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Why do PxxD have lower range than xxD?

Discussion in 'Model S' started by jankratochvil, Jun 11, 2017.

  1. jankratochvil

    jankratochvil Member

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    PxxD have about 3..8% lower range in EPA/NEDC range tests. But those tests have no extreme acceleration parts nor slippy roads so Tesla should keep using the more power efficient front motor. And the front motor is the same on both PxxD and xxD so why is there any range difference at all?
    P100D/100D EPA 315mi/335mi=-6% NEDC 613km/632km=-3%
    P90D/90D EPA 270mi/294mi=-8.1% NEDC 509km/528km=-3.6%
    50kg weight difference of the rear motor should not have such a big range impact.
     
  2. d.c.palmer

    d.c.palmer Six years of EV driving

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    There are several parts to the answer:-

    1. Performance cars may well have different tyres (e.g., the stickier Michelin Pilot Super Sport is currently fitted to staggered 21" wheels, c.f., the Continental tyres fitted to lesser models). Stickier performance tyres are less efficient (but more fun).

    2. Economy varies depending on whether or not "Range Mode" is enabled (see below).

    3. Performance cars are rear biased: the beefier (and "thirstier") rear motor is used much of the time; the smaller front motor - as I understand it - is only used when required for traction.

    When the system allows it, non-Performance cars can act as front-wheel drive cars - or rear-wheel drive cars - depending on what the system feels is most appropriate for the driving conditions. That allows for reduced losses - more efficiency - at the expense of driving pleasure (rear-wheel drive is just nicer - at least, for those of us purists).

    Performance cars are different. They are designed for those of us purists who prefer a rear-biased system: this gives better acceleration and nicer steering (less corruption from the front motor). They do allow use of both motors when needed, and when in Range Mode the system can "torque sleep" one or other motor.

    (TEST: try turning range mode on and off as you drive along a winding road and accelerate through the corners; you'll hear a LOT more whine from the front when Range Mode is on - demonstrating that the system is putting greater emphasis on the front motor.)

    I'm not sure whether the Performance cars ever become fully front-wheel drive, however - other forum members may have greater insights here. My experience is that the car is much less fun to drive in Range Mode (too much front emphasis for my liking), but I don't think it's ever fully front-wheel drive.
     
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  3. chillaban

    chillaban Active Member

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    Parts of the performance cycles require using full throttle or other percentages of max throttle. Full throttle until 45mph, full throttle for 5 seconds, etc etc etc. Of course in a performance car, that will result in better performance and higher power output levels than requested from a non-performance car.

    It's worth mentioning although the front motor is hardware-identical between the P and non-P models, per the manual, the P front motors are software tuned for a higher peak torque output.

    And the non-P cars gain a few percent efficiency from balancing the power output between both the front and the rear motors, except the P models can't do that as well because their rear motor is inherently larger and less efficient.

    Finally, remember that fuel economy tests MUST be done in the default mode of any car. Manufacturers are not allowed to put cars into range mode (though they are allowed to attempt to detect the test cycle conditions and attempt to game the test by switching into a more efficient mode automatically). This means that unless you want your P car to always drive like a slug when you drive it, the differences are going to show up on an EPA testing cycle.


    And FWIW, in my experience, the P cars are where the Range Mode switch truly makes a noticeable difference. The switch in my two non-perf dual motor cars is basically a placebo button. But in my Performance loaners, I've seen cases where even in highway driving I can get 100% correlated 5% drops and increases in Wh/mi ratings just by flipping the Range Mode switch.
     
    • Informative x 2
  4. jankratochvil

    jankratochvil Member

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    Is there known the differences of PxxD vs. xxD range in range mode? Yes, I have already tried to Google it.
     
  5. TIppy

    TIppy Member

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    #5 TIppy, Jun 11, 2017
    Last edited: Jun 11, 2017
    This is from Tesla's theory of operation manual:

    Driving Modes
    Model S provides the following selectable driving modes:
    o Standard
    o Range
    The difference between the two modes is the amount of energy consumed by the thermal management
    system.
    In Standard, the thermal management system is fully operational to keep the occupants at the desired
    humidity and temperature, while maintaining the battery temperature within its nominal operating range.
    Range mode reduces vehicle power consumption by modifying the thermal management strategies:
    o It allows the HV battery to operate within a wider nominal temperature range, which reduces the
    energy consumed for cooling and heating of the battery.
    o It restricts cabin heating and cooling capacity, which reduces energy used by the AC compressor,
    PTC heater, and blower motor.
    Powertrain performance and behavior are not affected. Once Range mode is selected, it remains engaged
    until Standard mode is re-selected.

    NOTE: This mode is only applicable to driving, and is distinct from the charging system s Range mode.
    Driving Range mode and charging Range mode can be used together or individually, depending on the
    driver s requirements.


    So you guy's are psyching yourselves out about differences in driving performance in range mode.

    The guy that holds the current range record for model s was told by Tesla that both a P and non-P model would get the same range if they were driven identically.

    My Model S P90DL uses only the front motor to cruise at 70 mph.
     
  6. chillaban

    chillaban Active Member

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    I don’t think that is entirely true. That documentation does not seem updated to reflect dual motors and torque sleep. You can audibly hear a switching noise different as you toggle the range mode on dual motor cars.
     
