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P85D Range/Delivery Impacts on TSLA

Discussion in 'TSLA Investor Discussions' started by 3mp_kwh, Dec 23, 2014.

  1. 3mp_kwh

    3mp_kwh Member

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    Is that what they know? All November, buyers were told 275 miles, at 65mph. Rob says EPA is "bogus nonsense". What if people like Rob can't get close to 275, at 65mph? Despite your rational understanding of mechanical efficiency, it isn't the rationale some of these buyers probably used. Maybe the acceleration will make all better.
     
  2. SteveG3

    SteveG3 Active Member

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    as to range confusion with P85D, at least a partial, "bazinga" from Elon:




    [​IMG]Elon Musk @elonmusk · 11m11 minutes ago

    Software update to achieve max efficiency (going to full idle on 2nd motor) is not out yet. Range of P85D should then closely match P85+.

    https://twitter.com/elonmusk/with_replies











     
  3. FluxCap

    FluxCap Active Member

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    [​IMG]
     
  4. chickensevil

    chickensevil Active Member

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    I'm sorry but this causes more questions than it answers. Is the "range" EPA range or just their ideal? Because I thought the p85d was already supposed to have higher range than the p85? So the if this is an adjustment to EPA then that is an even bigger boost to the range right?
     
  5. SteveG3

    SteveG3 Active Member

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    OT

    When I first started reading and watching interviews of Elon I found myself thinking- cross between Sheldon and Ari Gold from Entourage (though I've only ever seen maybe a couple of hours Entourage). Certain remarks from Elon to this day have me and my brother asking each other... did you hear what "Sheldon" said today (i.e. Analyst (sounding afraid he's suggesting something absurd): "so you think within ten years you can get battery costs under $100 kWh?", Elon: "Seems pretty obvious to me.").

    I kid... of course, Elon is Elon, and it's awesome to have him here.

    - - - Updated - - -


    Yes Chicken, it's merely a partial Bazinga... not a full one. I suspect the software update he is referring to will get the car up to the new EPA numbers. I also suspect that those new EPA numbers are based on something less than a 100% charge, but I couldn't tell you exactly what percent. Hopefully, soon enough, they'll explain why EPA came in at 250 miles despite same overall efficiency (89 MPGe IIRC) as original testing. I think what's most helpful is there's something we can make some sense of... max efficiency of P85D about same as P85+.
     
  6. Gerasimental

    Gerasimental Member

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    I'm not even sure it's really a 'boost' to range. Seems more like 'They've been running at below nominal range until now because they didnt have the software yet. That will soon change and you'll have the advertised range (be it EPA or their own estimate)'. He doesn't say anything like 'new P85D will maximise efficiency and increase range to same level as P85+'.
     
  7. anticitizen13.7

    anticitizen13.7 Enemy of the Status Quo

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    That was my impression too from the event in October, but Tesla's website is now showing 250 miles EPA range for the P85D (with slight loss when equipped with 21" alloys), and 265 miles EPA range for the S85D. While same or only slight loss from AWD is still better than what we get from gasoline engines, it's not as impressive as the company's initial claims.

    On the plus side, the reports from P85D owners indicate that overall quality is very high on the new units (specifically that the cars feel better put together and also handle with noticeably increased confidence).
     
  8. jhm

    jhm Active Member

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    I wonder if when they labeled the normal/sport/insane modes, they should have gone with "max range" instead of "normal". I know the EPA is bent on testing in least range mode, but Tesla should be able to make clear statements about how max range mode is able to extend the range beyond insane mode. Clearly, for the driver, when your travel plan puts a premium on range, you'll value max range mode. It seems that the EPA should be encouraging all car makers to develop driver assist features that enhance fuel efficient driving and should not penalize or overlook this in energy efficiency ratings. Autopilot opens up whole new vistas for making driving more energy efficient. So I would expect that Tesla will continue this line of development.
     
  9. RyanT

    RyanT Member

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    #9 RyanT, Dec 23, 2014
    Last edited: Dec 23, 2014
    The software that switches from 2 motor 4 wheel drive to 1 motor 2 wheel drive mode wasn't finished at launch evidently. P85D's have been running in 4 wheel drive mode all the time.

    I think they did the right thing in the situation. They felt pressure to release the car on time. The software wan't ready for the normal mode where it idles one motor. In the tweet i think he's saying when they get the switch to normal mode it's going to have a 265ish mile range displayed. Hopefully the epa numbers get updated with normal mode, if not I'm sure they'll highlight the normal mode range on the product page.

    It makes sense that they drove the cars with one motor powered down and knew it was more efficient before the D event and that's why they highlighted it. The only other thing I can think of would be to release it with normal mode only powering one motor but then they would just have to change it when they got their official "normal" mode software finalized.
     
  10. Raffy.Roma

    Raffy.Roma Active Member

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    The P85D has such an high technical level to allow margin of improvements that we cannot even image. IMO we will see other improvments like this in the future.
     
  11. Papafox

    Papafox Active Member

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    #11 Papafox, Dec 23, 2014
    Last edited: Dec 23, 2014
    Remember that the P85D has bigger motors and different inverters than the S85D. Thus, the original claim of better mileage with the "D" series can still hold true, even if the P85D turns out to be about even with the P85+. The P85D will offer a substantial increase in horsepower plus the benefit of all wheel drive with virtually no increase in energy consumption once a little tweaking is done. Of course the driver will have to change driving modes to maximize range versus maximize handling and acceleration. As Tesla achieves this goal they will have done something incredibly noteworthy.

