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

[brianman]

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.

Here's my version:

KEEP THE P85 ACCELERATION UNLIMITED until I decide to charge up! I don't need it to conserve power, this mode should be the advertised 416HP at ALL TIMES.

My car is nearly 2.5 years old and nothing has changed in this regard.

Sadly I don't hold much optimism that either vehicle will have this problem addressed.

I hold some hope that Tesla will at least talk about what's holding back a "pushed" P85 and a "battery below 50%" P85D. This would at least help the aftermarket know where to start looking for providing improvements once we get out of warranty and are willing to take more risks with 3rd party mods.

 

[brianman]

Took my P85D to a race track yesterday. Wasn't able to complete a single lap at full power (90% charged). Just a few corners and you're at 240kW. Push on and it will be less.

THANK YOU for sharing this information! I've been waiting for a P85D to report in on this. For comparison, my P85 drops to 160kW when that limiter kicks in. So at least the P85D represents a 50% improvement over the P85 in this regard.

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Excellent response. What you explain here is magnified 1,000% when driving a car like a P85D though- compared to a P85, which wasn't that drastic enough to make a complaint, ....

This post makes me think "he must be new here". We've (P85s, S85s, and even S60s) been complaining about this for a while.

 

[skilly]

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.

Its tough to put a substantial amount of 'wood behind the arrow' in terms of your reference to the P85D being a 0-60 car. It is but judging by the evidence on the 1/4 mile track it seems that the engineers designed its power curve around the 1/4 mark. Every car that it beats fairly (forget the Hellcat video - that's a joke), it shows that cars in the class would be equal to or greater than at that 1/4 finish line.

Here is a good example:
BMW 2014 M5 (roughly the same weight, and substantially less of a HP rating)
0-60 - 3.7sec
120.5mph @ 11.8sec

lets not forget the specs:
- 2 wheel drive
- 560HP
- 500ft # torque
- 4,400 lbs (close to P85D)

The P85D is about on par with a much faster 0-60, it starts backing off substantially about 2/3rds down the track. If you watch every youtube vid of it dragging other cars of those it beats, you can see the gap closing and it would be taken away just after the 1/4 mile mark. Maybe it was designed this way...the quarter mile is a good indictor of useful power in everyday driving (within reason).

 

[Danal]

The OP complaint about power reduction at 50% SOC is well taken. At some point near the end of the pack, it has to get less... but 50%????

Several have speculated about reasons for this, and one supposition is the pack itself is the limitation. "back of the envelope" math about the pack doesn't really support this:

SOC as a %:	100%	90%	80%	70%	60%	50%
Individual Cell Voltage (approx*):	4.1	4.05	4	3.9	3.8	3.75
Tesla Motors spec P85D: 671 HP/500KW:	500	500	500	500	500	500
Pack Voltage:	393.6	388.8	384	374.4	364.8	360
Amps at 500kW:	1270	1286	1302	1336	1371	1389
Parallel String Capacity, AH:	240.5	240.5	240.5	240.5	240.5	240.5
Discharge expressed as "C":	5.3	5.3	5.4	5.6	5.7	5.8
*No specs published on Tesla/Panasonic cells. These numbers are from other 'good' 18650s. They were also distorted downard to make "C" look worse, if anything. That's why 100% is not 4.2 (OK, 4.235 at 20C, don't nitpick).

"C" rating, the last row, is the ultimate limit for the pack supplying power. Not that much difference between 5.3 and 5.8 C, about a 9.5% change. Of course, they have to draw the line somewhere, but this seems like a rather fine line. We don't know their battery limit, but for those not familiar with LiIon chemistry in general, 5 or 6 are very low C numbers. Which no doubt helps ensure long cycle life. Still, they are pretty darn low; unlikely the pack is the limitation.

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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.

That was me, and I stand corrected. I agree with your numbers. I was in too much of a hurry and got a number out of my head. My point was there is a difference, be it 20% or 12%, marketing ensures the published number and physical reality are different. For all cars.

