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P85D range and highway battery performance

Discussion in 'Model S: Battery & Charging' started by Firewired, Dec 15, 2014.

  1. Firewired

    Firewired Member

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    As a soon to be owner of a P85D, when I heard the announcement for the P85D and read the initial anticipated range from Tesla. I thought that the P85D was the perfect car, all the performance one could ever want with even more range for long distance highway travel. Since the EPA results with the combined driving, the true efficiency of the dual motor for highway travel is one of the things that I have become concerned about. The EPA numbers seem contradictory with lower combined mileage, but still better MPGe on the highway than the single motor P85, but still with the rated 245 range. So now that owners are beginning to receive their cars (hopefully me next week.). I would like to propose a thread where we can list our highway miles and what kind of efficiency we really got. By doing this in aggregate, collecting all of our data we will have a lot more useful information quicker than we could if we each tracked our own individual performance. I would ask that you list highway trip data and include temp, if it was raining, snow, if you have 19 or 21" wheels, performance or snow tires, etc... and any other suggested factors people can recommend. I hope the numbers are closer to Tesla's than the EPA's.

    Thanks
     
  2. EV_Steve

    EV_Steve Member

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    Good idea. I too am having some concerns considering I'll be doing a 1200 mile road trip weeks after delivery. I'd like to suggest that we also include elevation changes in the data gathering.
     
  3. Firewired

    Firewired Member

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    I would like to propose a google spreadsheet in which people can enter their information contemporaneously from each discrete uninterrupted highway trip. That way we can compile a bunch of increasing datasets in which to analyze what the car is really capable of long distance. I have started formatting a sheet with the following columns below. 1. Does anyone have a suggestion for any additional columns I would rather just have enough and not too much, to discourage people from logging info 2. Is there anyone that has a lot of google spreadsheet experience willing to volunteer and help me with the formatting, as well as setting up the additional tabs that list the compiled aggregate data as it is input?

    Username
    Trip Date
    Distance
    Temp
    Average Speed
    Wh/mi
    Total Energy(kWh)
    Elevation change (if know)
     
  4. Saghost

    Saghost Active Member

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    Wind. Rain/snow.

    Also, it might be wise to ask for data from P85s and S85s at the same time - easier to get Apple to Apple comparison with all homogenous data.
    Walter
     
  5. Zextraterrestrial

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    ...and wheels and tires make a HUGE difference. + air density of location-coastal vs midland

    overall elevation change is important but driving in constant hills does add a little hit too
     
  6. MarcG

    MarcG Active Member

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    #6 MarcG, Dec 16, 2014
    Last edited: Dec 16, 2014

    That's a great idea! And I'd be glad to help out with #2.

    I got my P85D last Friday and took a day-trip to Tahoe on Sunday - see this thread for all the details:
    First SF-Tahoe trip in P85D

    In the table I put together, I had some of the variables you suggested. Temperature is tricky since it could change quite a bit on major elevation changes.

    FromToActual DistanceRated Miles UsedAvg SpeedNet Altitude Change
    San FranciscoRoseville SC110 miles144 miles75 mph-92 feet
    Roseville SCSugar Bowl73 miles150 miles70 mph6790 feet
    Sugar BowlRoseville SC73 miles42 miles60 mph-6790 feet
    Roseville SCSan Francisco110 miles138 miles65 mph92 feet
    However in late December I am planning a long road trip to Oregon that will cover over 1500 miles total, so I should have much more data then.
    So let me think about what variables are easy to collect on a frequent basis.
     
  7. ArtInCT

    ArtInCT Always Learning

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    Payload? Total weight in Car, estimated.
    Mode, Sport or Insane.
    Regen mode..
     
  8. mkjayakumar

    mkjayakumar Active Member

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    Average speed parameter is a bit tricky and I am not sure how Marc calculated. If it is from the trip computer then maintaining an average speed of 75mph for such large distances would necessarily mean there have been long stretches he drove in excess of 80 or 85 mph, to compensate for stretches that were driven less than 60 or even 50. And that kind of driving will consume much more energy than driving a steady 75mph, which is almost impossible.
     
