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EPA rates Model S at 89MPGe with 85 kWh pack

Discussion in 'Model S: Battery & Charging' started by Discoducky, Jun 20, 2012.

  1. AnOutsider

    AnOutsider S532 # XS27

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    89... I'm no expert but when I was doing some calculations (1 gallon of gas in 33 kwh of energy is it?) I got much higher. Though I guess that was using a higher real world range too.

    *edit* someone can correct me if I'm wrong, but if the number I was working with (33 kwh == 1 gallon of gas) is correct, then an 85 kwh pack that goes 265 miles on a charge uses up .32 kwh per mile. So with 33kwh in a gallon, you'd get 33 / .32 = 102ish, closer to 103 mpge...
     
  2. gg_got_a_tesla

    gg_got_a_tesla Model S: VIN P65513, Model 3 Res Holder

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  3. dsm363

    dsm363 Roadster + Sig Model S

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    When they (Fueleconomy.gov - 2012 Tesla Model S) say
    Cost to Drive 25 Miles $1.14

    what cost/kWh are they using? They don't seem to say.
     
  4. BYT_P1837

    BYT_P1837 Member

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  5. Grendal

    Grendal Active Member

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  6. Kipernicus

    Kipernicus Model S Res#P1440

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    Doesn't 89 seem low, compared to the 99+ of Leaf and others?
    The EPA must have been flooring it!
     
  7. Discoducky

    Discoducky Active Member

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    Still, this seems way low. According to this it's 38kWh/100 miles. So the 40kWh battery might only go 110Miles? I was expecting it to be closer to 130Miles. Also, I don't see how city and hwy #'s are that close.

    compare.PNG

    I do like the $$$ savings though!
     
  8. gg_got_a_tesla

    gg_got_a_tesla Model S: VIN P65513, Model 3 Res Holder

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    And, given 38 kWh/100 miles, how does the 85 kWh pack give 265 miles? Isn't it only ~223 miles?!
     
  9. Todd Burch

    Todd Burch Electron Pilot

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    Regardless of whether the number is right or wrong, remember the Model S is *much* bigger than the Leaf. Much more battery = heavier than the Leaf.

    Still, not too shabby given 0-60 in 4.4sec...
     
  10. drees

    drees Active Member

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    Sounds about right. The Model S is a heavy car with huge wheels/tires compared to the other EVs on the market. 89 MPGe is very good for this car.

    City efficiency isn't higher because of the high weight. Highway fuel efficiency isn't higher because of the big wheels/tires.

    Also remember that the kWh/mi ratings from the EPA are from the wall and include charging losses. So according to the EPA if you put 37 kWh into the car, you'll go right around 100 miles. The LEAF where you can only stuff 24-25 kWh into it from the wall, will do about 73 miles freeway. So Telsa's estimate of 265 miles EPA range for the 85 kWh Model S is about right. The 40 kWh Model S should have about 120 mile range.

    Anyone else notice that the EPA site lists the Model S as having a 83 kWh battery, though?
     
  11. gg_got_a_tesla

    gg_got_a_tesla Model S: VIN P65513, Model 3 Res Holder

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    Yeah. Surely data entry error.
     
  12. richkae

    richkae VIN587

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    Remember that their numbers are wall to wheel. So 38kWh if the charging is only 90% efficient, only puts 34kWh into the battery.
    Even if the charger is 90% efficient ( I made that up, I don't know what it is ) there is likely additional overhead due to cooling.
     
  13. Todd Burch

    Todd Burch Electron Pilot

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    I don't want to get too far off topic here, but isn't that really "unfair", given that MPG is tank to wheel?

    Edit: I mean in a sense when comparing to an ICE.
     
  14. Lyon

    Lyon 2016 S P100DL, 2016 X P90D

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    The article also makes a pretty big error is stating that the Model S has the worst MPGe rating of any electric car. The Coda Sedan got 73.

    CODA_EPA_MPGe.jpg
     
  15. richkae

    richkae VIN587

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    Not when the purpose of the number is to determine your fuel cost.
     
  16. Todd Burch

    Todd Burch Electron Pilot

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    Touché.

    Why would an American consumer be interested in that? :)
     
  17. stopcrazypp

    stopcrazypp Well-Known Member

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    The efficiency number (38kWh/100miles) includes charging losses. You can't use that number with the battery capacity to figure out the range. That's why the math doesn't work out if you just divide battery capacity with the range. From the EPA page they give the battery capacity only a 83kWh rating (maybe that's the usable capacity).

    http://www.teslamotorsclub.com/showthread.php/8252-EPA-range/page2?p=131711&viewfull=1#post131711

    Anyways, 83kWh/265miles = 31kWh/100miles. So charging efficiency's only about 31/38 = 81.6%.

    Anyways, the 89MPGe is what Elon said in a recent conference call. They are trying to get a better number by improving the charger.
    http://www.teslamotorsclub.com/showthread.php/8562-How-to-calculate-the-cost-to-charge/page2?p=140284&viewfull=1#post140284
     
  18. gg_got_a_tesla

    gg_got_a_tesla Model S: VIN P65513, Model 3 Res Holder

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    Thanks, stopcrazypp. I've got to digest your detailed post on that other thread.
     
  19. tdelta1000

    tdelta1000 Active Member

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    + 1 :)
     

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