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

[stopcrazypp]

Electric motors can be rated by peak or continuous power (which is independent of the inverter/battery ratings). This is a common rating when you buy a motor separately.

For what it's worth, Fisker did the same thing. They advertised dual 150kW motors (300kW total = 402 hp). However, it was only dynoed at 230whp, and it was immediately obvious to all owners that they weren't getting 402hp.
http://www.fiskerbuzz.com/forums/13-fisker-karma/4601-maximum-power-karma.html

 

[krisg81]

Electric motors can be rated by peak or continuous power (which is independent of the inverter/battery ratings). This is a common rating when you buy a motor separately.

For what it's worth, Fisker did the same thing. They advertised dual 150kW motors (300kW total = 402 hp). However, it was only dynoed at 230whp, and it was immediately obvious to all owners that they weren't getting 402hp.
http://www.fiskerbuzz.com/forums/13-fisker-karma/4601-maximum-power-karma.html

Thanks for this... Just makes me think we need some some 3rd party certification process like what the SAE does for ICE cars, or else we are going to have crazy HP claims for marketing reasons.. Kind of like what someone said earlier about aftermarket stereo equipment marketing claiming crazy peak wattage specs, yet RMS was much lower and what actually counts.

its stuff like this that spawned the SAE Certification process: Certified Power (SAE J1349 and J1995) - SAE International

"Power and torque certification provide a means for a manufacturer to assure a customer that the engine they purchase delivers the advertised performance. This SAE Standard has been written to provide manufacturers with a method of certifying the power of engines to SAE J1349 or SAE J1995. Document SAE J2723 specifies the procedure to be used for a manufacturer to certify the net power and torque rating of a production engine according to SAE J1349 or the gross engine power of a production engine according to SAE J1995. Manufacturers who advertise their engine power and torque ratings as Certified to SAE J1349 or SAE J1995 shall follow this procedure. Certification of engine power and torque to SAE J1349 or SAE J1995 is voluntary, however, this power certification process is mandatory for those advertising power ratings as "Certified to SAE J1349"."

 

[stopcrazypp]

Thanks for this... Just makes me think we need some some 3rd party certification process like what the SAE does for ICE cars, or else we are going to have crazy HP claims for marketing reasons.. Kind of like what someone said earlier about aftermarket stereo equipment marketing claiming crazy peak wattage specs, yet RMS was much lower and what actually counts.

The thing is I have no doubt Tesla's motors would meet an SAE test at the given ratings. Remember Tesla is advertising their motor(s) can generate that much power. If you throw their motor on a motor dyno, it'll likely be able to make that much power. And independently, it might be the case that even in the P85D the rear motor as installed in the car makes 470hp, and the front 221 hp, even though not at the same time.

If that were the case, and from what I recall with the front and rear motor inverters being independent, that means the inverters would not be the bottleneck. That would mean the bottleneck is at the battery (or total cooling system).

 

[krisg81]

The thing is I have no doubt Tesla's motors would meet an SAE test at the given ratings. Remember Tesla is advertising their motor(s) can generate that much power. If you throw their motor on a motor dyno, it'll likely be able to make that much power. And independently, it might be the case that even in the P85D the rear motor as installed in the car makes 470hp, and the front 221 hp, even though not at the same time.

If that were the case, and from what I recall with the front and rear motor inverters being independent, that means the inverters would not be the bottleneck. That would mean the bottleneck is at the battery (or total cooling system).

yes and I agree that it would likely show advertised horsepower at a FULL charge.

My problem (and why I started this thread) is that advertised horsepower obvious diminishes based on charge level, so much that it is noticeably slower under 50% and drastically drops below that.

if there was to be an SAE certified process for EVs, I feel the certified amount should take into account the average horsepower output across SOC charge states. Just because the motor(s) can output Xxx amount of HP at a full charge state, I don't think it's fair a company can market that peak HP level if it's only able to output that for a small amount of time based on fuel / energy levels.

Like SAE certifying an ICE motor that puts out 650HP with a full gas tank, yet at half empty it puts it 30-40% less power. That just wouldn't fly.

 

[Denarius]

yes and I agree that it would likely show advertised horsepower at a FULL charge.

