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New 6.1 Trip Chart feature takes the guesswork out of winter range

Discussion in 'Model S: User Interface' started by ToddRLockwood, Feb 3, 2015.

  1. ToddRLockwood

    ToddRLockwood Active Member

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    #1 ToddRLockwood, Feb 3, 2015
    Last edited: Feb 3, 2015
    We had a cold morning here in Burlington, Vermont. It made me wonder whether I could make it to the new supercharger in Hooksett NH if I had a reason to head down to Boston soon. I've made this trip numerous times in the warm half of the year, but I've never attempted it in the winter. Hookset is 60 miles closer to me than Boston, but with the temps in the 10-15 degree range, I wondered whether that 60 mile credit would evaporate along the way.

    Here's a photo of my P85 instrument panel. 233 miles of Rated Range, and it's 18-degrees F outside.

    DSC_7464M.jpg


    I selected the Hookset NH Southbound Supercharger from the Supercharger menu in the Navigation. It's 157 miles away. Seems like I have plenty of range to make it—or do I? On the face of it, my safety buffer appears to be 76 miles, but that doesn't account for the cabin heater and the battery heater.

    DSC_7467M.jpg


    The new Trip Chart feature (a new tab within the Energy app) takes the guesswork out of these situations. Working in cahoots with the Navigation, the Trip Chart takes both the outside temperature and the route's elevation changes into account and predicts how much energy you'll have left when you reach your destination. In the upper-left corner of the chart, you can see that it's showing a starting range of 88%. (0.88 x 265 = 233) The system predicts that I will have 14% left when I arrive at the Hooksett supercharger. (0.14 x 265 = 37) 37-miles is a safety buffer I can live with.


    DSC_7473M.jpg

    You'll notice that the green line on the chart has some undulations in it. Those are changes in energy usage based on elevation changes along the route. Apparently, this elevation data has been sourced from Google. It's quite uncanny to watch this chart perfectly mirroring the ups and downs of the highway.

    I believe the prediction is based on the posted speed limits. If you start using more energy than the prediction, a second gray line will appear representing the original prediction, and the predicted energy remaining at the destination will change accordingly. You can easily bring yourself back in line with the original prediction by slowing down a bit. The system is self-correcting in real time and shows you exactly where you stand at any moment. Pretty cool!

    Finally, when doing any distance driving, winter or summer, don’t forget to turn on Energy Saving mode in the Vehicle Controls. This will reduce the amount of power used by the heater/air conditioner as well as by other parts of the car.


    (Corrected per stevezzzz's comment below)
     
  2. stevezzzz

    stevezzzz R;SigS;P85D;SigX

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    I agree, the Trip chart in the Energy app is the bee's knees.

    But you got the bit wrong about what happens when you start using more energy than expected: the green/yellow/red battery SOC line falls below the gray line that represents the system's predicted use. I suspect that gray line is always there, it's just hidden when the battery SOC line matches up with it.

    As I mentioned in another thread, the prediction underestimates usage when the route is uphill and overestimates usage when the trend is downhill, but evens out in the end as long as the net elevation change is near zero.
     
  3. HillCountryFun

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    Excellent description of the process with great pics to back it up!! Nicely done and thanks!!! :biggrin:
     
  4. ToddRLockwood

    ToddRLockwood Active Member

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    Thanks for that correction. I was doing this from memory.

    You must see this over/under estimation when driving up and over some of the Colorado mountain passes. I imagine that on the downhill side, it would be effected by the regen setting.
     
  5. EdA

    EdA Model S P-2540

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    OK, 2+ years into ownership, *now* I finally regret not getting the tech package.
    Good thing the wife's car has it.
     
  6. stevezzzz

    stevezzzz R;SigS;P85D;SigX

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    Yes, the 6000' net elevation change over some of the higher passes makes the discrepancies I've described quite obvious.

