n2mb_racing
Active Member
I don't know. I did a max battery launch on my test drive.... It was likely a perfect launch.
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Pack Performance and Launch Mode Limits
- Thread starter Ingineer
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- Tesla Inc.
I don't know. I did a max battery launch on my test drive.... It was likely a perfect launch.
Note that Tesla communications were mentioning "powertrain" NOT "drivetrain".
Drive units are rated for a combined 568kW for 30 minutes (ECE R85, 375kW rear and 193kW front). This rating is based on thermal load and maximum allowable temperature that is defined by the class of motor insulation system. Launch of P90DL uses maximum of ~510kW for (conservatively) 15 seconds. So drive units can't be the limitation. Based on the above I believe that limiting are components of battery packs.
stopcrazypp
Well-Known Member
I know the power rating is higher, but that is based on the motor operating at a high efficiency rpm and load. Scaesare's point about low rpm torque (which I quote above) reminded me of that and brought an excellent point.
At low rpms approaching 0, the efficiency is much worse and there is a disproportionate amount of heat generated vs the power applied. Launch control is exactly that situation. You have to keep in mind that efficiency is not consistent throughout the rpm range.
Here's a induction motor efficiency chart just from a quick google:
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Stator winding temp rise is an interesting thought.
The other thought I had was the CV joints in the rear. Dropping max tourque on those things at a standstill to motivate a 5,000 lb. load to 60 in 2.5 seconds has got to be brutal.
Somewhere earlier in the thread something was mentioned about the counter being tied to having the large rear drive unit... that makes me wonder about the hard parts back there.
Of course only having the large rear unit would be the only way to draw max current from the pack... but it seems weird to make a reference to the drive unit if it's the pack being protected. I suspect it's not a pack protection thing...
If you are referring to the 10.999 car (Tesludi) on drag times, this is my car.
I did 6 runs, max battery, slip start. Fortunately I didn't do any runs with Launch Mode.
Times were from 10.991 to one run at 11.01. Did two 10.999's. Very consistent times.
After I ran these, I played with Launch Mode to get comfortable with using it. I had plans to try it out at the track, but now am not sure. I do not plan on racing on a regular basis, but had plans to keep this car a long time and it certainly would include some launches. Now I am not sure and I don't think I would have spent the 10K for Ludicrous if I would have known about the limitations.
You appear to again forget that Ludicrous was an option that cost $10k, on top of the $25k to $35k upcharge to step into a "Performance" Model S in the first place.
And you suggest we should just use launch mode "at my own risk?"
Sometimes your posts are well considered; this one is not.
St Charles
Tesla, not TSLA!
As a P90DL owner, I'm OK with this...as long as I know the terms of the agreement up front.
Walta
Member
I agree.
LM has been tested and compared to other launch techniques and didn't yield better results. So not using it is fine with me.
However if I find out that any method of launching is damaging the drive train over time and therefore power will be reduced? I would be very upset.
I emailed the SC and asked for that information. They responded that they will look into it. I will post that response when received.
Earlier today I tested a pedal smash with 90 percent SOC and max battery ready (MBR). Power tools recorded 505kw. I am running version 2.50.114 on a V3.
I have never used LM on this battery.
n2mb_racing
Active Member
Sounds like your battery is good. You would likely get 510+ at 100% soc.
Old Man Mike
Member
Congrats, that's right on the plotted max curve. If you get the chance, try cutting the Max Batt Pwr OFF after doing it with Max Batt Pwr ON and see if it matches the dashed plot.
FlatSix911
Porsche 918 Hybrid
The Porsche 918 Hybrid does not have a launch counter ... Porsche 918 Spyder - Wikipedia
The 918 Spyder is a mid-engined two-seater sports car designed by Michael Mauer. It is powered by a 4.6 litre V8 engine. The engine is built on the same architecture as the one used in the RS Spyder Le Mans Prototype racing car without any engine belts. In Car and Driver's independent test of the Porsche 918, C/D achieved 0-60 mph (97 km/h) in 2.2 seconds...
The engine weighs 135 kg according to Porsche and delivers 608 metric horsepower (447 kW) at 8,500 rpm and 528 N·m (389 lbf·ft) of maximum torque. This is supplemented by two electric motors delivering an additional 279 PS (205 kW). One 154 hp (115 kW) electric motor drives the rear wheels in parallel with the engine and also serves as the main generator. This motor and engine deliver power to the rear axle via a 7-speed gearbox coupled to Porsche's own PDK double-clutch system. The front 125 PS (92 kW) electric motor directly drives the front axle; an electric clutch decouples the motor when not in use. The total system delivers 887 PS (652 kW) and 1,280 N·m (940 lbf·ft) of torque.
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Walta
Member
Will do.
Tomorrow ish I will do another power tools run with a 90 SOC and MBR, then on the next run turn off MB and compare.
Somehow I missed post by @scaesare, until you mentioned it...I know the power rating is higher, but that is based on the motor operating at a high efficiency rpm and load. Scaesare's point about low rpm torque (which I quote above) reminded me of that and brought an excellent point.
