have to wait 5 minutes before you could do it again depending on the state of the battery.

Currently(no pun intended), even if you're fully charged and driving at 60 MPH and you punch it, you won't get anywhere near 480 KW even if the battery is in the perfect temperature range.

Hopefully the 6.2 update coming will fix that as many are hoping.

 

[fiksegts]

the car does NOT perform like a 691HP car at the drag strip.... the trap speed is VERY low as the car pulls back power after 90MPH or so. The P85D should be running low 11's at 121+ MPH. Maybe with the top speed update from 135 MPH to 155 MPH the highway pulling power will increase as well. But still, I agree, it's not 691HP all the time, aside from the SOC, the power drops off as speed increases as well.

On the drag strip, the P85D actually does perform like a 691 hp car. And on the drag strip I don't think anyone actually have reported reduced performance. It's on the track where it's not the case, but that was true of all the Model S, even before the P85D.

 

[sorka]

The P85D weighs 5000 lbs. It's not going to be quite as fast at the strip as the 3500 lb competitor with the same power.

 

[Danal]

This is kind of muddying the waters to illustrate your point. First, a 70F weather change is quite an outlier so lets call it what it is - not likely to be experienced by most people ever

You obviously never lived anywhere that weather lines move across on a regular basis. This does apply to a lot of people. Nonetheless, let's not debate this, let's just go with your next sentence:

Considering a more realistic temp change (so +/- 20F from spec) the electronics in cars today will account for most of that with on the fly air/fuel mix adjustments. So, HP fluctuation will be minimal and mostly non-detectable. The P85D and general characteristics of the EV are MUCH more dramatic, which as really the point of the OP.

No. The adjustments will keep the mixture correct for the reduced mass airfow. Less air through the engine = less power, period. Unless we are talking about a turbo or super charged car with a constant boost (not offset from atmospheric). Lots of airplanes work that way (its called "turbonormalized" in airplanes), but few cars. Anyway, for a normally aspirated engine, per SAE J1349 Revision JUN90 (industry standard for correcting dyno readings) a 20F increase in intake air temp (and the associated humidity change that happens in the real world) makes about a 5% reduction in power. Without knowing more about the Tesla's software controls, it is very hard to say what SOC change causes a parallel 5% difference.

Second, HP being measured at the flywheel or at the wheels is noticeably different, but I disagree that its just a "given" that people know this. Car people will; dyno people will; racers will. What's more to the point is that its a fairly common way to report HP on a car, so its more a level set on the marketing than recognition that the measurement isn't accounting for usable HP.

Aboslutely agreed. Most people DON'T know this, which is why it used for marketing spin.

I go back to my statement a few posts back - EV posting of HP is akin to the Amplifier Watt rating. Peak, meaning it is possible to hit that rating for a short time, is FAR less valuable to the buyer (and listener) than the RMS rating that states the watts (or HP perhaps) that it can sustain while under power. Maybe in TM's case, they provide both to set the record straight and avoid confusion all together.

Great metaphor!

In ICE cars, despite decades of marketing, HP doesn't mean near as much as Torque. And the real key metric is "area under the torque curve". But that's not as easy to sell...

 

[krisg81]

I think based on some responses here, some people are not understanding the point I am trying to make. Why argue over temps affecting an ICE car and its performance make no sense to me. Whoever said an ICE vehicle loses 20-30% power to the wheels on a dyno is also a bit nuts.. more like 12-15% for FWD/RWD and 17-18% for AWD. How do I know this? Well, over 17 years of dyno tuning many vehicles on Dynojet and Mustang dynometers. A lot of misinformation being said here, unfortunately.

My issues are as follows:

1) The P85D clearly does not perform like a 691 HORSEPOWER vehicle. Maybe 691lb-ft of torque like a Diesel, but a 691HP vehicle would not lose power significantly after 40-50MPH and feel like its 380HP (S85) and 417HP (P85) counterparts if performing as *advertised*, a 691 horsepower "Fastest Sedan ever made". More like "Quickest 0-60 sedan ever made" possible, but fastest? No.