    I don't think you'll see any difference in consumption based on the regen setting, unless you are forced to use friction braking to hold speed on the steeper downhills, when regen is set to Low. I haven't yet seen a hill so steep that Standard regen wouldn't hold whatever speed you might choose.
     
  7. BerTX

    BerTX Member

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    Thanks for that info. I'd always wondered about that. My hybrid doesn't quite do that, so I wondered about the Tesla. Of course the 3-cylinder Insight has to use the battery to help it get UP the hill, then going downhill the battery tends to start overheating a tad with full regen.
     
  8. RiverBrick

    RiverBrick Active Member

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    14% isn't enough of a buffer in Winter, unless you're willing to take side roads and turn off the heat. My actual consumption has been about 30% over the 6.1 predictions for Montreal/Quebec (~150 miles) when the temp has been between 0 and 10F.
     
  9. EdA

    EdA Model S P-2540

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    It takes the outside temperature into account!
     
  10. Pollux

    Pollux Member

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    @RiverBrick,

    The 6.1 predictions are working well for me; I don't know why you're having a different experience.

    My example: my recent round trip from Boston to New York City via Auburn, MA SuperCharger and Darien, CT Supercharger. At each step of the trip, I used the Nav to select the next waypoint (Auburn, Darien, NYC hotel, back to Darien, back to Auburn, back to home). I then watched the Trip energy graph, as well as the consumption energy graph (selected as a constant dashboard display rather than on the center console). I noticed that I was using a lot of energy, bouncing around from as low as ~280 wh/mi to as high as >600 wh/mi. But at the end of each trip segment, I arrived at the destination with the amount of remaining charge predicted by the trip software OR within a couple of percentage points. Always LESS energy than predicted in those cases where I didn't hit the original target. But then again, my trip was in <20 degree Fahrenheit weather, and I went roughly 65-80 mph for nearly the entire trip. With cabin temps set to 67-68 degrees (me) or up to 70 degrees (The Wife).

    At each SC stop, I used the nav to look at the charge estimates to the *next* stop, which heavily influenced my thinking about how long to stay at the SC. Previously, I pretty much just charged to a max charge each time, because I wasn't *that* confident about how large a buffer I needed.

    Effectively, the trip planning software was doing for me what I used to do manually: calculate the number of real miles between way points, figure out how large a buffer I thought I'd need given weather conditions and any other factors, then decide how much I needed to charge at each waypoint.

    And, when The Wife got hungry and we detoured 10 or 15 miles to find a decent place to eat, the Trip energy graph and prediction of target SOC gave me confidence that we wouldn't wind up sitting at the side of the road waiting for a tow truck.

    I think the biggest decision you need to make given this new software is whether you want an additional buffer to take into account random side-trips. If you're just going point-to-point, the software is working pretty well on the prediction side... and the real-time updates means that you can see a problem coming (yellow/red) before you get there, and can adjust your driving habits accordingly.

    Unless, perhaps, there's some magic break point in the prediction software that can handle well the temperatures I experienced (a rough range of 15-25 degrees F over the entire 30-hour trip) but falls down at the temperatures you're encountering.

     
  11. bob_p

    bob_p Member

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    Drove a trip over the weekend, and overall the new trip estimator worked well - except for one segment when I was probably driving into a strong wind, and the estimated range when I would arrive at the next supercharger dropped 5% in about 10 miles.

    What I found most useful was to continuously display the projected destination remaining charge on the navigation map rather than wasting half the screen to display the trip chart. Tesla should remove the round trip projection or at least require an extra screen tap to display it.

    By monitoring the rapid loss of destination charge - I was able to slow down earlier and maintain a reasonable speed.

    As a first release - it's a useful tool - though it could be improved with some additional features.
     