 

[krisg81]

The OP complaint about 50% is well taken. At some point near the end of the pack, it has to get less... but 50%????

Several have speculated about reasons for this, and one supposition is the pack itself is the limitation. "back of the envelope" math about the pack doesn't really support this:

SOC as a %:	100%	90%	80%	70%	60%	50%
Individual Cell Voltage (approx*):	4.1	4.05	4	3.9	3.8	3.75
Tesla Motors spec P85D: 671 HP/500KW:	500	500	500	500	500	500
Pack Voltage:	393.6	388.8	384	374.4	364.8	360
Amps at 500kW:	1270	1286	1302	1336	1371	1389
Parallel String Capacity, AH:	240.5	240.5	240.5	240.5	240.5	240.5
Discharge expressed as "C":	5.3	5.3	5.4	5.6	5.7	5.8
*No specs published on Tesla/Panasonic cells. These numbers are from other 'good' 18650s. They were also picked to make "C" look worse, if anything.

"C" rating, the last row, is the ultimate limit for the pack supplying power. Not that much difference between 5.3 and 5.8 C, about a 9.5% change. Of course, they have to draw the line somewhere, but this seems like a rather fine line. We don't know their battery limit, but we do know there are other similar batteries operating at 40 and 50 C, (with less cycle life). So probably not the pack being the limit... probably.

Thank you for posting this! I obviously have no factual/hard data to back my claim, but my "Seat of pants meter" feels a gigantic difference in performance at the 50% battery level. More than any ICE vehicle margins for hotter temps, bad gas, etc etc.. its a big difference.

Looking at the numbers it would seem that they are not showing the true reason for such performance degradation based on SOC.. something else has to be at play here. Also keep in mind I notice the power difference with no abusive driving, just some wide open/floored tests which even my wife said when doing this "Were you even floored that time??" Thats pretty bad when a passenger can notice the difference. Its big. Id say from 0-60 in 3.2 seconds to something like 0-60 in 4.5 seconds or so.

 

[Danal]

when a passenger can notice the difference. Its big. Id say from 0-60 in 3.2 seconds to something like 0-60 in 4.5 seconds or so.

Agreed. My "S85D on order, not yet received" neighbor noticed this from the passenger seat of my P85D when I punched yesterday at about 35% SOC. And he'd only test driven the local store's P85D once.

 

[30seconds]

jeez, what a discussion.

anyways besides HP loss to the wheels, environmental conditions, fuel,... seems that everyone is also forgetting that these comparisons are between a fixed geared vehicle and ones with 7 or 8 gears. For starters just look at a dyno curve for any ICE - HP is never a flat line - you have to get to peak (does it deserve an asterisk?) and then keep it there.

The Model S with a two or three speed transmission would pull even faster in the 1/4 mile.

And I'm pretty sure they never claimed it is a car built for a racetrack.

 

[MartinAustin]

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.

How about you get your cellphone out, take some videos of the speedometer and put them on Youtube for us? Under, say, 90% battery and 30% battery.

 

[brianman]

How about you get your cellphone out, take some videos of the speedometer and put them on Youtube for us? Under, say, 90% battery and 30% battery.

+1

I'd like to see them for educational purposes as well.

 

[AmpedRealtor]

So this thread is about Tesla falsely advertising the P85D because it doesn't live up to someone's expectation as a track car? I'm sorry, but where does Tesla sell this as a track car? It's marketed as a family sedan and nowhere does Tesla make any claims about its worthiness as a track car. I think any such expectations are in the mind of the beholder.

 

[krisg81]

How about you get your cellphone out, take some videos of the speedometer and put them on Youtube for us? Under, say, 90% battery and 30% battery.

I think I am going to try this with my GoPro soon - I wish I had a Vbox to properly test, and I am definitely not buying one for just this purpose lol

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So this thread is about Tesla falsely advertising the P85D because it doesn't live up to someone's expectation as a track car? I'm sorry, but where does Tesla sell this as a track car? It's marketed as a family sedan and nowhere does Tesla make any claims about its worthiness as a track car. I think any such expectations are in the mind of the beholder.