  9. MarcG

    MarcG Active Member

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    FYI, the 75 mph I got was by leaving SF at 5:30am and driving to Roseville with very few other people on the road. So it was easy to drive at a constant 75 mph for 110 miles! There were only a few minutes when I wasn't driving at highway speeds (getting onto 101) but it didn't impact the average since it was only for less than a mile.
     
  10. Andyw2100

    Andyw2100 Well-Known Member

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    Maybe it should be made clear that instead of a true "average" speed for the trip what would be more useful would be the speed one was generally cruising at. If someone varies quite a bit, they'll have to take their best guess at it, but if most of the trip is spent on the highway, doing 70 MPH, and a few minutes are spent at either end, in traffic, etc, or just at much lower speeds, isn't it really the fact that the bulk of the trip was spent doing 70 that will be most helpful?
     
  11. Firewired

    Firewired Member

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    OK, All are good suggestions and would be very interesting.

    The premise of my original post was to see if the P85D would approach the higher numbers originally posited by Tesla for steady state highway driving (I Hope) versus the final released EPA for combined driving. I would like to keep it as simple as possible to try and answer this one question, and encourage as many people to try and log data for single uninterrupted stints of highway driving in their P85Ds. The more datasets people contribute the better the opportunity for analysis and more likely to come up with a valid answer.

    Here is the simplest, quick to fill out google doc I could come up with:

    https://docs.google.com/spreadsheets/d/1x1e2h_MwAT73QX25hw-FyaYWfBcx5E_OzBdS8Xn0TOo/edit?usp=sharing

    Thanks
     
  12. crazybrit

    crazybrit Member

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    While we could go crazy adding columns, I have found the greatest factor that influences range after elevation is wind. Head, tail, or crosswind. It isn't easy to gather the data, but I get the local weather as I am traveling, then average it out. A wind at 45 degrees to the direction of travel seems to affect range the most, I think is is because it destroys the aerodynamics.
     
  13. dsm363

    dsm363 Roadster + Sig Model S

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    It seems to me that setting cruise control at 65mph and seeing how far you can go would be the only way to see if Tesla was being accurate. Along with all the other factors mentioned above this will be difficult to get the information people are looking for.
     
  14. Andyw2100

    Andyw2100 Well-Known Member

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    How about if we have asked Firewired to add some sort of column to the spreadsheet for a user to check if and only if the data he/she is entering for the trip meets certain "perfect trip criteria" guidelines. We can still gather all data in the spreadsheet, but then we could easily pull out only that "perfect trip" data to look at it to see how it compares to Tesla's numbers. The criteria for the "perfect trip" data would probably have to be things like speed consistently 65 MPH, no excess weight in car, no significant wind, no significant elevation changes, temperature between x and y, etc.
     
  15. crazybrit

    crazybrit Member

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    I like this idea. Although I don't think I have ever had one of those!
     
  16. Denarius

    Denarius Active Member

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    In the wheels column you don't have an option for the stock tire option 21" Summer Tire, the P85D does not come delivered with a "21" All Season."
     
  17. MarcG

    MarcG Active Member

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    I really think net elevation change should be a mandatory field for each trip recorded.
    Even a few hundred feet will make a difference and it's really easy to get this data from evtripplanner.com
     
  18. Danal

    Danal electricmotorglider.com

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    Anyone with a P85D willing to use a Geo-Tracker? There are many brands out there, some of them pretty cheap.

    That would leave only wind. Which, with dates, could be retrieved from the National Weather Service.
     
  19. CRASCH

    CRASCH Member

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    interesting info in this article.


    2014 Tesla Model S P85D: First Drive Of All-Electric AWD Performance Sedan...


    "But this lower number is due solely to an odd new EPA procedure that slaps a 10-percent range penalty on any electric car that has driver-adjustable charge settings. (Don’t ask.)"


    That explains the 242 and puts the actual rated range at 269...


    I hope Tesla changes their rated range calculation for the car. I'd like to actually be able to adjust it back to the normal position where a full charge at rated would read 269. Or even better set my own WH/M.
     
  20. jerjozwik

    jerjozwik Member

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