At low rpms approaching 0, the efficiency is much worse and there is a disproportionate amount of heat generated vs the power applied. Launch control is exactly that situation. You have to keep in mind that efficiency is not consistent throughout the rpm range.
Here's a induction motor efficiency chart just from a quick google:
It is true that under locked rotor condition, when started across the line (without inverter) induction motor will experience high thermal load. The issue is not so much efficiency (it is actually zero, as no work is being done because speed is zero) but in the fact that locked rotor current is multiples of normal full load current (typically 6 - 8x), with the corresponding hot spot temperature shooting up very quickly, at much higher rate than when motor draws full load current. Normally as motor starting the slip goes from 1 in the locked rotor position to nominal, and current drops from locked rotor value to full load value, the heat load quickly reduces and hot spot temperature does not exceed critical value. For a launch mode, the rotor is held for up to 4 seconds, and if the motor would be fed across the normal AC source without inverter, the heat load would likely exceed critical and hot spot would shoot above maximum allowable.
However, MS/MX motors are started from an inverter which controls frequency and voltage/current fed to the motor to ultimately control motor torque (and current) to desirable value. Essentially drive motors are never exposed to situation when slip is equal to 1 and current equal to locked rotor current. In the launch mode, when rotors are kept at zero speed for up to 4 seconds, inverters feed them so that they just produce enough torque to take the slack out of the system. The losses in the motor and corresponding heat generated during the launch mode hold, as seen from this post are about 35kW, which is about 6% of the total kW rating of the front and rear motors. This means that losses and heat generated are roughly in line with normal full load losses. Since pre-loading in LM is limited to 4 seconds, and the whole launch at full power to about 15 seconds, and heat generated during 4 seconds of pre-loading is approximately equal or slightly higher than during operation at full load, the motors do not come close to their hot spot temperature corresponding to the 30 minutes ECE R85 rating.
To the point made by Scaesare, the mechanical loading during launch is also kept at check by controlling the torque to be just high enough to take the slack from the system.
So, in conclusion, the limiting component(s) for the LM are somewhere in battery pack, not drive units.
No, I haven't forgotten about that as I paid for Insane AND the Ludicrous retrofit for my car too.
Launch mode, was not even originally a part of Ludicrous. And as such, wasn't even included in the 10K price that many had already paid for Ludicrous long before launch mode even came out.
Launch mode, doesn't even come out until December of 2015. And not everyone with a Ludicrous car got it immediately after release.
Tesla Introduces 'Launch Mode' for Quicker Acceleration (Video).
The P90DL had been out long before that, and deposits for the P85D Ludicrous retrofit were being taken in September of 2015.
Launch mode, came well after purchase of Ludicrous cars and Ludicrous deposits for retrofit for many in here, and was not "refused" because at the time that we got it, there was no talk of having power cut as a result of using it.
I am compelled to ask though, did you not read what I wrote earlier about using launch mode at one's own risk?
Let me spell out what I meant by that as you don't seem to understand what I meant when I said that, and I will accept some responsibility for that.
IF....IF.......IF by giving us "launch mode", which arguably does nothing in terms of improving quarter mile times. Half will tell you that it does, the other half will tell you that it doesn't, but IF by giving us launch mode, it means that we will be subject to having our power cut.......well then wait for it......wait for it......wait for it........ THEN TESLA CAN KEEP LAUNCH MODE.
However IF I want launch mode..........which YOU seem to forget was not even originally a part of Ludicrous to begin with, and is actually of questionable practical value, well then IF taking it means that I must have my power cut, and I THINK that it is of value, and the price to pay for it is having my power cut after so many launches, well then I ought to have the option to use it at my own risk should I elect to have it added to my car after the fact, and I ought to be TOLD of that risk before I make a decision as to accept launch mode, or use it..
In other words, don't give it to me as a gift, and then months later and well after the fact, turn right back around and tell me that using this "gift" so many times is going to result in my being penalized by having my power cut. Thats not a "gift" at all. If that is the penalty to pay for using it, well then let me know up front. Not months later.
My comment was in line with what the gentleman from Rio de Janeiro eloquently and reasonably stated in an earlier post;
I don't know what your beef is with me. But I will tell you this straight up. I don't give a good damn what it is. So you may as well get used to my being here and posting up my opinions, same as any other member.
This.
And this.
And I am in total agreement with the positions above.
IF accepting the "gift" of Launch mode, which was NOT originally included with Ludicrous, if you remember, requires that I accept a risk of a decrease in my power at Tesla's discretion and based upon how many times I use it, well then tell me up front, and let me decide whether or not I want to accept that risk.
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lolachampcar
Well-Known Member
Perhaps it is time to modify the data logger to capture the BMS broadcasted max available current and max capacity messages (along with SoC and temperature which are already captured). I suspect people are going to want to know the state of their own battery and that of any car they are considering buying. The counter count is likely available via the diag screen thus likely broadcast as well. I'll toss a line out to the community to see if any has decoded these CAN frames.
