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Modeling cargo box in EV Trip Planner

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

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  1. Wuggado?

    Wuggado? Member

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    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 2017.42

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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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    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 Banned

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    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.
     
    • Helpful x 1
  6. Wuggado?

    Wuggado? Member

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    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.
     
  7. mreinhorn

    mreinhorn New Member

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    How did your trips go with the Motion XL? I'm considering purchasing it vs the hyper XL. Looking for something for skis in winter and camping gear in summer. I have a 75D and have avg 276 Wh/mile for the last 4500 miles this summer. I installed the tesla roof rack yesterday and was hoping ot get to purchase a box tomorrow. Any feedback on range loss and any other advice is welcome.
     
  8. Wuggado?

    Wuggado? Member

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    Sorry, just saw your post. I liked the box a lot. I have not used a box before, but was told by the shop that it was one of the quietest you could get. The XL is a tad longer than I would have liked, but at the time the L was not available. It's just as well, though because the L would have been a bit tight for 4 sets of skis, boot bags, etc. If you have less than 4 sets to put in, and not a ton of camping gear, the L would not force you to have to slightly limit the opening range of the back hatch.

    As for range, using an 18MPH headwind in the EV Tracker turned out to be pretty close. Will use that again for future trips, although the preference would be no box at all when possible. I had one long stretch where the box made the difference between going along at normal speed, to going along about 5MPH below the speed limit and getting everyone behind me on a 2 lane road ticked off.
     
  9. aesculus

    aesculus Still Trying to Figure this All Out

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    You can try EVTO. which handles all of this and has a powerfactor that you can use to adjust for yout box too.
     

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