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My trip meter is showing more miles than my odometer

Discussion in 'Model S: User Interface' started by Jeff Andrews, Feb 13, 2014.

  1. Jeff Andrews

    Jeff Andrews Member

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    Not sure how or when this started happening, but I just noticed it today. The odometer catches up after about 1/4 mile.

    pmE76rNl.jpg

    (Trip B is reset for winter weather to see how much more energy I use.)
     

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  2. pilotSteve

    pilotSteve Member

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    Uhhhhh rounding error! Come on :wink:
     
  3. brianman

    brianman Burrito Founder

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    Here's another one to ponder:

    TotalEnergyTripMeterInconsistency.jpg

    "But but... maybe your car started with some weirdness with Trip B starting after some climate control or something"

    Ok, but that doesn't explain how the gap rose from 0, to 0.3, to 0.6, to 0.7, and now 0.8 over the last year+.
     
  4. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

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    8900.6/8899.8 = 1.00008988966044180768
    8899.8/8900.6 = 0.99991011841898298991

    Four zeros after the decimal point is somewhat smaller than I can see. Precision != accuracy. I'd put it down binary math rounding errors. In automotive measurements, outside of a testing facility, there are so many variables that I use +-5% as whether things are significant or not.
     
  5. brianman

    brianman Burrito Founder

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    #5 brianman, Feb 15, 2014
    Last edited: Feb 15, 2014
    You're assuming it's stored as a float (especially a < 32 bit float) which would have been a horrible choice on Tesla's part, IMO.

    Here's some of what I see in my pictures...

    0









    11096.8 4332.5 390
    11096.8 4332.5 390
    0.1









    11324 4414.1 390
    11324 4414.2 390
    0.2









    12233 4729.5 387
    12233 4729.7 387
    0.3









    13482 5180.1 384
    13482 5180.4 384









    15061 5808.7 386
    15061 5809.0 386
    0.4









    15162 5841.7 385
    15162 5842.1 385









    17029 6522.5 383
    17029 6522.9 385
    0.5









    18508 7071.5 382
    18508 7072.0 382
    0.6









    19376 7512.2 388
    19376 7512.8 388
    0.7









    20731 8057.5 389
    20731 8058.2 389









    21776 8454.4 388
    21776 8455.1 388
    0.8









    21884 8504.2 389
    21884 8505 389









    22892 8899.8 389
    22892 8900.6 389
    0.9









    23357 9115.6 390
    23357 9116.5 390
    Just looking at these numbers, it appears the separation is growing more quickly with mileage. This is the opposite of how I would expect float rounding issues to surface.
     
  6. jcaspar

    jcaspar Member

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    I would just reset Trip A. Problem solved!!:wink:
     
  7. davewill

    davewill Member

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    A man with two clocks never knows what time it really is.
     
  8. aviators99

    aviators99 Model S - R140

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    Maybe Ferris Bueller was right?
     
  9. neroden

    neroden Happy Model S Owner

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    See what it looks like in kilometers? This has all the hallmarks of two different rounding algorithms being used during unit conversion.
     
  10. medved

    medved Member

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    Can someone tell me please how to put the trip meter where the OP has it; but i would prefer it on the right side. Thanks
     
  11. Chipper

    Chipper Active Member

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    Just hold down the scroll wheel and select what you want and where you want it. Works for both sides.
     
  12. moviemaker2000

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    I have noticed that if you try rebooting the dash while the car is in motion the odometer will read 0 miles for a few seconds while it cycles through the initialization process. I haven't noticed the same behavior on the center screen (trip A/B). So, if you have ever rebooted while moving it probably isn't recording the fractional miles you travel during those few seconds it is reading 0.
     
  13. medved

    medved Member

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    when i do that on the right side there are options to choose from but not the trip meter. And when i do that on the left side it just pauses the music.
     
  14. tslas

    tslas Member

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    You need to keep it pressed down approx 3 seconds
     

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