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Modeling cargo box in EV Trip Planner

Discussion in 'Model S' started by Wuggado?, Jan 17, 2017.

  1. Wuggado?

    Wuggado? Member

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    Apr 24, 2016
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    Location:
    East Bay Area, CA
    Has anyone ever attempted to model a cargo box in EV Trip Planner? It seems to me best approach would be to add additional wind to the equation. The question would be how much wind to add. I just picked up a Thule Motion XT XL Limited (new to the market) which is supposed to be more aerodynamic than all their older boxes.

    I was thinking of going with +15 mph, but would love to hear thoughts on whether that is too much or not enough.

    Thanks!
     
  2. MorrisonHiker

    MorrisonHiker S 90D 2017.28 c528869

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    On ABetterRoutePlanner.com, you can indicate the Wh/mile. If you do a test ride at 65 mph, you could see the consumption and then plug that number in on the site.
     
  3. Marcboy

    Marcboy Member

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    Seattle, WA
    My non scientific test showed me this summer that a Yakima skybox 16 was adding 15% more consumption on the battery. I have a 60, so it was adding some anxiety. Highway speed, no speeding.
     
  4. kort677

    kort677 Active Member

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    florida.
    with no headwinds depending on the profile of your box you should probably deduct 15-25% of your range if driving at the legal highway speeds, reduce your usable range more if climatic conditions are unfavorable.
     
  5. Wuggado?

    Wuggado? Member

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    Thanks for the idea. I have yet to take a multi-charge trip, so I don't have practical experience with either planner, but the concern I have with ABetterRoutePlanner is it doesn't seem to take into account variables that would affect range such as wind, payload, cabin temp, and outside temp. I definitely don't have enough experience with the car to take all those variables into account myself and predict the Wh/mile.
     
  6. Wuggado?

    Wuggado? Member

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    Location:
    East Bay Area, CA
    Thanks for all the previous ideas. Wanting to have some way to model a cargo box nicely within EV Trip Planner (so the multiple stops are all accounted for with each other stop in mind), here's how I decided to go about it:
    • Do a range test, with and without the cargo box, on a 40 mile round trip, one right after the other so the conditions were as close to the same as possible.
      • Speed +9 freeway/+5 city
      • Outside temp - 64 degrees F
      • Cabin temp - off
      • Wind - calm
    • Result was 21% more kWh used with the cargo box
    • Played with headwind in EV Trip Planner until kWh used was 21% more. This was done for several distinct segments of a multi-day journey and using an 18MPH headwind pretty consistently showed around a 21% range hit.
    I will use this on the actual journey in a couple of weeks and try to remember to report back how it went.

    BTW, yes I realize that varying different aspects of the journey (such as actual wind speed, outside temp, speed, etc) could yield a different range hit, but I just didn't have the time or patience (or control of some of the variables), to gather data points for all possibilities. I will probably bump the wind speed up to 20MPH just to give a margin for error.
     

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