  7. TIppy

    TIppy Member

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    #7 TIppy, Jun 11, 2017
    Last edited: Jun 11, 2017
    Just copied this from my P90DL operating manual on mytesla:

    OPERATING MODEL S | 10
    RANGE & EFFICIENCY
    You can maximize your driving range with the same driving habits that you use to conserve fuel
    in a gasoline-powered vehicle. Energy consumption also depends on environmental conditions,
    such as cold weather and hilly roads. To extract the maximum mileage from a charge:

    Avoid frequent and rapid acceleration.

    Use regenerative braking to slow down by taking your foot off the accelerator instead of using
    the brake.

    Limit the use of resources such as heating and air conditioning. Using seat heaters to keep
    warm is more efficient than cabin heating.

    Pre-condition your Model S while it is plugged in. When plugged in with the climate control
    system activated, you can use the mobile app to remotely cool or heat the cabin. The vehicle
    will pull power from the wall, ensuring that you have optimal range when you’re ready to drive.

    Use Range Mode to automatically limit the amount of power used for the climate control
    system:
    CONTROLS > DRIVING > RANGE MODE > ON.

    Psych.
     
  8. chillaban

    chillaban Active Member

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    You know, you don't have to be rude when incompletely quoting from a manual.

    Press the little (i) next to Range mode. It says, amongst other things:

    In the owner's manual, additionally:
    So there is more to Range Mode than the theory of operation manual's segment. As with many other parts of Tesla's documentation, various pieces have been sporadically and inconsistently updated and not necessarily reflective of the current behavior.
     
  9. TIppy

    TIppy Member

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    #9 TIppy, Jun 11, 2017
    Last edited: Jun 11, 2017
    I don't see that language in my manual.

    Yeah, I said that my car uses just the front motor to cruise at highway speeds, but it does that whether I'm in range mode or not.

    I'll hook up my canbus analyzer and toggle the range mode to see if there is some noticeable difference in torque distribution. Is there some particular scenario you would like me to test?
     
  10. MXWing

    MXWing Active Member

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    Lead foot drivers tend to gravitate to P models.

    Sustained and faster acceleration at high speeds will reduce the range say versus a gradual increase to 65 and cruising in the middle lane.

    No complicated explanation needed. Any minutiae in tires, performance parts, bla bla is a small magnitude to lead foot factor. ;)
     
  11. chillaban

    chillaban Active Member

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    Interesting.... I read somewhere else that Tesla at least revised the "torque sleep" feature to apply whether or not you're in Range Mode, so maybe there's been other changes here.

    If you have an analyzer, I'd be curious to see both a cruising and a moderately accelerating workload. Where I sense the most "noise" difference in my 70D and 100D is when slowly accelerating (like increasing 1-2mph per second). With Range Mode Off, I barely hear the front motor's switching noise. But with Range Mode On, the front motor is much more pronounced.

    I'm 99% sure I'm not imagining it, but I don't have any numbers to back up my claims :)
     
  12. sorka

    sorka Active Member

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    I know Tesla claims that the P cars have lower wh / mile efficiency but in my experience that hasn't been reality. I've had two P85 loanders, three S85 loaners, and two S60s. Every single one of them has had slightly worse efficiency than my P85DL. Sure it could be the alignment and it probably is otherwise there's no way they'd be worse.

    Also, this is all on long multi hundred my freeway commutes. Stop and go with the larger mass of the larger motor and thicker drive shafts are likely to be less efficient but Tesla claims this is the case even during freeway cruising.

    Although the original interactive model they used to have had the P85D getting better range than the S60 at 60 MPH but it flipped again at 70 MPH.
     
  13. TIppy

    TIppy Member

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    Between what speeds are you slowly accelerating?.
     
  14. chillaban

    chillaban Active Member

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    0 to maybe 60?
     
  15. TIppy

    TIppy Member

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    Did they all have the same suspension lowering settings at highway speeds?
     
  16. EV-lutioin

    EV-lutioin Active Member

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    Has anyone determined what percent increased range you will get from being in range mode?
     
  17. whitex

    whitex Active Member

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    Just for reference, we have 2 MS - a P85D and 75D. When traveling together, I noted a the Wh/m a few times and they were always within 1% of each other. Now, since we drove together it was a steady ride without P85D trying to outaccelerate the 75D, but since usually one car was following the other, they experienced the same distance and road conditions. 75D's heater is set a little higher as my wife likes it warm. We never use Range Mode. P85D is always set to Ludicrous mode.

    The 75D actually has a higher rated mileage than P85D, but I'm not convinced it would go any farther.
     
  18. TIppy

    TIppy Member

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    @chillaban ,
    Set my P90DL to sport mode.

    Started at 30 mph and engaged cruise control to 60 mph. That caused the car to accelerate at about 3 mph / sec.
    In range mode the torque is biased toward the smaller front motor.
    In non-range mode the torque is biased toward the rear motor until about 55 mph then switches completely to the front motor.

    With the cruise control set at 50 mph and stable, the torque switches completely to the rear motor in non-range and then completely to the front motor in range mode.

    When I was doing acceleration tests from 70 to 90 mph and had the cruise set for 70 only the front motor was being used in non-range mode.

    So it seems they do some range optimization in both modes, but it's definitely different between the two modes.
     
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  19. chillaban

    chillaban Active Member

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    Thank you sir for doing this test! Really interesting the differences between the two modes.
     

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