Hey Amped!

This discussion has really nothing to do with the P85D being a track vehicle, for which it is not and not why someone would purchase it, or expect it to be anything close to a track car.

This is about the car performing with the amount of horsepower it is advertised at, which it does not based on the amount of battery charge. Kind of like your iPhone running fast on a full charge, but slows down tremendously at 50% and lower battery levels.

 

[skilly]

How about you get your cellphone out, take some videos of the speedometer and put them on Youtube for us? Under, say, 90% battery and 30% battery.

you didn't say please but Im sure you meant to...

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So this thread is about Tesla falsely advertising the P85D because it doesn't live up to someone's expectation as a track car? I'm sorry, but where does Tesla sell this as a track car? It's marketed as a family sedan and nowhere does Tesla make any claims about its worthiness as a track car. I think any such expectations are in the mind of the beholder.

come on. That's not a fair statement. There are some references to track but really that's just where the observations are being made. Don't let that detract from the point which is that insane mode is short lived and the reference to HP is highly suspect. No one has claimed it to be a track car, nor has anyone even been negative about the car itself. Really if I had to summarize this thread its about a quest for the truth in the claims around insane mode, HP, and the general performance expectations one would expect from the claims.

 

[sorka]

So this thread is about Tesla falsely advertising the P85D because it doesn't live up to someone's expectation as a track car? I'm sorry, but where does Tesla sell this as a track car? It's marketed as a family sedan and nowhere does Tesla make any claims about its worthiness as a track car. I think any such expectations are in the mind of the beholder.

No he's simply saying that the car doesn't make 691 hp which it doesn't. On the other hand it makes way more torque than promised at least at launch.

 

[stephenpace]

1) I agree with the point being made above about insane mode being greyed out below 50% charge. It could even have a nice explanation of why in a button next to it.
2) Off topic, I attended an event two weekends ago with a Hellcat and the driver said that at full blast using the red key on a track you have about 13 minutes of fuel before you hit empty. The car is a beast and drinks fuel on the track like any gas car does at that speed. (Not trying to minimize the 'reduce power' mode issues, and I realize the Hellcat can refill faster than I could, even if there were portable SuperChargers at the track like Tesla brought for Refuel.)

 

[krisg81]

come on. That's not a fair statement. There are some references to track but really that's just where the observations are being made. Don't let that detract from the point which is that insane mode is short lived and the reference to HP is highly suspect. No one has claimed it to be a track car, nor has anyone even been negative about the car itself. Really if I had to summarize this thread its about a quest for the truth in the claims around insane mode, HP, and the general performance expectations one would expect from the claims.

Very true- I think amongst all this debate is one common denominator: We love this car. I love the Model S so much I traded in my P85 not for a competitive vehicle (is there even one out there that offers such a total package anyway) for a P85D. I think it is just me being disappointed a bit going from a P85 to the P85D and realizing it is only faster for a small portion of the time before the battery gets lower and that really sucks. I wish the Insane mode would stay Insane for longer than 100 miles of range. Maybe by raising the questions Elon and the Tesla engineers will give answers or improve this over time as they learn the dual motor configuration better.

So yes, this is a quest for truth and to validate the 691HP claims and have a friendly discussion of why there is such a dramatic drop off of power from the Insane mode vs. the S85/P85 cars. I know the car is already so perfect and I am nit picking, but remember- the reason certain people drop this kind of money on the top dog P85D version is because they are performance enthusiasts who want every drop of horsepower they paid for.. and thats me.. I have been that way since a kid

 

[Ldub22]

Kris,

I want to know the answer to this too, as a guy who ditched his Porsche and is waiting on his P85D with bated breath. But the bigger question is: is this a SOFTWARE issue, or a PHYSICAL LIMITATION issue. i.e., can it be addressed in the future or are we stuck with it until they build a better car? Is this why Tesla ditched the roadster concept and doesn't make a halo sports car? Theoretically, you could stuff batteries in a shorter wheelbase carbon fiber tub and build a Tesla sports car that would have the performance envelope of an open-wheel car -- or could you? Maybe the battery technology could not handle that?

