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Rated vs Actual @ 291 wh/mi

Discussion in 'Model S: Battery & Charging' started by russman, Aug 28, 2015.

  1. russman

    russman Member

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    So I've never been able to really get below 300 wh/mi and I've heard that Rated to Actual is at around 290 wh/mi.

    But I just charged to 80% which gave me a 206 Rated charge on my S85.

    After 98.1 actual miles using 28.5 kwh and a 291 wh/mi, I'm still not getting 1 to 1 rated to actual, as the rated miles afterwards said 99 miles. So that's 8 miles.

    Am I missing something? I thought 290 was the magic number, but doesn't seem the case after this instance.
     
  2. FlasherZ

    FlasherZ Sig Model S + Sig Model X + Model 3 Resv

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    The "since last charge" doesn't count certain loads and - in my case - occasionally on trips will "lose" some data as it "sticks".
     
  3. Troy

    Troy Member

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    Hi. For S85, the Wh/mi when rated range equals to actual range is 186.4 Wh/mi. This number is calculated from 75900Wh/265mi= 286.4 Wh/mi. To calculate your rated range consumption, you only need kWh which is 28.5 kWh in your case. The calculation is: 28500 Wh / 286.4 Wh/mi = 99.5 miles rated range. However instead 99.5 mi rated range, you consumed 206-99= 107 mi rated range. You consumed 7.5 mi more rated range than expected.

    One possible explanation is that, when you read 206 mi, range mode was off but when you read 99, it was on. Another possible explanation is after you read 206 and before you read 99, you left the car parked for a while. If neither is the case, I don't have an explanation.
     
  4. RichardL

    RichardL Member

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    Seems to me, based on this conversation happening several times over the years - that each car varies slightly, maybe based on history or driving style?

    In my case I get rated = actual at 297Wh/mi and it has been fairly consistent for well over a year (calculated on long boring runs by adjusting speed so my 30 mile average was in that region and watching the estimated range on the energy app. Estimated range = rated miles when the average is 297Wh/mi)
     
  5. RAW84

    RAW84 Member

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    Wow, surprised to see such a difference.
    I
    Rated = Projected at about 308 Wh/mile for my P85D
     
  6. David99

    David99 Active Member

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    Rated range is 300 Wh/mile. The energy graph shows it clearly. There are two reason it doesn't match the miles driven even when you go exactly at 300 Wh/mile.

    1. The trip meter does not count all energy used. It doesn't count when the car is not in motion. Every red light, every time the car is parked, it uses energy that is not accounted for in the trip meter. When you see 300 you are actually using more.

    2. the rated range is based from 100% to the point where the car shuts down. It is not to 0 miles on the display. 0 miles left on the battery gauge is not when the batter is shutting itself off. There is a little more in it and they used that letter extra when they did the EPA test cycle to get the maximum possible range for the sticker.

    Rated range is definitely based on 300 Wh/mile. In the real world (for the two reasons mentioned) you won't get the actual rate range when you see 300 on the display.
     
  7. RAW84

    RAW84 Member

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    This is definitely not the case with my car. At 300 Wh/mi Projected range is greater than rated range.
     
  8. hipringles

    hipringles Member

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    I believe RAW is correct. I have pictures where my AVG is 298, with my projected being 220 miles, and rated showing 223.

    In addition I do believe the trip meter DOES show consumption @ a redlight. Every time I stop less than 30 seconds the graph will show a quick spike to 650-700 WPM.

    If I sit for like 5 minutes, the spike goes off the top of the graph and does not come back in for at least .25 miles
     
  9. David_Cary

    David_Cary Member

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    #9 David_Cary, Aug 30, 2015
    Last edited: Aug 30, 2015
    Don't forget one variable - Car model. The magic number varies from 60 to P85D. Early on when there were 2 models, life was pretty easy.

    Some Canuck seemed to mess up the units.

    Raw - you are talking P85D and OP is S85

    There should be a chart somewhere. I'll start

    P85D - Based on Raw 308
    S85 - I recall consensus was 300
    70D- from my experience 280 (or as high as 282 - but I think they kept it even at 280)

    Does 265/253 = 308/300? No. So I'm surprised the P85D consumption assumption is 308. 311-314 would fit more with EPA

    My first 4000 miles on 70D have been really close to 280
     
  10. llavalle

    llavalle Member

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    FYI guys, The 85D is rated at 290wh/mile
     
  11. David_Cary

    David_Cary Member

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    So roughly

    P85D - 310
    S85, P85 - 300
    85D - 290
    70D - 280
     
  12. Troy

    Troy Member

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    The numbers I calculated are a little different:


    Wh/mi when EPA rated
    range equals actual range
    Wh/km when typical
    range equals actual range
    Model S 60270,48194,00
    Model S 70D260,44182,23
    Model S 85, P85, P85+286,42189,75
    Model S 85D281,11187,41
    Model S P85D300,00185,12
     
  13. russman

    russman Member

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    So in reality, none of us really know....

    In my situation I was at 290 in an S85 and it was off...
     
  14. llavalle

    llavalle Member

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    If "counting the pixels in the screen" counts, my 85D's rated line matches 180wh/km. That's 289.6wh/mi.

    When using the "when estimated range equals rated range", mine works when it's showing 180wh/km... so also 289.6wh/mi.. not sure where your 281.11 number comes from.
     
  15. Troy

    Troy Member

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    It came from this calculation: S85D= 75900 Wh/270 mi = 281.11 Wh/mi

    75900 Wh = Usable battery capacity of 85 kWh battery pack before rated range goes into minus. The source for the 75.9 kWh number is this page (scroll down to middle):
    http://nickjhowe.com/tesla/modelsguide.html

    270 mi = EPA rated range of S85D. This is well known. Tesla website and EPA website both show 270 miles rated range for S85D. However Tesla uses EPA rated range only in North America. Everywhere else they use typical range so I added that in the table above.

    281.11 Wh/mi = Wh/mi when EPA rated
    range equals actual range
     
  16. RAW84

    RAW84 Member

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    Why run a calculation when you can simply note the Wh/mi at which projected miles = rated miles?

    It's certainly not 300 Wh/mi in my P85D.
     
  17. llavalle

    llavalle Member

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    This source has been proven wrong MANY times on this forum.

    A better way to calculate usable battery power :

    1-Calculate the SOC% more accurately by dividing the rated miles left (instrument cluster) by the rated miles of the car. For example : Instrument cluster shows 150miles. 85D is rated 270miles. 150/270 = 0.55555555.. aka 55.555555%

    2-Open up the energy usage app on main screen. Multiply the "AVG Wh/mi" by the "estimated mile left"... For example 124miles left with 350Wh/mi average... That gives you the Wh left in the battery : 43500wh.
    AKA : if you continue to consume 350Wh per miles.. you'll drive for another 124miles... meaning you have 43500Wh left on the battery.

    3-Simply calculate the ratio. If 55.5555% is 43500Wh.. of is 100% ? 100% * 43500Wh / 55.5555% = 78 300Wh

    4-78 300Wh for 270 miles = 290Wh/mile rated.

    On step 2, you can switch to the different "last XX" miles estimate and redo the calculation...

    Exactly.


    See my post for more details :

    First road trip with the car - weird range behavior - 85D
     

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