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Drafting (7) behind a U-Haul made ~60 wh/mi difference

Discussion in 'Model X: Driving Dynamics' started by scottf200, Aug 30, 2016.

  1. scottf200

    scottf200 Active Member

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    Long weekend helping a friend. Drove him from Chicago suburb to Erie PA on Sat using auto-pilot and traveling mostly 70 MPH (see red). On Monday, I followed him as he traveled in the small U-Haul without cruise control and driving mostly 65 MPH. I was following him using auto-pilot on the 7 setting (see yellow). MAJOR difference even at 7 and much more than the 5 MPH difference.

    335.93 wh/mi average on way there
    276.28 wh/mi average on way back
    _59.65 wh/mi difference

    [​IMG]

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    • Informative x 4
  2. GordonBremer

    GordonBremer Member

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    • Like x 1
  3. shokunin

    shokunin P85 & S40

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    Well there's also headwind that needs to be considered. Wind direction typically provides a bit of tailwind if you're heading east and headwind on your return going west.
     
  4. scottf200

    scottf200 Active Member

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  5. cmc5dc

    cmc5dc Member

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    Could it have been you were going at a.slight incine to and returning at a slight decline? Would be nice to confirm any elevation on that particular route by using the website.
     
  6. Xenoilphobe

    Xenoilphobe Active Member

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    You also had a 5 MPH reduction in speed, which helped
     
  7. ptsagcy

    ptsagcy Member

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    I wouldn't accept the difference as due to drafting. A setting of 7 is too far behind to realize much, if any, drafting advantage. More likely the speed difference or other conditions such as elevation change, temperature and wind. I just completed a round trip from NJ to Alexandria, VA - both ways going 75mph most of the way, with AP, and saw a difference of almost 40 wh/mi - much better southbound. Temps were 10 degrees higher northbound but otherwise everything was pretty much the same. According to EVTripPlanner elevation drops 249' southbound and gains 249' northbound. So, it would appear that the difference was due to the greater temp and elevation change. Draw your own conclusions.
     
  8. scottf200

    scottf200 Active Member

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    I have 15K miles on my 6 month old X and several roadtrips. I've *never* seen wh/mile as low as when I followed the U-Haul. Also did you see @GordonBremer testing he pointed to in the above thread link above? See underlined.

     

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