Tesla Admits To Sometimes Limiting Battery Output / HP If Launch Mode Is Used Too Often

2 months ago by Eric Loveday 21

Launch Mode Details Via Tesla

Launch Mode Details Via Tesla

It seems as though Tesla keeps a relatively close eye on Launch Mode usage in certain versions of the Model S (P90D) and probably on other non P100DL versions of the S and X too (see Tesla’s statement below).

Tesla Model S P100D Ludicrous & Tesla Model S P90D Ludicrous

Tesla Model S P100D Ludicrous & Tesla Model S P90D Ludicrous (via Tesla Racing Channel)

Launch Mode is only available on dual-motor Teslas and it’s there to extract the maximum in off-the-line acceleration, but it appears as though over time, Launch Mode can lose its oomph, so to say.

One Tesla Model S P90D owner experienced this apparent loss in Launch Mode power, so he reached out to Tesla and then posted this on Tesla Motors Club Forum (via Electrek):

“Unfortunately I’m here to say this is true. My car was limited just after the 8.0 update and at first I was convinced it was related to that. I did lots of testing and emailed Tesla my findings. Before this limitation my car would pull around 1600 amps from the battery and 512 KW of power when fully charged, now the car will only pull around 1500 amps and 480 KW of power, a loss of about 40 HP on a 4 month old car.”

A Tesla representative responded to his inquiry with this statement:

“Thank you for your time. To recap our conversation, using launch mode places an increased stress on the entire powertrain accelerating aging and fatigue of various components. The computer systems automatically track launch mode usage and continually estimate fatigue damage. Depending on how launch mode is used, the computer may eventually limit the available power during launch mode to protect the powertrain. Note that this is a common strategy also employed in other high performance cars. As discussed, upgrading to the P100D ludicrous will remove this limit and will not be limited in the future as the P100D does not have this limit for launch mode.”

Launch Mode shouldn’t be overused. It’s there for that occasional situation that warrants its usage. On-track racing typically voids warranty. It seems Tesla is attempting to protect the vehicle, rather than allowing over usage that could lead to component failure.

Electrek asked Tesla for comment on this and received this response:

“Like other automakers, our performance vehicles continually monitor the condition of various components and may employ limiting strategies to reduce fatigue on the powertrain.”

Seems acceptable to us.  The only issue of course is that Tesla has not communicated this limiting of output could be implemented at the point of sale, which opens the company up to further scrutiny, or perhaps another round of legal action on performance, as found earlier with how Tesla was reporting the motor output on some of its vehicles as compared to actual real world performance.

Source: Tesla Motors Club Forum via Electrek

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25 responses to "Tesla Admits To Sometimes Limiting Battery Output / HP If Launch Mode Is Used Too Often"

  1. Pushmi-Pullyu says:

    Whether Tesla should, or should not, limit Launch capability this way, is a matter for debate. Obviously there are good arguments to be made on both sides.

    What should not be a matter for debate is that Tesla absolutely should not have taken the step of limiting power available from Launch mode without informing its customers. Not doing so makes it look like Tesla was deliberately hiding something.

    And this isn’t the first time Tesla has done such a thing. You’d think that learning would have taken place, but it hasn’t. Why would any company try to hide something that people are eventually gonna figure out? Best to state it openly, and eliminate the accusations that will only feed into the anti-Tesla bashers’ rhetoric.

    Just like politicians trying to hide nefarious activities by their underlings: What really gets people mad isn’t so much the initial offense, it’s the coverup.

  2. pjwood1 says:

    “Seems acceptable to us”

    Why would it be acceptable to have your car limited, through on-board computer monitoring or updates (who knows?), and then have the company that sold it to you try and say they won’t do it…if only you’d “upgrade to the ($150k) P100D lucicrous”?

    Tesla should name companies, or at least methods, where other OEMs are muting performance not because of wear, but in prevention of wear. “They do it, so can we” doesn’t make all warm, fuzzy and accepting.

    1. Nix says:

      I can name two right off the top of my head.

      BMW 335’s with twin turbos. They got a power cut:

      http://www.bimmerforums.com/forum/showthread.php?1574762-BMW-is-secretly-de-tuning-the-n54

      Closer to our EV home, the Honda Civic PHEV got a flash to reduce the amount of battery used, to avoid killing the battery prematurely. This reduced both performance and MPG.

      It would probably be easy to find more examples.

      Every time you go in and they flash your car, they can fiddle with the computer in order to make your car last longer and prevent problems.

      1. Zim says:

        Well frankly I don’t think we should accept this sort of bulls*** from either Tesla or BMW!

  3. georgeS says:

    The gear strain stress is excessive in those situations. The Motor is loaded to max and then we have lots of current and heat to deal with as well.

    The drive unit is physically not build for an unlimited number of cycles of this kind of loading.

    Therefore Tesla limits the amount of cycles you can put on the drive train to be in line with the design limit.

    It makes sense to me.

    1. Pushmi-Pullyu says:

      Frankly, it doesn’t make sense to me. If it puts that much strain on the drivetrain, then the car shouldn’t be engineered to do that at all. Not even once.

      Or, to argue from the other direction, this indicates the drivetrain needs to be beefed up… and the frequency of failure, the “milling noise” problem which was frequently reported early on in Model S production and still pops up sometimes, seems to be another indication that Tesla needs to beef up the drivetrain, or at least certain parts of it such as the (reduction gear) gearbox.

      1. georgeS says:

        “If it puts that much strain on the drivetrain, then the car shouldn’t be engineered to do that at all. Not even once.”

