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Difference between Energy Usage Chart and Trip Odometer

Discussion in 'Model S: User Interface' started by rpavlicek, Mar 13, 2013.

  1. rpavlicek

    rpavlicek ***** Neophyte

    Joined:
    Feb 7, 2013
    Messages:
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    Location:
    Santa Clara, CA
    I noticed this more than once:

    I have the trip odometer reading in my dash -- it shows miles driven and wH/mile since last charge. I set the Energy Usage Charge to last 30 miles (average).

    When I reach 30 miles on the trip odometer ("since last charge") I expect the average wh/Mile to be the same on both...but they aren't.

    Can anyone explain why they are different?
     
  2. Todd Burch

    Todd Burch Electron Pilot

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    Smithfield, VA
    Others have noticed this too. Nobody knows for sure why at this point, though.
     
  3. gtimbers

    gtimbers Member

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    Location:
    Van Nuys, Ca.
    I have done that twice and both times the results were very close. Within 1 Wh/mi. Both times I was driving rather consistently with nothing demanding occurring.

    The odometer gauge has the exact energy usage and miles travelled so the math is simple. The energy usage graph probably uses averaging techniques rather than taking each exact point within the 30 minute window. This means that for uniform energy usage, the results will be similar, however, for more peaky usage, the results may start to vary. In my profession, we run into these inconsistencies all of the time. I deal with acoustic signals and dealing with noise signals (which would be like the energy graph) is a bear. Averaging time, windows and bandwidth can yield very different results for the same input signal. This is only a guess on my part, but the similarities are there. Agreement to a percent or two will probably be the best we can expect.
     
  4. SuperCoug

    SuperCoug Model S Res #7734

    Joined:
    Mar 16, 2012
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    Location:
    Bothell, WA
    I think you are right. Today I noticed that after I had climbed a long hill it showed an significant period of very high (off the range of the chart) usage of over 900 but if I changed the view to 15 miles then that same peek was only around 700 and if I changed the view to 30 miles it fell further to less than 600. Therefore, it is clearly doing quite a bit of averaging and in turn doing math on the averaged (not actual) values.
     
  5. toto_48313

    toto_48313 CAN P #5

    Joined:
    Dec 14, 2012
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    Montreal suburbs
    #5 toto_48313, Apr 2, 2013
    Last edited: Apr 2, 2013
    This morning I put my tripmeter at 0 just before I unplugged my car.

    Then I drove and I can see a difference between the "since last charge" and the Trip B, even if the distance is the same there is a 0.1 kWh difference between the total energy

    [​IMG]



    At the end of my ride, the 0.1kWh difference was still here.

    [​IMG]

    And the display on the last 25 km ( which is almost the distance I did) the average value is exactly in the middle of the average energy value.

    [​IMG]
     

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