Yes, but when they measured 864lbs that was from all 4 wheels, and thats where they got the reading of 420HP peak. The torque is there- but the horsepower isn't, which makes sense of why an S85/P85 and P85D feel like they have the same horsepower after 60-70MPH. Those 691 horses are only available for 0-60 runs, and after that- they just aren't there.
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[updated with *] P85D 691HP should have an asterisk * next to it.. "Up to 691HP"
- Thread starter krisg81
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Yes, but when they measured 864lbs that was from all 4 wheels, and thats where they got the reading of 420HP peak. The torque is there- but the horsepower isn't, which makes sense of why an S85/P85 and P85D feel like they have the same horsepower after 60-70MPH. Those 691 horses are only available for 0-60 runs, and after that- they just aren't there.
Danal
electricmotorglider.com
I put my car back together tonight and made a couple of quick runs. 53% SOC. Power meter went to just below 480, as in video above. I STAND CORRECTED. I have NOT seen 500+. I just assumed it in my peripheral vision. Finding a safe empty road, and looking right at it, absolutely below 480.
90% or so SOC runs in a few hours.
Just thought of this:
In the video of Insane vs. Sport mode, both modes hit the same kW output, which is a little under ~480kW.
But there is a 1 second difference or so in both modes. The only difference being a slower ramp up until full ~480kW power in Sport mode.
With this said, the ramping to full power does significantly affect performance of the P85D, and as SOC levels diminish, the ramping to full power also slows down, resulting in lower performance of the car. Not sure what the physical limitations are that's causing this, or it's just software limiting power like Sport mode in order to conserve battery levels. Something just doesn't seem right. What ever code allows a variance in power in Sport mode seems to be at play below 50% SOC, regardless of Insane mode being enabled. I guess I'm just rambling and trying to come up with anything that may give me hope this is fixable via software and not a physical limitation of the car.
Slower power rampup indicates lower torque that is a result of lower motor current. This in turn indicates the motors are heating up. It may very well be that computer just thinks they should be heating up based on history data and lowers max current to them
If batery was the limitation, the rampup speed would be the same, it would just end at lower max power.
Cooling electric motors is sitll unsolved problem. They are able to remove about 7kW of heat on continous basis, that suffices for those 69kw of continous power. Anything more needs periods of lower power to remove acumiulated heat from the rotors.
there is a simple solution to this overheating problem: don.t ever offer more than continous power. No overheating problem but one miserable car to drive and own.
If batery was the limitation, the rampup speed would be the same, it would just end at lower max power.
Cooling electric motors is sitll unsolved problem. They are able to remove about 7kW of heat on continous basis, that suffices for those 69kw of continous power. Anything more needs periods of lower power to remove acumiulated heat from the rotors.
there is a simple solution to this overheating problem: don.t ever offer more than continous power. No overheating problem but one miserable car to drive and own.
Claiming it the fastest Sedan and labeling the product as a performance car which actually isn't able to complete a lap with full power.
Only Fanboy will defend that.
BTW, I have a p85+ and ordered a P85d. I am also very disappointed by the fact that my P85+ isn't able to hold up the speed pass 160+ kph.
Only Fanboy will defend that.
BTW, I have a p85+ and ordered a P85d. I am also very disappointed by the fact that my P85+ isn't able to hold up the speed pass 160+ kph.
thegruf
Active Member
It is quite possible to argue that variable power can also be a safety risk. If you expect full performance and only get part performance, then you wont get to where you expect to be, when you expect to be there. Granted these are high powers but the principle still applies.
I think three things are required.
1. Depending on the outcome of the trials discussed above by others, you may need to get your car checked out.
2. TM I think should publish some information about this. Reasonable people will understand this in a reasonable way (it is a road car with exceptional power for internittent use), unfortunately there will also be hysteria which is probably deterring TM from doing so.
3. TM should enhance the software for the power display to indicate when only reduced power is available. Then the driver is informed and can make decisions accordingly.
If TM fail to do this, it is not inconceivable that somebody will go after them legally for misrepresentation, which is in nobody's interest.