    Looking forward to seeing the numbers for the S85D. I expect we will indeed see better mileage than with the S85. Tesla already has the basic formula for the tweak worked out, otherwise they would not have made the better mileage claims. The EPA numbers are at the mercy of the EPA methodology, but I believe that former S85 drivers will indeed notice a mileage improvement with the S85D.

    Some of us have highly predictable driving patterns. My commute to work in a 40/60kwh Model S is mostly highway and I get between 279wh/mile and 282wh/mile when my drives are averaged over a week or two. Lots of other drivers commute with highly-predictable patterns, too. Even if the EPA numbers change, real-world experience will give us the answers we need, which is one of the benefits of belonging to Tesla Motors Club, where we compare notes.
     
  12. SteveG3

    SteveG3 Active Member

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    Yes... the tweet relates to efficiency improvements, but if anyone missed this in coming months there will be performance improvements (from the bottom of the order page on Tesla's website):

    "The P85D top speed is currently electronically-limited to 130 mph. In the coming months, we will be able to upgrade the car free of charge to enable a 155 mph top speed. This free update will be available for the lifetime of the car (not limited to the first owner). Additionally, an over-the-air firmware upgrade to the power electronics will improve P85D performance at high speed above what anyone outside Tesla has experienced to date. In other words, the car will be better than you experienced. This free upgrade will be rolled out in the next few months, once full validation is complete."

    ps... from new video early this morning, performance already looks pretty good (apparently this Lamborghini starts at $400K. "thrust mode" not engaged on Lamborghini),

    Tesla Model S P85D vs Lamborghini Aventador Race - YouTube
     
  13. mulder1231

    mulder1231 Active Member

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    The way I heard Elon's explanation at the D event (I was there) of greater range for the dual versus single motor cars was that the D can have greater efficiency because dual motors provide better distribution of power to the four wheels. If one motor is turned off, how can that be more efficient? You still have the extra weight of the front motor. Hope Elon will follow his tweet with another blog on this topic soon.
     
  14. mejojo

    mejojo Member

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    One possibility:

    Imagine that getting from 0 - X mph is more efficient using 2 motors, and in fact using 2 motors is required for AWD acceleration and handling.

    But imagine also that cruising along in a straight line in good conditions (hopefully a large percentage of miles) using 1 motor is more efficient than running 2 motors.
     
  15. chickensevil

    chickensevil Active Member

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    At higher speeds because the front motor is geared differently if you reduced power to the rear motor and increased power to the front motor you would have a more efficient system. It is a way to cheat shifting gears without actually shifting anything.
     
  16. vgrinshpun

    vgrinshpun Active Member

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    Somebody posting right after the event, based on their conversation with a drivetrain engineer, mentioned that gearing of two mottors is almost identical.

    During the test drive with Betty Liu on the day of the event Elon said that gain in efficiency is due to the fact that a motor efficiency curve has a maximum at certain speed, and these maximum efficiency points for rear and front motor are at different speeds. So apportioning power (either 100% or just more than 50%) to a motor that is running at higher efficiency at a given speed allows for efficiency-speed optimization.
     
  17. chickensevil

    chickensevil Active Member

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    Oh, thanks for that, motor sizing difference instead of gearing. Still if they can fully cut power to one motor and let the other one take full control over the car it is likely to be the most efficient if you are just maintaining a certain speed on flat terrain. So having that option for "normal" mode is likely to be a nice benefit. I assume instead that the 85D will have two different gears since it is supposed to have the same tiny motor for both front and back. And will likely come with a "normal" and "sport" mode. Based solely on their comments about it having higher range and more efficiency over the 85.
     
  18. jhm

    jhm Active Member

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    This makes sense. Differences in the two motors lead to two different sweet spots. So cruising at a particular speed you want the bulk of power to go to the motor nearest its sweet spot. You only need the other for traction, substantial acceleration and regenerative braking. What continues to puzzle me is why the code was not written to optimize this in the first place. Did they know the were coding a suboptimal algorithm in the first round, or have they discovered something that they now see how to exploit for greater efficiency? Was it expediency or have they learned something new?
     
  19. Raffy.Roma

    Raffy.Roma Active Member

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    in electronics it's always like this. First you make a design and think you made the best design. But then you realize that your design can be improved.... and improved.....and improved.
     
  20. chickensevil

    chickensevil Active Member

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    For the P85D it would be at least three different code sets. Normal, Sport, Insane. They probably coded insane first for the purposes of pushing the car to the limits... it was probably also the "easiest" since you just tell the car to always have full power available to both motors at all times. Then they likely started work on the second mode which became "sport" as a means to do a smarter algorithm that would not require full power all the time but would still have very great AWD handling. If I were to guess, the "Normal" mode came after this in the sense that they wanted to see what they could do to maximize efficiency on the car. This is likely the most complex to code because you have to take all the conditions of the car into account (traction, power to maintain a given speed during for a given plane, power to increase (or decrease in the case of regen) acceleration for a given plane, etc) there are likely many variables that have to go into that equation and it changes for every change in MPH. Clearly they knew this was a goal during the reveal event since it was a point of conversation by Elon. It was just not ready for prime time since it was a more complex algorithm to program and get right.

    Anyway, that is my WAG on the process and order flow of events... and why we are only just now getting word about "normal" mode finally coming to the cars.

    - - - Updated - - -

    And also, this! Haha! It depends on what your goal was, Power, traction, or efficiency... each have their own coding challenges.
     

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