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Watts per mile - Typical values versus speed?

Discussion in 'Model S: Battery & Charging' started by Asciidv, Feb 25, 2016.

  1. Asciidv

    Asciidv Member

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    Location:
    Ponteland, Northumberland, England
    Is there any tables which show typical watts/mile against speed?

    Is 300 watts/mile really achievable for typical everyday driving. From my first 3 weeks of Model S driving 400 watts per mile would seem far more typical..
     
  2. cpa

    cpa Active Member

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    Location:
    Central Valley

    In a word, yes. I have averaged 284 wh/mile over my 27,000 miles. There is a frequent contributor here from Texas whose average (if memory serves) is around 245. I live in the Central Valley of California that is over 450 miles long and gains only about 700 feet of elevation in either direction from the San Joaquin/Sacramento River delta to the mountains to the south and north. I drive at or beneath the speed limit on the highway (generally 65 or 70.) I accelerate gently and take advantage of the regenerative braking. Most of my driving has been on the open road. Finally, the weather here stays between 40-105 degrees for most of the year, with few hard freezes, and precipitation is (especially of late) spotty.

    Urban driving with quick acceleration and hard braking will increase your wh/mile. Use of the cabin heater will increase wh/mile.

    As far a tabulated compilation of speed vs. energy consumption, I think that there are a few lurking about, but I do not know where to look to find them.

    Enjoy your car! :smile:
     
  3. ecarfan

    ecarfan Well-Known Member

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    Location:
    San Mateo, CA
    In 40K miles of ownership I have averaged about 320wh/m I live in a hilly area. Climate is mild m
     
  4. Asciidv

    Asciidv Member

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    Location:
    Ponteland, Northumberland, England
    Cps, thanks for the detailed reply. At the moment here in England the temperature in the mornings when I go to work is in the 30's usually with frost on the windows. Do you think ambient temperature plays a significant part in power consumption?

    i am enjoying my Tesla. I drive it everywhere just for the sheer pleasure of driving something so unique and advanced. There are relatively few of them here in the North of England so nobody knows what it is. It is so easy to play at "Hooligan' when the tearaways pull up alongside you at the traffic lights in a Subaru Impreza with exhausts the size of drain pipes.

    ....so now you are going to say that is why I am averaging 400 watts/mile......

    Best wishes from a cold England.
     
  5. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

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    Texas
    Yes it does, but you can mitigate that by:

    1. Set the timer so that charging ends about the time you leave.
    2. Charge with range mode off, drive with range mode on (most effective for short trips).
    3. Pre-heat the car using the App.
    4. Make sure the tires have some air in them. (gases shrink in cold).
    5. Cold air is denser so there is more aerodynamic drag, moderate your speed.
     
  6. ArtInCT

    ArtInCT Always Learning

    Joined:
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    Location:
    Southern Connecticut
    As far as I know there is no such table in existence. However this is one item that I plan on generating once I have my car.
    My plan is to essentially create 4 such tables which are going to be seasonal in nature.
    December - February, March - May, June - August and September - November.
    The use of HVAC and the effects of climate on the traction battery lead me to think that I should start with four seasonal views of the wH/mile.

    This leads to the next question? What data to capture, and which app or hosted app to use?

    Frankly I was thinking of making it simple and trying to understand for each traction battery percentage, what mileage can I expect to achieve in this season?

    I plan on using my S as a normal car. Yes I will pre-heat or cool before leaving home but that is about the extent of special treatment I will go for.

    ARTinCT
     
  7. Max*

    Max* Not Banned

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    Location:
    NoVa
    17k miles, lifetime average 324wh/mi.

    An average is a bad number though, because you're averaging (well I am) bumper-to-bumper city driving where my wh/mi might be closer to 450-500wh/mi in the winter and summer roadtrips where my wh/mi might be closer to 260-280wh/mi and winter roadtrips where my wh/mi might be closer to 300-330wh/mi.
     
  8. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    Location:
    Colorado
    Sorry to be a "Unit-Obsessive" engineer, but would a Moderator please change the title of this thread to "Watt-hours per Mile - Typical Values versus Speed" ?

    Watts are units of power, and Watt-hours are units of energy.
     