I am satisfied with the indication of power limit provided. I have seen the yellow dashed line appear not only when car is overheating, but also when SOC is <~10% while not even trying to drive fast.
We had a great wave of articles about 691hp hypercar performance. As a shareholder I really wouldn't like a wave of "Tesla's supercar actually delivers 69kW/100hp. Customer demands refund in court". They should be more clear about it.
There seems to be a lot of ignorance in this thread on how the basics actually work...
I mean, not to be an a******e, but I'll point out a few things that should be obvious.
Could go on and on, but the total power possible from the "engine" in the P85D is 691 HP. Whether or not the engine can be run at that power level remains to be seen.
I mean, not to be an a******e, but I'll point out a few things that should be obvious.
- First, a battery pack with more charge can put out more power. A battery pack with less charge can put out less power.
- Why? The limiting factor is amperage. The physical conductors can only safely handle so much amperage.
- A fully charged 85kWh pack will sit around 400VDC. So, a 20 kW draw will result in about a 50A load.
- At ~10% SoC the voltage is about 310VDC. That same 20kW cruising draw will need ~65A now.
- Apply this to the P85D
- Let's say 450kW is the number. Fully charged, not even taking sag into account, that'd be a 1,125A draw...
- At 50% SoC the pack voltage is about 350V. 450kW would need 1,285A now.
- At 10% SoC we're talking a demand of 1,450A for 450kW.
- The inverters will have a maximum operating amperage, which will effectively limit maximum power (kW) at lower voltages/SoC.
- This is more pronounced in the P85D since ~450kW is more than a 5C power draw from the cells.
- This is pretty tough on them to begin with, let alone at a lower SoC where the cells would need to put out even higher amperage.
- A cold battery pack puts out less power. A hot battery pack can put out more power.
- High demand or high charge at either temperature extreme is stressful on the cells and will cause degradation
- Regen and power limits are to ensure the longevity of the pack in temperature cases
- At high states of charge the maximum input power possible is lower. At low SoC it is higher.
- Even if a huge amount of power were presented to the cells, they would only absorb so much due to a high state of charge.
- Hence the reason for the max regen limit at high SoC
- Applies to the supercharger taper
- It is possible that the 85kWh battery pack is not capable of the ~520kW output needed for 691 HP.
- This would be > 6C power draw.
- Even at 100% charge, this would be pulling nearly 18A through each hair-thin cell level fuse in the pack.
- For contrast, wire rated for this is ~2mm diameter. The cell level fuses are something like 0.2mm (don't know exactly, but they're tiny).
- If one of these fuses blows the pack loses 1/74th of total capacity (1.3%) immediately due to an irrecoverable out-of-balance issue.
- Speculation: I'd assume the "DUAL MTR" branded packs have heavier cell fuses.
- Speculation: In the dual motor setup, simultaneous full HP output may not be possible.
Could go on and on, but the total power possible from the "engine" in the P85D is 691 HP. Whether or not the engine can be run at that power level remains to be seen.
Danal
electricmotorglider.com
All you say is true in detail... in fact, I put up the table of numbers about V/A/C at various State of Charge. Couldn't agree with you more. At the same time, it misses the key that triggered this whole thread:
The widely touted advertising claim is 691HP. Which is right at 500kW. No one has seen that, ever, under any combination of SOC, Temperature, Cold motors, Hot Motors, Cold Pack, Hot pack... take every one of your data points at set it at its 'perfect' setting... and we still don't see the power advertised.
What we DO see is 3.2, and quite frequently 3.1, seconds 0 to 60. We see that all the time, even at "less than perfect" points for battery/motor/etc.
I, for one, am VERY HAPPY pulling the blood out of other people's toes!
This again. The thread is about not seeing 691hp at any point under any conditions even though a reasonable person would see the number in advertising and draw a logical conclusion.
My surprise still comes from the fact we've had almost 5 months of at least the raw data from kW under acceleration and then real world experience added to it, and three years of data from the P85 that shares a battery, one motor, and inverter. Why did no one see this earlier? Of all the communities that could see through the foggy claims of 691hp, especially with the testing fervor I've seen here with charge rates, acceleration, battery degradation, etc., I would have thought this one would.