My problem (and why I started this thread) is that advertised horsepower obvious diminishes based on charge level, so much that it is noticeably slower under 50% and drastically drops below that.

...

Like SAE certifying an ICE motor that puts out 650HP with a full gas tank, yet at half empty it puts it 30-40% less power. That just wouldn't fly.

You keep throwing these random numbers out based on your butt Dyno. Can we give this a rest until we get some actual facts?

 

[krisg81]

You keep throwing these random numbers out based on your butt Dyno. Can we give this a rest until we get some actual facts?

You have a P85D so are you telling me you don't feel a huge difference with a full charge vs 50% and below? Sure, having data would be nice- but what's your experience?

 

[wk057]

You have a P85D so are you telling me you don't feel a huge difference with a full charge vs 50% and below? Sure, having data would be nice- but what's your experience?

Going to jump in here, as a P85D owner about to hit 5k miles.

There is virtually no noticeable difference in launches at 100% vs 50%. Anyone who says otherwise is exaggerating. The 0-60 time doesn't even suffer much between 100% and 50%. We're talking time differences that can't even be determined within a reasonable margin for error (+/- 0.15 seconds).

Even at 30% the car will pin you to the seat from 0 MPH. According the accelerometer on my dash cam a launch at 30% is indistinguishable from a launch at 100%. Granted this accelerometer isn't designed for this type of accuracy, but neither is your butt's accelerometer. If my dash cam's digital accelerometer can't tell the difference, I promise that you can't either.

Around 25% is where I start seeing a noticeable drop in launch power. And by noticeable I mean inching towards P85 performance, which is still very good. While I haven't done enough data gathering on this to have numbers behind it, like above, at about 20%-15% the P85D has about the same performance as a P85 based on the feel of things. Below 15% and we've dipped below that, and the dashed power limit line is visible soon also (just like other variants).

 

[Matias]

You said Tesla acknowledged, but I don't believe Tesla has acknowledged anything. Your link is not to something Tesla acknowledged. I think you are ascribing to Tesla something you read in a blog post.

Tesla should be more open about this motor power vs. actual power with battery-inverter-motor combination.

It is better to be proactive than reactive. Otherwise it will definitely make backfire sooner or later. If they have nothing to hide and want to act in good faith, why not putting some footnote explaining this.

 

[tidalsails]

Power decrease on P85D

Ok, so have had my P85D for several days now and putting 500+ miles on it, I have observed something interesting here and wanted to get thoughts on it from the crowd here.

Keep in mind, I traded in my P85 for this.

First off, the P85D is AWESOME. The launch is killer and the AWD is great. It also handles very well and I am loving the Pilot Cup tires that come on it stock, big thumbs up from me on that department!

That is also the issue. 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. It may even happen sooner than 50%. Know that I rarely noticed any performance difference in my P85 unless the little yellow power reducing line showed up when the battery was really low.

As it is, the P85D does not feel much faster than my P85 when fully accelerating after 40-50MPH. When it is below 50% battery, I swear.. it feels slower than my P85 did at almost any charge level.. yes, slower.

I get the P85D hype with the 691HP and I do get how they calculate it, but why I do I feel somewhat cheated this is not a full time 691HP vehicle? If this was a 691HP Lamborghini, Porsche, Ferrari, etc ICE vehicle rated at 691HP, that horsepower claim would be SAE certified and would make that power until the very last drop of gasoline was consumed. Imagine if you bought a 577HP Mercedes E63 AMG that operated much slower when the gas tank was 1/2 full? That would be strange.

Maybe I don't understand the hardware reasons of why the car must reduce power based on SOC. If I have this bad boy in INSANE mode, then.. STAY INSANE until I decide to charge up! I don't need it to conserve power, this mode should be the advertised 691HP at ALL TIMES. Give me a ECO mode for long range, or just recommend me to use Sport mode when the battery drops- but Elon, there needs to be a mode that can deliver advertised power regardless of battery state. Unless someone can chime in here with the hardware reasons (maybe battery pack cannot output as much power as the charge level drops) then I am slightly disappointed here, especially because the power drop happens so quickly. I wouldn't be complaining if it was dropping below 20%, but 50%? That sucks.