    • Informative x 1
  9. dandelot

    dandelot Member

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    Location:
    San Francisco
    Low tire pressure costs watt-hours too. Down 5psi costs 10 percent, very-approximately.
    And low temps means lower pressure, so ... Know your tire pressure.
    (Don't ask...embarassing. Back at 45psi now around 300 wh/mi. Here where just
    going anywhere means up/down 400 feet altitude over and over.)
     
  10. dgpcolorado

    dgpcolorado high altitude member

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    The Western Slope, Colorado
    +1! (Retired scientist here...)
     
  11. Zextraterrestrial

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    wheels and tires make a big difference in Whr/mi at speed.
    the Pzero nero tires I have on right now seem much worse than the Goodyear AS2 tires were for energy use
     
  12. mmccord

    mmccord Member

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    Location:
    Pine Bush, NY
    The biggest single factor, in my experience, is temperature. I got my car in May and averaged about 290wh/mi for the summer/autumn. My avg in the winter is between 350 and 400wh/mi, >400 on particularly cold days.

    9a4bd19f1c066c586148612bd2050c03.jpg

    This is from my commute one day this week. The high temp that day was about 30F.
     
  13. mhs

    mhs Member

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    Not on a P. And It depends where you live (and how you drive, but I would anticipate driving style will average out). In Maryland, where we have mid-hot summers and mid-cold winters, and only small hills, I am seeing an average of 349 w/m over 18000 miles and all 4 seasons on a p85d, 21"
     
  14. GeoRover

    GeoRover New Member

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    Did you generate that data? I am interested in looking at it if possible?
     
  15. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

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    I'd rate them as follows:

    1. Driving style.
    2. Trip distance, terrain, traffic, and the number of stops per mile.
    3. The combination of temperature, weather (snow or rain on the road, and wind), and HVAC
    4. Tires, tire pressure, and alignment
    5. Road construction material

    For 2, 3, and 4, the order can change depending upon which one is the furthest from ideal.
     
  16. Solarmeadow

    Solarmeadow New Member

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    Location:
    Indian Hills, CO
    Over 25,000 miles I'm averaging 249 watt-hours per mile. I live at 7520 feet elevation in Colorado and winter temps get to 0. I stay below the speed limit, anticipate and slow down for traffic lights and roll through stop signs when safe. I use the "don't walk" sign to telegraph when I'm going to miss the light, then slow to 15-25 so I can maintain some momentum for when the light turns green. The less one's speed varies in a trip, the lower the energy consumption. It's costly to stop and start again from 0. That heavy Model S has a lot of inertia. I'm not going to save the planet but can do my share while it's a fun pastime on my commute. :) P.S. It always amuses me when people roar by in their gas hogs only to hammer their brakes for the upcoming red light. At the same time it's depressing to think about how much energy we waste with stupidity.
     
  17. Missile Toad

    Missile Toad Member

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    Location:
    Houston
    Flat (700' max elevation), dry, temps > 65º F, 2 or fewer passengers, and calm conditions in my S70D, 2015 'classic'. Measurements taken for > 10 mile stretches:
    MPH..... wh/mi
    70 ..... 287
    73 ..... 306
    78 ..... 332
    83 ..... 359
    Potential sources for error: drafting; varying road surfaces; light variable winds; tire pressure. Note, all of these were in a straight line, so elevation might have changed by 50 feet. I have made measurements that involve a loop that doubles back on a highway -- but that entails a speed drop to about 20 MPH, and the corresponding coast/accelerations.
     
  18. clostridium

    clostridium Member

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    Thanks for taking the time to do this

    These seem a bit high based on my experience - in longer road trips I'm averaging 260-280 where the average speed over the whole trip is 70 and 3/4 of that trip is highway travel with speeds averaging 75-77 mph. What size wheels do you have?
     
  19. fasteddie7

    fasteddie7 Member

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    Location:
    uniontown PA
    7E4072B1-D82F-4383-8B06-A1A6349696B7.JPG My commute is 85 miles round trip, I average 199 wh/mi during that trip. Backroads, max 55 mph.
     
  20. Missile Toad

    Missile Toad Member

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    Location:
    Houston
    I've got 19" wheels
     

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