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Range anxiety in the desert

Discussion in 'Model S: Driving Dynamics' started by longshadows, Oct 24, 2016.

  1. longshadows

    longshadows Member

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    Making my first road trip in an Model S-85. Left Phoenix for Palm Springs. Initially the on board Supercharge display map said I could make the trip to the Quartzsite (AZ) SC with 13% battery to spare. Then, after stopping about half-way at a rest area along I-10, the car recalculated and informed us we didn't have sufficient charge to reach the SC in Quartzsite... or return to the Buckeye SC! We weren't doing any heavy acceleration, in fact, we were using the cruise control most of the time.

    Well, we just made it to the Quartzsite SC (whew!) with "6 miles" to spare after shutting downs as much battery usage as possible and driving at 55 mph the last 60 miles. Very nerve racking, especially in the middle of the desert.
     
    • Informative x 1
  2. cmorgan

    cmorgan Member

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    That would make me nervous.

    I believe Tesla (or Elon) has said something like "you can't run out of charge if you use the navigation system", maybe they would foot the bill for a tow if you were driving as expected (if the Nav wasn't suggesting you drive at 60 mph and you were doing 80) and following its route.
     
  3. kort677

    kort677 Active Member

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    while they might foot the bill for the tow, how would you like to have to wait many hours for that tow to show up?
     
  4. cmorgan

    cmorgan Member

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    I agree. It wouldn't be wise to run out of charge by being careless. In this case it sounds like the nav system missed something.
     
  5. McRat

    McRat Active Member

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    The western high deserts and mountains play havoc on efficiency. Winds, grades, speeds, temp variation all conspire to reduce your range.

    But, it could have been worse... Don't go East from Phoenix ... :D
     
  6. pilotSteve

    pilotSteve Member

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    I made this trip twice in my S-85 and receive the "turn around" message just before the half way point. It sure surprised me because my mental math (hey I am a pilot) shows I would make Palm Springs with 10% reserve which was my plan.

    Same "false warning" when returning from Palm Springs.

    Something is screwy with the trip planner! I submitted a bug report but never heard anything (this with v7). When I got this false warning a 3rd time I rebooted both screens and the warnings stopped.

    Were you running v8?
     
  7. bkp_duke

    bkp_duke Member

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    Had something similar happen once. Wound up drafting off a Semi for 60 miles (was GREAT to see < 200 wh/mi), but would not recommend that rountinely due to possibility for damage due to rock chips.
     
  8. AmpedRealtor

    AmpedRealtor Banned

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    Look at the Trip graph in the Energy app. That's a handy way to determine if you are going to make it to your destination. If your actual trip line is below the reference line from Tesla, you are using more power than Tesla anticipated for your trip. Simply slow down or otherwise change your driving style to bring your trip line back in line with Tesla's. If you are above Tesla's line then you are doing better, so no worries.
     
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  9. RichardL

    RichardL Member

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    I always give myself at least a 20% reserve. It appears the nav calculations watch your usage versus the calculation and then apply the deviation to the entire trip.
    As an example, I charged at Tejon Ranch, for Cabazon and has a predicted reserve of around 23% as I left. On the first few miles, up the Grapevine I was doing around 70 and the prediction plummeted to negative, with a slow down message. Once I reached the top and started to descend it slowly improved and I arrived with 20% as hoped.
    You see the same issue when leaving a supercharger, the nav acts as if you are cruising Immediately, but the initial turns and accelerations effect the calculation and then Slowly recover.
     
  10. sdorn

    sdorn Director of Awesome

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    My Leaf comes with roadside assistance standard, and it includes getting towed as a result of running out of power. I would be surprised if Tesla didn't have a similar benefit. Pretty much every roadside assistance service covers running out of gas for ICE cars as well (although that wouldn't typically require a tow).
     
  11. kort677

    kort677 Active Member

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    that's great for LAEF owners, do they have a shorter wait time than telsa owners for that tow truck when stuck in the middle nowhere if they run their battery down to nothing?
     
