Pack Performance and Launch Mode Limits

[AWDtsla]

You know, if I knew ahead of time that TSLA would buy SCTY, I never, ever would have bought TSLA.
Would save me about 100x Ludicrous fee. And that after year of BS with Model X ramp.
This moral outrage is funny compared with other misleading communication they've done...

There are no guarantees in investing. However there are many laws protecting consumer transactions, stronger in some countries than others, i.e. Norway.

 

[JRP3]

Just to add a little more to the conversation for the people siding with tesla here. Two of the service centers I called sounded like they sincerely have never heard of any kind of counter or limitations on L models. Basically when I asked about it they said along the lines of "I'm sure tesla would never do that" because they thought that limiting power under any circumstance permanantly would be ridiculous and unfair.

Even Tesla employees know it's wrong, yet bhzmark thinks owners should be fine with it

 

[bhzmark]

Even Tesla employees know it's wrong, yet bhzmark thinks owners should be fine with it

Your use of "it" fails to refer to anything specific.

And actually it isn't that the Tesla employees "know it's wrong", it's that they likely suspect, as I do, that your fear isn't justified, and that the facts will show a more reasonable engineering design as well as remedy for any extraordinary usage.

I am fine with engineering trade-offs in general as a concept -- including those implemented through software rather than hardware and including those based on calculated stress and fatigue based on usage events to preserve longevity and reduce failures.

My outrage depends on facts and evidence and specifics. There arent sufficient specifics yet to justify outrage and given the huge numbers of PL owners out there launching and WOTing their cars all the time, and a grand total of now two people showing (still unconfirmed by specific documentation) power limits.

With only those facts, especially the TRC cars, this doesn't appear to be a big deal. Maybe it will be once more facts come in or as time passes revealing many many more to hit some limit from relatively ordinary use but I reserve my outrage for more evidence and facts and especially real demonstration of harm and injury and costs to many owners.

 

[bhzmark]

Here let me help you defend yourself

Gifs are a poor substitute for providing more relevant info.

How many launch mode launches? Approximately?

 

[JRP3]

I am fine with engineering trade-offs in general as a concept -- including those implemented through software rather than hardware and including those based on calculated stress and fatigue based on usage events to preserve longevity and reduce failures.

Yup, that's fine, if it's noted at the time of sale. Though the proper engineering would be to build components capable of handling the power the vehicle is designed to put out.

My outrage depends on facts and evidence and specifics.

Apparently not.

 

[FlatSix911]

Already started looking at the Porsche 911 Turbo S to replace my S when my lease is up. Should be as fast as the P100D.

Not so fast ... Porsche also has a launch mode counter and will refuse warranty claims for hitting the rev limiter too many times

 

[bhzmark]

To be fair, I am an automotive engineer, and I have extensive experience in electric powertrains. Unless there is a design error there is no reason for this limitation. You'll note the non-P models are sufficiently-designed to not need this.

Was it a "design error"? Or a design trade-off? How can you tell the difference?

I just see the hardware design (of maximum discharge events accelerating the stress and fatigue of the powertrain) and it's mitigating software design (of reducing the damage caused by maximum discharge events after the component has a calculated age and stress exposure) as all engineering trade-offs. And given the current information, I'm not ready to second guess Tesla engineers on those trade-off strategies. Especially if I plan on keeping my car past the warranty period.

 

[n2mb_racing]

Not so fast ... Porsche also has a launch mode counter and will refuse warranty claims for hitting the rev limiter too many times

Isn't it auto? How do you bang into the Rev limiter anyway? It's a pdk transmission, right?

 

[FlatSix911]

Isn't it auto? How do you bang into the Rev limiter anyway? It's a pdk transmission, right?

PDK allows manual shifting and records all revs over redline in 6 categories monitored by dealers at the time of service.
Failures and Warranty claims are often denied. More details here: Porsche Rev range activity guide from 911virgin

Rev Range Activity....a much discussed and often misunderstood topic striking fear in to the hearts of those exploring Porsche ownership or those looking to renew or activate insurance backed warranty schemes on their vehicles. We embraced the importance of Rev Range activity many years ago and our contribution towards a universal clarity has been significant.

Engines are designed to operate up to a maximum rotational speed. The manufacturer uses a rev limiter to prevent engine speeds exceeding a pre-determined point of safety. At full throttle and whilst pushing and holding the accelerator pedal down indefinitely the engine can’t and won’t exceed the rotational speed of the limiter. However, when a driver selects too low a gear relative to the speed of travel, the momentum of the car can mechanically drive the engine past a point of safety.

 

[AWDtsla]

PDK allows manual shifting and records all revs over redline in 6 categories monitored by dealers at the time of service.
Failures and Warranty claims are often denied. More details here: Porsche Rev range activity guide from 911virgin

Like I said probably dozens of pages ago, this is not the same thing as Tesla has done. It is not even close. Just the presence of "counters" does not make things equivalent, not unless you're drinking the Tesla kool-aid. One would already assume there are counters for every action taken, even a histogram of the battery discharge energy vs current.

The most interesting thing about Porsche's counters is that if the engine has operated for 50 hours or 200 hours respectively since the last rev count, it's considered to be OK again, since that's proof exceeding the rev limiter didn't break something. Which could also be followed up by a compression test.

Frankly, I don't see anything wrong with those counters. So you're going to mis-shift, rev like 3 grand over the rev limit, then take it into Porsche for a warranty claim? Yeah, no.

Compare to Tesla's counters: do the thing we told you to do and the reason you bought the car for, we'll make some mysteriously triggered counters of you doing those things because our car can't actually do what we said, then we're going to remove that ability outright, forever. edit - We already have your money, what are you going to do about it?