  12. reuted

    reuted Member

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    Last Saturday we took a 1st trip from Chicago to Preoria and back in our new car. I found the new prediction to be exceptionally accurate. The actual range was materially reduce from cold temps. I underestimated the reserve necessary. However we managed to pull into the super charger In Normal IL twice with zero remaining range. The 2nd time I had to switch the car heat off and reduce speed. But the accuracy of the prediction was remarkable and accurate to a few miles.

    The other teaching point to myself and our boys was so very practically see how energy consumption depends on speed. I would never have dreamt of driving at 60 but that is what was suggested by the prediction algo and it made a big difference vs driving at the 70 percentile of everybody else on the road. Amazing Car and supportive analytics.
     
  13. Andyw2100

    Andyw2100 Well-Known Member

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    Check this relatively new thread for a webpage you can bookmark that will give you instant information on the wind conditions you are experiencing. I used it for the first time today, and it seemed to work very well.

    Tool to estimate the head wind while driving !
     
  14. TexasEV

    TexasEV Active Member

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    I have always displayed the energy app on the right side of the dashboard screen. Is there a trick for it to show the new trip tab of the energy app there instead of the energy consumption graph?
     
  15. RiverBrick

    RiverBrick Active Member

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    How does it compute the outside temperature? Does having the car in a heated garage or use of HVAC throw the system off? Does 6.1 take into account if you're using Winter tires will higher rolling resistance?

    Twice, 6.1 said I would have ~35% remaining for Quebec City/Montreal. The speed limit is 100 km/hr, but the average car goes around 113 km/hr. In both instances, I started out at 107 km/hr, but slowed down to 100-103 km/hr and arrived with about 5%. Heat set to roughly 22C, but perhaps 6.1 didn't anticipate this since no heat was used in the garage before departure.
     
  16. EdA

    EdA Model S P-2540

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    Don't set your destination until you leave the garage? Interesting "bug" though.
     
  17. Saghost

    Saghost Active Member

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    I don't think anyone really knows for certain, but from what I've read I don't think it uses the outside temperature itself at all. However, the estimate clearly changes with the weather.

    What some earlier posts suggested is that it uses current or recent past energy consumption/efficiency to protect the chart - which would thereby include your HVAC use from the weather.

    This approach is much simpler and reliably whacks a bunch of variables at the same time - but it makes prediction prior to starting the trip difficult and can be tripped up by weather changes during a trip.

    I'm not certain how Tesla adjusts the initial estimates - or even that this is how they factor in weather, though it seems to fit the data.

    My suggestion when I was describing doing something like this had them grabbing cyrrent weather/forecasts for the current location and the path to the destination from the Nav system and using the HVAC and speed limit assist settings with the weather to calculate.

    It's be interesting to see Tesla apply some neural net programming here - the car knows both what it predicted and the actual result, and some simple analysis would show what was causing the prediction error - Tesla could make the prediction a learning function that gets more accurate over time as it discovers your driving style and habits.
    Walter
     
  18. ToddRLockwood

    ToddRLockwood Active Member

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    Interesting question. I just tried it. It is not possible to display the Trip Chart in front of the driver—only on the touch screen. There is an advantage to this: you can simultaneously display the Energy Graph in front of the driver, while also displaying the Trip Chart on the touch screen.
     
  19. bob_p

    bob_p Member

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    Displaying the trip destination charge prediction on the dashboard would be useful. Considering how little information is in the new trip chart - it's a waste having it tie up 1/2 of the touchscreen display.

    It is possible to display the destination charge in the navigation display - though it would be much more convenient to have the destination charge on the dashboard.

    Over the weekend, I hit some headwinds during a trip - and lost about 5% of predicted range in only 10 miles - and started monitoring the trip display closely until I could slow down the energy loss - and ensure I had adequate cushion to reach the next supercharger.
     
  20. Saghost

    Saghost Active Member

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    I like this idea - once Tesla has confidence in the estimates, make it part of the navigation status data block - put on both the large and small navigation screens the distance to destination/waypoint, ETA, and estimated charge/range remaining at destination/waypoint.Walter
     

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