  12. tomas

    tomas Traded in 9 rep bars for M3, used to be somebody!

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    What speed was your cruise set at? 13% not much leeway, and if you were going 75 into a headwind you can use that up in a hurry. I have energy trip graph on 100% of the time when estimate at destination < 20%. That way I see a trend fast!
     
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  13. jaguar36

    jaguar36 Active Member

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    How did it recalculate? Did it choose a different route or something? I've never had it just recalculate the energy usage, usually the estimate just slowly drops.
     
  14. sandpiper

    sandpiper Active Member

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    I've learned the hard way that the range predictor is normally only good to within 10% and it can be lot worse. Headwinds and low temperature can throw it way off. I believe it considers elevation.

    On a long leg, I always set my destination, display the consumption graph and watch the predicted range based on the last 25km. And then I set my speed to let me get to my destination plus at least 50 km of buffer. If the buffer starts to drop below 50 km I slow down accordingly. Usually I find that I can start to push the speed up as I get closer.
     
  15. bkp_duke

    bkp_duke Member

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    Get AAA. No tow-truck needed. They show up with a L2 charged connected to an on-truck generator. You just sit there long enough to charge up to get to a real charger.
     
  16. kort677

    kort677 Active Member

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    really? how long would it take for that L2 charger truck to reach you? I be willing to say that it would take as long as a flatbed would take to reach you.
    in the scenario offered by the OP I think that the L2 would take a few hours to give him a charge like that. it might be more time efficient to be flatbedded to the nearest charger.

    Could a tesla driver depend on AAA having that capability everywhere?

    is that coverage national? did you know that most of the AAA responders are contractors? and that they don't all have such advanced capabilities?
    the fact is that while AAA does offer that service in some places it isn't offered universally and depending on AAA to come and charge you could be a big error.

    the moral to the story is that when on an extended road trip is to be aware of where your next charge is, how much charge do you need to make it to that charge, what the climatic challenges are, such as cold, rain, winds, and also be aware of subtle elevation gradients that will rob you of distance.
    you should also be aware what alternatives are available in an emergency, such as L2 chargers.
    one thing that is different about driving the tesla versus an ICE is the amount of pre planning that should occur when going on an extended road trip.
     
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  17. roblab

    roblab Active Member

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    I make that drive and similar ones twice a year, Phoenix to Napa Valley. I watch my usage as I drive, and change my speed accordingly before it gets exciting. I try to have 50 miles or more of buffer (more charge than miles required), and I keep my speed lowered, as in I drive in the truck lane. It takes a ton more of power to go 80 and 85, and don't tell me you have to go that fast or you will get run over.

    The available apps work well. The Tesla trip app takes changing elevations into account. But the driver has to be able to figure wind, rain, AC loads, etc, and to keep an eye on his buffer.

    It sounds like you took off from Phoenix area doing 80-85 and never looked at the energy graph for a hundred miles. Hopefully the experience you shared will educate many drivers to learn how their cars work and how to watch their buffer charge.
     
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  18. ecarfan

    ecarfan Well-Known Member

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    I'm sorry you had a stressful experience. Did you notice headwinds after leaving Phoenix? The nav does not factor in headwinds.

    You were smart to slow down to 55mph. The difference in energy usage between say, 70mph and 55mph is significant.

    Keep the energy usage graph up on the center display when your nav predicts less than 20% battery remaining at your next charging stop and watch the actual vs. predicted lines and the remaining range percentage as you drive. When the lines diverge take action, meaning drive slower.
     
  19. iridium

    iridium Member

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    Interesting.. my nav systems says my new 60 can make it from Scottsdale to Quartzite without charging in Buckeye. I was suspicious of this since there was no way I could pull that off in the old 60.. I probably won't risk it given your experience.
     
  20. bkp_duke

    bkp_duke Member

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