 

[EarlyAdopter]

Wow, so much speculation and so little data on this thread.

1. Forget any "butt dyno" or "it feels to me" impact on SOC to acceleration. That's terribly anecdotal. Let's see some real data from a vbox or equivalent high precision data logger for 0-60 runs at 90% vs. 30%.
2. As for power limiting kicking in at low SOC, I did two 0-60 runs yesterday at 13% SOC in my P85D after driving 100 miles on the highway and tracking the car before that and did not have any dotted line yellow limiter show up on my dash. So that's not it.
3. As for power limiting kicking in on the P85D during track driving, I took mine to the track yesterday and didn't experience power limiting kicking in once. That said, it was a new track for me so I wasn't pressing it as hard as I could, but I was still hammering it full throttle up to 120mph on the main straight and didn't see the limiter once. Each 20 minute-ish session was 20 miles total during which I consumed 20kWh, so I was running at an average of 1000Wh/mi. I did 4 sessions. Not exactly going easy on the car. It was 45-50F outside and wet, so maybe outside temperature is a factor.

All in all, I have to say I'm actually pleasantly surprised at how well my P85D did as a track car. I missed my old tricked out Audi S4, and my old P85 just didn't do it. The P85D does. I miss the S4 no longer.

 

[supratachophobia]

Could you elaborate? With numbers?

No, I can't. None of us can because all we have to go on are botched dyno runs, a seemingly arbitrary dotted line, and HP numbers that don't add up to the KW numbers.

Don't get me wrong, I'm not mad. I'm just surprised that it took as long as six months of real world experiance to show that performance takes a dive drastically when you try to pull that much juice out of the battery at once. I mean, if the P85 is doing some sort of protection mode with the battery being equal, why would we not think the dual motors would exacerbate the issue?

I've never understood the track argument though either. I can't think of a real world driving situation where those same requests of the car would be duplicated. What I do care about is multiple overtakes at city and highway speeds, repeated as needed, in hot weather if that's the case. As long as that is not hindered and can be sustained for that top 80% SOC, I have no qualms. But we are all different and as they say, your mileage may vary regarding your demands on the car.

 

[qwertzy]

Kris,

I want to know the answer to this too, as a guy who ditched his Porsche and is waiting on his P85D with bated breath. But the bigger question is: is this a SOFTWARE issue, or a PHYSICAL LIMITATION issue. i.e., can it be addressed in the future or are we stuck with it until they build a better car? Is this why Tesla ditched the roadster concept and doesn't make a halo sports car? Theoretically, you could stuff batteries in a shorter wheelbase carbon fiber tub and build a Tesla sports car that would have the performance envelope of an open-wheel car -- or could you? Maybe the battery technology could not handle that?

Lithium ion batteries have fade free power, its the same from full to zero, so this is a software limitation. Probably for battery longevity.

The battery platform makes the cars upgradable for a power density power pack like the Rimac batteries. I'm not sure if they'll make one but I know they will upgrade the battery much easier than the Roadster 3.0 package. Also the car hasn't gotten all its performance updates so we don't know what its full performance is.

 

[William13]

I think the emphasis is and should be on street performance characteristics. The car passes better than other cars due to instantaneous response. This is in spite of lacking a gut retching delayed downshift and acceleration from a 55 mph start. The car starts from a red light or stop sign quicker than everyone else. Esp 0-35 mph.

I expect the lack of trust in the horsepower rating is due to a lack of subjective accounting for the single gear ratio. Figure out how to measure it accurately, measure several cars in first gear, post your findings.

Tesla guarantees the battery pack and thus limits power. No duh. Does anyone else guarantee their engine for non street use? Tesla is cautious for good reason.

I await a true modification which is track worthy. This is likely two pack improvements away from today.