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Real Usable Battery Capacity

Discussion in 'Model S: Battery & Charging' started by Capacek, Apr 29, 2014.

  1. Capacek

    Capacek Member

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    Hi Guys,

    i am sorry if it is clear for everyone, but can you tell me the real usable battery capacity for P85 Model S?
    I can see in several videos and pictures maximal 68 kWh on a single charge - can you post pictures with more kWh used?
    On my Model S i made max. 54 kWh with rest only 25km available, but it was not only one trip but whole one week.
     
  2. Kalud

    Kalud Member

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  3. golfski

    golfski Member

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    Is there a similar diagram for the MS60?
     
  4. Dylan

    Dylan Member

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    4a2e7a4y.jpg

    And still some energy left in the pack ;)
     
  5. glhs272

    glhs272 Unnamed plug faced villian

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    Rhinelander Trip photo.JPG

    hmm... I would assume then the 60's must have less bricking protection reserve.
     
  6. abasile

    abasile Independent Software Eng.

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    Nice diagram. Where did you find it? I wonder if the EPA range figure of 265 miles (85 kWh) was achieved using the "Zero Mile" Protection reserve. My guess is that the rated 265 miles involves using the battery from full charge to shutdown aka. "turtle".
     
  7. Muzzman1

    Muzzman1 Member

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    #7 Muzzman1, Apr 29, 2014
    Last edited: Apr 29, 2014
    I'm just guessing here:
    Based on 280Wh/mi (EPA Rated rate of discharge) with 75.9Kwh Range charge you'd get 271 miles, so it doesn't look like the EPA estimate dips into the "0" Range.

    My 1st range charge at about 1200 mile 2 week old car:
    IMG_6984.JPG
     
  8. abasile

    abasile Independent Software Eng.

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    I'm puzzled. Why would the display show 271 rated miles if six of those miles are "below zero"? Isn't the "zero mile reserve" supposed to be hidden from the driver so that he/she won't plan to use those miles of charge?
     
  9. Vger

    Vger Active Member

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    Most Model S's have shown a slight excess over the rated 265 miles RR when brand new. That excess tends to go away within a few months. The very first part of the cell aging (first 10 cycles or so) is more rapid than what happens during most of the life of the battery.
     
  10. Muzzman1

    Muzzman1 Member

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    @abasile: My Car's rated range is 271 because it is brand new. As I described in the post above. With a new battery that has 75.9Kw available charge, a perfect scenario, with EPA rated consumption of 280Wh/mi [75.9/.280=271] you get 271 miles on a range charge. After the slow degradation of the battery over time, or firmware changes in recalculations, that number will decrease from 271.

    EDIT! I changed my values above as I typo'd my math. It is 75.9 usable KW
     
  11. Capacek

    Capacek Member

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    Really really thanks guys,

    specially thanks Kalud for his diagram and Dylan for his photo!!!
     
  12. Kalud

    Kalud Member

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    I get a bit too much credit, I actually got the pic from here:
    Tesla Model S Buyers', Delivery and Owners' Guide

    I think that every new owner come to the same steps. After 5 months and 10,000 km I can tell you that what's really matters is knowing how far you can really drive given the conditions and plan to keep a buffer. After 25 km or so your average will get obvious and you can then compare your real distance to destination (GPS) to the projected range on the energy graph (set on average, not instant). This way you can gauge your buffer all the way and adjust your energy consumption accordingly (speed mostly then heat).

    Then after a couple long trip in different condition, it gets quite a second nature and you won't think too much about it... Just need to plan where you'll charge and try to always have a plan b ;)
     
  13. Capacek

    Capacek Member

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    Thanks again for the very interesting source page.....btw. i can see that we have same configuration of our Model S (only rear seats is missing in mine)
     
  14. mgboyes

    mgboyes Member

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    The EPA rated ranges for cars are calculated by taking the results of various different test runs and using some algorithm/formula to combine them together. But I'm fairly sure their individual test drives keep going until the car actually stops, not until its gauge reads empty. Otherwise car makers would be incentivised to leave the smallest possible reserve in order to make their range figures look better. I assume they would have done the same with the Model S.
     
  15. David99

    David99 Active Member

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    For the most part battery capacity is measured in Ampere-hours (Ah) which makes it easier as the voltage changes under load. Of course voltage also matters as well. It matters in a way that at lower load you can get more Wh out than under high load yet at the end in both cases the battery has the exact same state of charge! I know it makes no sense at first.

    The voltage is higher at a lower discharge rate and lower and a higher discharge rate. A 200 Ah battery can be discharged for 2 hours at 100 Ampere or 20 hours at 10 Ampere. At the end the battery is empty in both cases, but the voltage has been higher as it was discharged at a lower rate. As a result you get more Watt-hours.

    So far the max I was able to get out of the 85 battery going 2 miles passed 0 miles was 76.5 kWh.

    - - - Updated - - -

    5 weeks
    6k miles
    using Superchargers mostly
    still getting 271 rates miles
    :)
     
  16. ljwobker

    ljwobker Geek.

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    What is the consensus (if any) on using the capacity that lives between the 75.9 and 81.1 kWh thresholds? I'm looking primarily for how much of this is:

    "We don't want customers running out of juice and calling us dirty names"

    compared to

    "Driving the battery to this level of charge has significant impact on longevity, etc"
     
  17. ElSupreme

    ElSupreme Model S 03182

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    This isn't an official Tesla graphic. So the numbers are guessed at. So they are not very precise.

    And beyond that going beyond zero isn't reliable. You could go 1-2 miles or go 10. But every foot past zero is a blessing that shouldn't be counted on. If you think you have the buffer you will end up like this:

    Ran out of juice, 12V and main pack drained, need info.
     
  18. SarahsDad

    SarahsDad Member

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    While it's not an official graphic (it appears it was constructed by NickJHowe based on data from Rod and Barbara) and "represent(s) a limited set of data collected over a week or two in one vehicle" according to the original poster, it fairly accurately predicted a finding I noted yesterday - that after a max charge driving down to 1mi remaining, I used 73.4kWh and 251.5 miles. Rated miles were 262 (max charge was 263, w 1mi remaining), with overall 292Wh/mi. This is pretty close to the 75.9kWh from the graphic, and may represent some range loss after 10,000 miles on my car.

    IMG_3345.JPG
     
  19. russman

    russman Member

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    Is there a chart that shows the battery level at each charge level on the car battery marks?

    Full charge is 100% = 70kwh
    The first notch is 90% so that = x amount of charge
    etc...
     
  20. Yodda

    Yodda New Member

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    Hi Kalud,

    Do you have this data for 60 kWh model S? I was told by Tesla that you would normally have 56 kWh to use out of 60. I saw on the fueleconomy.gov website the car gets 350 watt-hours/mile fuel economy (35 kWh to go 100 miles). SO if this is the case then the best the Model S can do on range is 56/.35 or 160 miles. this is no the 208 miles offered as the range. My friend has only been able to get 160 miles max on the highway. Anyone else here able to get 208 or higher and if so under what conditions.
     

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