 

[vgrinshpun]

vgrinshpun,
The problem is most likely thermal cyclic fatigue of the per cell interconnect wires. Note the P100's change to a flex circuit. Also note that the BMS is doing the counting and the BMS broadcast max permissible current is what is being reduced.

The electrical systems can roughly be separated into current carrying (metal) and dielectric (insulating materials) components. As far as thermal cycling fatigue is concerned, the threshold of thermal stress that has potential of reducing expected life span of insulating materials is much lower then current carrying components. This is the reason that components that dictate limiting current (and power) have to be insulating materials, NOT current carrying parts (interconnect wires, etc.)

What is counterintuitive for engineers (and likely anyone else) is trying to make sense of your last sentence.

It is very easy for an engineer to say "no, not possible" to a request of extracting more performance form the system which has continuous rating that is dwarfed by the low duration peak rating. Responding "let me see what can be done" and taking on a such task requires very careful, diligent and sophisticated optimization and overall higher level of engineering talent.

 

[AWDtsla]

It is very easy for an engineer to say "no, not possible" to a request of extracting more performance form the system which has continuous rating that is dwarfed by the low duration peak rating. Responding "let me see what can be done" and taking on a such task requires very careful, diligent and sophisticated optimization and overall higher level of engineering talent.

Duty cycle is a simple and straightforward engineering concept. It's not some magic that Tesla invented.

 

[vip gts]

PDK allows manual shifting and records all revs over redline in 6 categories monitored by dealers at the time of service.
Failures and Warranty claims are often denied. More details here: Porsche Rev range activity guide from 911virgin

This is known to Porsche owners and can be avoided.
Problem with this Tesla counter is we were not told how to avoid it.

 

[vgrinshpun]

You should stop dishing out on poor "wire bonds" engineering. Even if they are the problem (although from technical point of view it is highly unlikely - this is probably case of SC technician opining about subject he/she does not fully understand - knowing enough to be dangerous) it (problem) is NOT in poor engineering - it is inherent.

It is counterintuitive for non-electrical engineers, but problem with the counters and extracting maximum amount of power for short duration of time from the powertrain that is rated around 69kW continuous duty is not in poor engineering, but in engineering that was excessively sophisticated...

In the end, it doesn't really matter what the specifics are.

I agree, and that is why it is so strange to me that you keep bringing this up. They screwed up with not providing clear disclaimers for the way counters are operating. As we agree that this IS the problem, why do you feel necessary to (repeatedly and undeservedly) trash their engineering?

They should have done the engineering to estimate cycle life, and THEN put the pack/drivetrain through a rapid cycling test in the lab to determine if the warranty costs were acceptable before a single unit shipped to a paying customer.

What they actually did was give the hardware to customers, and treat them as the science experiment.

I believe you have it backwards. They designed the system with built in opportunities of increasing performance in future steps, balancing it against long time health of the powertrain and limiting risk of catastrophic failure. The failure as in dielectric (insulating materials) failure - and contrary to the often repeated speculation that counters are needed to reduce warranty expenses, failure of insulating materials is a SAFETY issue. If you want a taste of what is at stake and don't mind watching gory videos, google "arc flash videos".

Adding this additional performance as laid out in conceptual plan required further detailed engineering which was carried out in steps and lead to eventual introduction of ludicrous and launch mode.

Once again, the core of the issue here is Tesla screwing up timely release of the proper disclaimers, so I am at loss explaining your urge for repeated attacks on perceived inferior engineering.

 

[vgrinshpun]

Duty cycle is a simple and straightforward engineering concept. It's not some magic that Tesla invented.

The concept is straight forward, applying it to the complex systems without prior multi decade history is not. Tesla DID come up with the system not offered by anyone else.

 

[Andyw2100]

Tesla DID come up with the system not offered by anyone else.

And then started taking pieces of it away.

 

[vgrinshpun]

And then started taking pieces of it away.

Nice try, not going to spend my time with detailed response to pot shots.

 

[AWDtsla]

The concept is straight forward, applying it to the complex systems without prior multi decade history is not.

It is.

Tesla DID come up with the system not offered by anyone else.

They did not invent some new science or engineering, only the will to integrate these systems into a product, opportunistically timed when the energy density of lithium ion made it possible to deliver a compelling product.

 

[hostman]

Your use of "it" fails to refer to anything specific.

And actually it isn't that the Tesla employees "know it's wrong", it's that they likely suspect, as I do, that your fear isn't justified, and that the facts will show a more reasonable engineering design as well as remedy for any extraordinary usage.

I am fine with engineering trade-offs in general as a concept -- including those implemented through software rather than hardware and including those based on calculated stress and fatigue based on usage events to preserve longevity and reduce failures.

My outrage depends on facts and evidence and specifics. There arent sufficient specifics yet to justify outrage and given the huge numbers of PL owners out there launching and WOTing their cars all the time, and a grand total of now two people showing (still unconfirmed by specific documentation) power limits.

With only those facts, especially the TRC cars, this doesn't appear to be a big deal. Maybe it will be once more facts come in or as time passes revealing many many more to hit some limit from relatively ordinary use but I reserve my outrage for more evidence and facts and especially real demonstration of harm and injury and costs to many owners.

UNCONFIRMED BY SPECIFIC DOCUMENTATION? WHAT? IT IS VERY WELL-CONFIRMED.

 

[Andyw2100]

Nice try, not going to spend my time with detailed response to pot shots.

Consider it a pot shot if you want to, but it is also accurate.