        No offense but I can tell you have zero engineering background.

        The drive system is designed for a certain number of cycles. It is not un like a battery that also has a “cycle life” as the engineering term goes.

        So your statement makes no sense.

        1. SparkEV says:

          Technically, you are correct. However, a well engineered product should last the lifetime of its expected usage (ie, warranty period). If that means exercising to the fullest extent of its capability, then it should be so. That’s how we run things with electrical engineering devices; if it breaks on peak usage, that’s deemed poorly engineered product.

          But when it comes to cars, they are often designed to break at full usage (ie, clutch slip too often). It’s not that cars are poorly engineered, but EE do far better. 😉

          1. pjwood1 says:

            ..especially if the at is marketed as “insane, or “ludicrous”. It should be engineered for long term performance. We don’t know the counter, and I am cynical it only trips after, say, a hundred launches. We don’t how many. We know if we upgrade we (supposedly) escape what may be a slippery slope of forced obsolescence.

        2. Pushmi-Pullyu says:

          georgeS

          “No offense but I can tell you have zero engineering background.”

          Wow, what a belittling and grossly oversimplified statement. Double points for saying “no offense” when you clearly meant to be insulting.

          Dude, I can read. For example, I have read that when designing a bridge, engineers use a rule of thumb: the bridge is designed to hold 200% of the weight it’s rated for, as a margin of safety.

          On the other hand, I think most of us who can read know that gasmobile race cars are built so that the driver can “redline” the engine; to push it past its maximum safe RPM speed for short periods of time, altho of course there is always the risk of “blowing” the engine if it’s redlined, especially if it’s redlined for more than a very brief time.

          So the question here — contrary to your your ignorant and insulting remark — is just what approach Tesla should use in designing and building a Model S or a Model X.

          Since both the MS and MX are mass produced cars aimed at general car buyers, and are not actual race cars, then I submit that they should be built so that you can’t push the drivetrain past a safe operating limit.

          And I don’t need to be an engineer with years or decades of experience to understand that. It’s just common sense, something which unfortunately seems to be in short supply these days.

    2. Chris says:

      Even Nissan limited the torque on the Leaf, although that wasn’t hidden, it was at a model year change.

      1. Pat McSwain says:

        Nissan and most other do limit launch torque from the factory at 0 miles.

        Tesla’s system is unique. It allows you to feel what the car is capable of, then cuts the power.

        This a bad precedent for all high performance car makers. Sure, void our driveline warranty. Sure gimp the car at launch.

        Don’t sell a car that hauls ass the first day, then make it go slow after you’ve made sure the check cleared.

  4. jelloslug says:

    Tesla should have informed customer about the limitations up front.

  5. Pat McSwain says:

    Bull.

    Some mfr’s will void driveline damage when dragracing. Others will limit torque from the factory.

    I would LOVE to see an example of a car that detunes itself due to high performance use.

  6. Pat McSwain says:

    By the way…

    The World’s Most Evil Automaker will not void your driveline warranty for beating the s**** out of the car on the track, as long as you have not modified it.

    Been there, done that. It’s not just a claim, it’s not a rumor, they really fix the car for free for pushing the car to 100% on a closed course. Unlimited except by normal warranty duration.

  7. Jason says:

    They don’t specify the actual reason why they are limiting the launch performance. It sounds like many reasons, if the battery degradation is increased, then there is also natural reduction in performance as the batteries will not produce the same amount of power as new.

    I don’t know why people would be surprised about some of these Tesla issues. In an ICE car if you red line it every single time, then you know at some stage you will blow the gear box. We all applaud how Tesla can/do over the air updates and manage the car. Mostly that has been good improvements, now we are seeing an instance where they are protecting their car. Still sounds like a good thing to me. 1600 vs 1500, 512 vs 480, how many ice lose power over time or with prolonged high performance? Don’t think my last car explicitly stated I would lose power over time, and seems like there are many examples of the same story of thing in these comments.

    Tesla is not God, they are pretty good, but still just a company selling a product in the most positive light they can. 70k sales and one person has measured and reported this loss, sounds like the majority are plenty happy to me.

    1. Pushmi-Pullyu says:

      Jason said:

      “…if the battery degradation is increased, then there is also natural reduction in performance as the batteries will not produce the same amount of power as new.”

      We’re not objecting to any natural reduction in power from the battery pack, or any natural reduction due to anything.

      What we are objecting to is an artificial limitation which is, apparently, suddenly engaged if the car detects you’ve “pushed the pedal to the metal” more than X number of times; and we’re objecting that Tesla has decided to do this without announcing it to new car buyers.

      On the one hand, Tesla keeps bragging about how their cars keep pushing the 0-60 performance higher and higher. But then they turn around and limit the ability of their cars to do that more than X number of times.

      It may be an exaggeration to call this deceptive or dishonest on the part of Tesla, but at the very least they haven’t been open about it. Even if you can find cases of other auto makers similarly limiting — after a “break-in” period — the performance of their high-performance cars, that doesn’t make it an acceptable practice.

      If it was a universal practice, that would be a valid defense. But it’s not, and in fact I strongly suspect it’s very rare. In any case, it’s not acceptable at all.

  8. ModernMarvelFan says:

    All EVs do that to limit damage to powertrain and battery.

    Volt, LEAF, Prius Prime, BMW i3, Ford Energi series all do that as well.

  9. Loboc says:

    “This is for your protection during the transition period.” – VIKI-controlled robot army.

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