We've established that 691 is not a real world number but 3.1 0-60 is phenomenal. Now back to OP, is there an issue with his car or is there a legitimate concern with the P85D having only enough pulling power to get on there consecutive freeway entrances before HP drops to xxxHP? And is SOC a factor in consecutive accelerations (non track) where the driver would assume that merging would take X seconds, but it might take X times 2? Thereby posing a possible safety issue by misjudging the cars performance.
The power output meter on the instrument display is not a perfect, precision read-out. It's a consumer-level gauge! Tesla can modify the visualization any way it wants -- if it wants to display 600 kW, it can do it just by changing the numbers on the dial. You can't really trust it for anything in diagnosis. Until someone puts current loops on the motor leads with a high-resolution data recorder, you won't be able to say anything definitively.
I see the same thing when the car throttles its charging rate; some will offer up that because the Tesla never showed below 230V, there is no way that they could have voltage fluctuation. That's ignorant at best, disingenuous at worst.
What wk057 said is spot-on. Basic physics combined with knowledge of the cable sizes used tell us that extracting high-power output at a much lower voltage places a bigger stress on the system. I agree that it's highly unlikely that we'll see any EV that can sustain 700 HP across the entire range of SOC, unless it's massively overbuilt - and then be prepared for motor power cables that are the size of your arm. So yes, Tesla is playing loose with the 691 HP term. Then again, if you're realistically expecting 691 HP throughout the entire SOC range, then you probably have purchased the wrong car, at least for the purpose you'd need it for.
Bragging rights? Ok. All I know is the end result is amazing, and far exceeds my expectations compared to what we're used to.
I see the same thing when the car throttles its charging rate; some will offer up that because the Tesla never showed below 230V, there is no way that they could have voltage fluctuation. That's ignorant at best, disingenuous at worst.
What wk057 said is spot-on. Basic physics combined with knowledge of the cable sizes used tell us that extracting high-power output at a much lower voltage places a bigger stress on the system. I agree that it's highly unlikely that we'll see any EV that can sustain 700 HP across the entire range of SOC, unless it's massively overbuilt - and then be prepared for motor power cables that are the size of your arm. So yes, Tesla is playing loose with the 691 HP term. Then again, if you're realistically expecting 691 HP throughout the entire SOC range, then you probably have purchased the wrong car, at least for the purpose you'd need it for.
Bragging rights? Ok. All I know is the end result is amazing, and far exceeds my expectations compared to what we're used to.
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This is all true, but the voltage between an SOC of 90% and 20% is relatively small. Too small to account for the supposed massive drop in acceleration that some are reporting. Yet others are saying they don't see a big drop in performance which is what you would expect if there wasn't an intentional software limit.
I suspect the P85D has never made the claimed power yet it's faster than you would expect if that is true because the power curve is so wide. How fast you can accelerate is not just related to peak power but how much power you put under the curve on the way to that peak power and electric motors are the master at that as they produce constant torque starting at 0 RPMs.
I suspect the P85D has never made the claimed power yet it's faster than you would expect if that is true because the power curve is so wide. How fast you can accelerate is not just related to peak power but how much power you put under the curve on the way to that peak power and electric motors are the master at that as they produce constant torque starting at 0 RPMs.
This thread is so huge... Someone might have already pointed this out.
But on Internal Combustion Engines, the advertised HP is Peak HP. Which for most Gasoline Engines, happens right at or near redline. The Tesla engines have the benefit of all the power being available from standstill, vs winding out a gasoline engine. Most people would prefer to have it all at the beginning.
But on Internal Combustion Engines, the advertised HP is Peak HP. Which for most Gasoline Engines, happens right at or near redline. The Tesla engines have the benefit of all the power being available from standstill, vs winding out a gasoline engine. Most people would prefer to have it all at the beginning.
Lithium ion batteries have fairly flat discharge curves. From 80% to 20% soc there's about an 8% drop in voltage. I'll be happy if:
1) At 80% SOC, because this is what Tesla says we should normally charge to for regular daily driving, I can get the 3.2 second 0-60 that we've seen.
2) At 20% SOC, the power is reduced but only by about 8 to 10%.