With that said, I really think this car should be advertised as 691HP* *Up to 691HP with ideal battery conditions

Hi, I just discussed this situation with Tesla Europe yesterday, and they never disclosed this information, but I agree - My old P85 Signature seems faster in general.
I would like to control this power conservation my self as well!

 

[WarpedOne]

Still only butt-dyno reports...
Really, is it that hard to post a YT video showing what you are talking about?

 

[LetsGoFast]

You have a P85D so are you telling me you don't feel a huge difference with a full charge vs 50% and below? Sure, having data would be nice- but what's your experience?

My personal "butt dyno" estimate is that the 0-60 time is less than 10% slower at 50% charge. I'm going to guess about 2/10th of a second slower. I'd be willing to race a P85 at 100% in my P85D at 30% for money. Tomorrow I'll have quantifiable data to post.

 

[sorka]

My personal "butt dyno" estimate is that the 0-60 time is less than 10% slower at 50% charge. I'm going to guess about 2/10th of a second slower. I'd be willing to race a P85 at 100% in my P85D at 30% for money. Tomorrow I'll have quantifiable data to post.

Unless Tesla is doing something intentionally, 50% SOC should be about 5% slower than an 80% SOC. 20% SOC should be about 10% slower. 10% is about what it takes to start noticing on the butt dyno. So I guess noticing it at 25% is close enough.

I'm shocked with the length of this thread that there isn't more data posted by those claiming one way or another.

 

[thegruf]

... and I am loving the Pilot Cup tires that come on it stock ...

Pilot CUP???

I really am struggling to believe they are standard factory fit.
Primacy, PS3, PSS maybe.
Please confirm, and any other owners for that matter.

 

[Danal]

Unless Tesla is doing something intentionally, 50% SOC should be about 5% slower than an 80% SOC. 20% SOC should be about 10% slower.

Please show your calculations?

 

[sorka]

Please show your calculations?

Your question shows you haven't been following the thread. Just look at any lithium ion discharge graph. There are millions of them online for you to find. There's a 10% drop in voltage from 80% to 20% SOC.

 

[Danal]

Your question shows you haven't been following the thread. Just look at any lithium ion discharge graph. There are millions of them online for you to find. There's a 10% drop in voltage from 80% to 20% SOC.

Thank you for the the personal comment. I am the person who posted SOC/V/A numeric tables in this thread. Derived from one of those millions of Li discharge curves. Derived specifically from 18650 cell curves. Twice.

Back to the factual discussion: Assuming that 0-60 time follows the voltage discharge curve assumes that Tesla is not limiting power at full SOC. Put more precisely, it assumes the motor controller goes to 100% PWM when the pedal is on the floor. Power being Watts, which is V*A, sagging V can be compensated by increasing A. Lots of ways for a motor controller to do that... change timing, change PWM frequency, change commutation slope, and more.

I don't know if they are or not. I do know that we need to measure, instead of assuming power follows V only.

 

[sorka]

I agree that we need more data and that this thread is curiously absent of it given just how many people on it actually have the cars and the tools to collect it.

 

[loco]

I agree that we need more data and that this thread is curiously absent of it given just how many people on it actually have the cars and the tools to collect it.

I'd love to provide data but my D is permanently limp at 4,1s regardless of SOC.

Kris, since you started the thread, why not make use of your phone camera?

 

[Danal]

I agree that we need more data and that this thread is curiously absent of it given just how many people on it actually have the cars and the tools to collect it.

I'm willing... but we all said (OK, I don't really remember who said each comment ) The dash lags, phone accelerometers arent' accurate enough, only a $3300 VBOX will satisfy, the crowd made a noise, the sun was in my eyes.

OK, I made up those last two.

I do intend to visit a 4-wheel drive Dynojet, operated by a person I trust (Brice Yingling at Alamo Autosports in Arlington, TX) and with whom I've worked before. I believe we can get REALLY solid data from that. But... it will be at least two weeks, maybe more.

Meanwhile, what would we like to see? I do have a car, an 80A HPWC, an iPhone 5s, a Canon 60D that shoots stunning video, and probably a little bit more... what I don't have is a lot of free time. So, seriously, what do we want to capture?

 

[sorka]

0-60 times at 90%, 80%, 50%, and 25% SOC. The phone apps may not be as accurate as a vbox, but they're going to be close enough especially if your comparing the same device on the same car at different SOCs.