2) The STATE OF CHARGE, not environmental factors are causing reduced performance. Insane mode only is only insane for half the battery charge at most. I am willing to bet someone will be testing this and proving that Insane mode is reduced to Sport mode at some point along the battery depletion range. If the car cannot perform at the advertised 691HP levels with various levels of charge, Tesla needs to be more transparent when advertising this. Imagine of the SRT Hellcat ran in 500HP vs 707HP mode when the tank was half full? ONCE AGAIN, I don't care if its 70* vs 90* and the Hellcat loses 30HP at the drag strip or the driver can't launch it vs launching a P85D THATS NOT THE POINT. The Hellcat doesn't lose significant amounts of advertised power based on its CURRENT LEVEL OF FUEL RESOURCES AVAILABLE TO IT.

3) I strongly think the INSANE button should be greyed out when it no longer can perform at the advertised 3.2 second 0-60 mode so it is clear the car is not performing in its high performance mode. Don't trick the driver into thinking the full 3.2 second 0-60 Insane mode is working when in fact the car is physically unable to do so.

The guy who said advertising the Peak wattage vs RMS wattage for stereo amps is right on. Just like Sony would claim a 1,000 WATTS OF POWER amp yet only have 250w of RMS was pure marketing gimmick. I think this 691HP rating is gimmick, plain and simple. Is the car quick? Hell yes and I love it. But that quickly goes away based on battery charge and the 691 horses are non-existent at anything other than a launch which sucks.

Also, the trap speed is WAY too low for a 691HP vehicle. Trap speeds are how you base HP vs torque. I don't care if the car is almost 5000 lbs. Look at the 2014 Mercedes E63 AMG with 577HP and 4,500 lbs. It has 114 horsepower less and traps at 121MPH or better compared to the P85D's 115-116MPH. In fact, the trap speed of the P85D is equivalent to a 5,000lb 475HP ICE vehicle which isn't good for a vehicle claiming to be almost 700HP.

Also, the P85 with only 417HP would trap at 110MPH.. what gets me is Tesla advertises the P85D at 691HP but it only traps 5-6MPH higher in the 1/4 mile than the P85 with 274HP less. Something doesn't seem right there.

 

[Danal]

Kris... all we are saying is that every number for every type of car is subject to a LOT of "correct for this, correct for that". They are all marketing, not reality.

Stack an EV up against years of assumptions about ICE and it seems very strange. Stack an ICE up against an EV, where the driver can totally control every factor, including charge, and the ICE looks really weird.

No right or wrong, just different.

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And... as I said, HP doesn't tell the story. Your trap speed comparisons are based on differences in where the torque occurs. On the street, I'll love the capabilities below 60 (of any car, not just the P85D), on the 1/4 mile, I'll take capability at a somewhat higher speed range, and on a road track, I will care a lot more about handling and brakes than about power, no matter where the best torque band is.

 

[supratachophobia]

This comment is not helpful in any way. But I cant believe this thread took this long to generate. I mean, looking at the numbers alone and the output of the 85kw battery on the P85 and it's power reduction methodology. How could any of you (us) ever think that it was actually going to put out 691HP at once at any given time and/or somehow not go into power reduction sooner on a P85D?

Yes the 0-60 is quick, but the 1/4 mile times suffer from the same problem that the P85 did and that is everything does or almost does catch up in the end. 110KW battery is the only way you'll see some sustained 691/940HP runs on the track or on the road.

Also, OP, have them check the front fans. I had one that had been left completely unconnected from the factory. The oddest thing was that I received no warning as a driver whatsoever. Which is a great segway(sp?) into why there should be a detailed info/diagnostic screen available to the driver that lists coolant temp, fan speeds, tire pressure/temp, output voltage/amp, battery module temps, etc.

 

[Danal]

the output of the 85kw battery on the P85 and it's power reduction methodology.

Could you elaborate? With numbers?