If all else is equal in terms of temperature of the battery, the motors, etc and there's a massive drop in power below 50% SOC, I'm going to be pretty pissed. If there's a little drop in performance, then I'll be fine with it.
I would say it isn't "Massive" at 50%, but thats when you start to feel the Insane mode not working anymore, and it seems to perform at Sport mode. The problem is, from there, it goes downhill very quickly. 40% is much worse, 30% even slower, 20% is just laughable to me compared to a full charge- yet the Insane mode stays lit up even though clearly its operating slower than Sport mode.
I would love for the OS of the car to just be more transparent if this is a physical issue that can't be remediated via software updates- I am totally fine with that. Clearly define when the car can no longer perform at Insane levels, grey it out below 50% and force Sport mode, and below 30% have an Eco mode. One of my points of creating this thread was pointing out "Advertised horsepower claims". I am completely happy with its performance when fully charged- I wish it could keep that performance up throughout the SOC range.. but it can't. If the computer would clearly state this and display what is going on the me, the driver- I would better understand this and not feel like Tesla is getting over on us with a brilliant marketing campaign and hyped up horsepower numbers, because that HP claim is very short lived.
What we have been doing with the car to maintain peak performance (Once again, NOT HEAT RELATED Mr. "WarpedOne") is just charge the battery closer to 95% each day. Since the car is driven around 60-70 miles per day, that keeps the SOC level where the car always feels as peppy as possible, and if a friend stops by that night before the car is fully charged it still has plenty of power to go for a test drive with most horses on tap still
Its those longer trips you get under 50% battery and it sucks. But like i said, the workaround for us is just starting with a higher SOC level every day.
Yes, we know that's happening to yours and maybe one other for sure. I think we're still waiting for data from others. i.e. vbox runs at various lower SOCs.
3.2 seconds to 4.2 seconds 0-60 is a *massive* difference in performance. About a 40% reduction in hp. I would accept a 10% reduction at 20% vs 80%.
Really hoping that this upcoming 6.2 update is going to address this if it turns out this is actually an issue with all the P85Ds currently.
3.2 seconds to 4.2 seconds 0-60 is a *massive* difference in performance. About a 40% reduction in hp. I would accept a 10% reduction at 20% vs 80%.
Really hoping that this upcoming 6.2 update is going to address this if it turns out this is actually an issue with all the P85Ds currently.
I think that Elon even mentioning an inverter update on Twitter is interesting- I am sure they are still working out tweaking performance with this new dual motor setup and I'd even go as far as saying that they realize that its not living up to its advertised HP rating, especially consistently. I am confident this can be resolved via software, and its not hardware related as many people seem to jump to the conclusion w/ battery specs, voltage, etc as if they engineered the hardware in the car. I think Tesla can fix this with an OTA update, at least I'm hoping.
stopcrazypp
Well-Known Member
There's two things being mixed up. First of all it is claimed here that the P85D never hits 691 hp, but rather makes around 400 hp (similar to P85+). This supposedly is already sufficient for a 3.2 second 0-60 based purely on higher low end torque (and not power). A proper measure of this would be an AWD dyno that can take the full torque of the Model S without slipping (the only dyno test so far, the people had to ease things in).
Second is that the 4.2 second 0-60 mph claim is by loco under pretty much all SOCs. It had nothing to do with SOC. That number has purely to do with his specific car/test conditions. 62-124mph is where he noticed a difference (based on temperature, not SOC).
http://www.teslamotorsclub.com/show...o-691HP/page12?p=949441&viewfull=1#post949441
So far we don't have any data supporting that the car is significantly slower at lower SOCs (by significantly I means variance of more than the 0.1-0.3 seconds that might be common), other than that it feels that way. Others are working on gathering that data.
There's no world in this universe where an MS could have an exit speed of 115 in the 1/4 with only 400 hp given it's 2.5 ton weight. Trap speed will be determined by hp, not torque. Trap time will be effected by torque.
A stock C7 with 460 hp is a 12.2 second car vs 11.7 on P85D both having about the same trap speed yet the P85D weighs almost 1500 lbs more.
Agree with everything else.
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