St Charles
Tesla, not TSLA!
If you get some traction on this let me know. I have my own cable and OBD2 reader.
I'd like to add to my previous post.
This post above, is dead on and right on so many points.
First off something that the gentleman below doesn't seem to know, is that launch mode was given to people with P85D Insane cars too.
Cars which had been purchased long prior to launch mode being made "standard" in the version 7.0(2.9.40) update for cars as early as the P85D.
So to imply that he paid $10,000.00 for it is well, Ludicrous.
Arguably it was not sold to any of us as a stand alone feature.
Nobody consciously bought it and paid for it.
There was no increase in the $10,000.00 Ludicrous price for "launch mode" that they had already charged for and gotten from people for Ludicrous months earlier and which would have indicated that "launch mode" was extra.
They never charged pre existing P85D Insane owners a penny for it.
Rather it was given to existing and future owners of P85D, P90D in an update. Namely starting with 7.0(2.9.40).
It was bundled with an update. And in that update, nothing was said about cutting anyone's power were it to be used.
"Launch mode" is not a "stand alone" feature, not a stand alone option, that anyone in here paid extra for.
So don't imply that you've paid 10 grand for it.
Launch mode, as it stands right now, may well meet the classic, pre computer age definition of a "Trojan horse".
Something which is offered as a gift, a token of good faith, or show of good will, but which turns out to be anything but that and indeed the opposite of that.
You either seem to have forgotten or perhaps never knew, that launch mode was never an original part of Ludicrous and was given for free to many pre existing Ludicrous owners who had long already paid $10,000.00 for Ludicrous.
That it was also given free to pre existing owners of P85D Insane owners who had been in possession of their cars for nearly a year prior in some cases.
jbcarioca's point of it should have been "sold" with the disclaimer that using it could result in a power decrease, and if one wanted to buy it and use it in full awareness of that risk and tradeoff, then that is the way that it should have been handled.
I agree with him.
As it stands, we didn't get that chance. Tech_Guy didn't get that chance.
Instead Tesla left what appeared on the surface to have been a gift to him in his car. Same as the rest of us.
Only now, months later, we're told that use of this gift carries with it a risk that none of us signed on for.
We should have been told up front and if we wanted to take that risk i.e. have at it at our own risk, then fine. If not, well then it should not have been added to our cars, in some cases long after we had purchased them, without telling us of the caveats to begin with.
This post above, is dead on and right on so many points.
First off something that the gentleman below doesn't seem to know, is that launch mode was given to people with P85D Insane cars too.
Cars which had been purchased long prior to launch mode being made "standard" in the version 7.0(2.9.40) update for cars as early as the P85D.
So to imply that he paid $10,000.00 for it is well, Ludicrous.
Arguably it was not sold to any of us as a stand alone feature.
Nobody consciously bought it and paid for it.
There was no increase in the $10,000.00 Ludicrous price for "launch mode" that they had already charged for and gotten from people for Ludicrous months earlier and which would have indicated that "launch mode" was extra.
They never charged pre existing P85D Insane owners a penny for it.
Rather it was given to existing and future owners of P85D, P90D in an update. Namely starting with 7.0(2.9.40).
It was bundled with an update. And in that update, nothing was said about cutting anyone's power were it to be used.
"Launch mode" is not a "stand alone" feature, not a stand alone option, that anyone in here paid extra for.
So don't imply that you've paid 10 grand for it.
Launch mode, as it stands right now, may well meet the classic, pre computer age definition of a "Trojan horse".
Something which is offered as a gift, a token of good faith, or show of good will, but which turns out to be anything but that and indeed the opposite of that.
You either seem to have forgotten or perhaps never knew, that launch mode was never an original part of Ludicrous and was given for free to many pre existing Ludicrous owners who had long already paid $10,000.00 for Ludicrous.
That it was also given free to pre existing owners of P85D Insane owners who had been in possession of their cars for nearly a year prior in some cases.
jbcarioca's point of it should have been "sold" with the disclaimer that using it could result in a power decrease, and if one wanted to buy it and use it in full awareness of that risk and tradeoff, then that is the way that it should have been handled.
I agree with him.
As it stands, we didn't get that chance. Tech_Guy didn't get that chance.
Instead Tesla left what appeared on the surface to have been a gift to him in his car. Same as the rest of us.
Only now, months later, we're told that use of this gift carries with it a risk that none of us signed on for.
We should have been told up front and if we wanted to take that risk i.e. have at it at our own risk, then fine. If not, well then it should not have been added to our cars, in some cases long after we had purchased them, without telling us of the caveats to begin with.
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To be clear, I wasn't speaking about the partial torque load the mechanicals have to deal with during Launch Mode pre-load, it was the full torque load delivered during the launch itself.
Walta
Member
Did some MBR/MB off testing this morning.
Starting at around 30 MPH - and flooring it - I got
Starting at a 90 SOC Rated Miles 246
MBR 503kw
MB off 483kw
MBR 503kw
MB off 481kw
Ending at a 83 SOC
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