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How did they get to a 70kWh battery pack?

Discussion in 'Model S: Battery & Charging' started by ahaer, Apr 8, 2015.

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How did they implement 70kW pack?

Poll closed Apr 22, 2015.
  1. Same number of larger capacity cells

    26 vote(s)
    19.8%
  2. More cells of same capacity

    86 vote(s)
    65.6%
  3. Software change (using more cell capacity)

    2 vote(s)
    1.5%
  4. Combination of all

    3 vote(s)
    2.3%
  5. Something else

    5 vote(s)
    3.8%
  6. I don't know

    9 vote(s)
    6.9%
  1. ahaer

    ahaer Member

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    What do you think?
     
  2. Johan

    Johan Took a TSLA bear test. Came back negative.

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    Three possibilities:

    1. New cell chemistry.

    2. More cells with old chemistry.

    3. Old cells used within a wider voltage range (don't laugh this one off, IMO it's a real possibility)

    4. Any combination of 1+3 or 2+3
     
  3. ahaer

    ahaer Member

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    I think I have those three choices in the poll at the top of the page. Which one do you think is most likely?
     
  4. llavalle

    llavalle Member

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    Considering the following :
    85 pack is 16 modules of each 6 series of 74 cells. Total is 402V and 7104cells
    60 pack is 14 modules of each 6 series of 60 cells. Total is 352V and 5040cells (not sure about that one)

    Since they want to simplify their line, making the same modules for all cars would make sense.

    My guess? 14 modules of each 6 series of 74 cells (aka 14 of the 85kWh modules). Total would be 352V and 6216cells.

    Only flaw to my plan is that this ends up being a 74kWh pack :D.
     
  5. jjkroll

    jjkroll Member

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    I say there is something interesting going on. Notice that the 70D EPA rating doesn't appear to take much of a hit in wh/mile like the 85 does. From the 60s 209 mile EPA spec, 70D would be 209*70/60=244miles. The 85 would have been 296 miles, with no weight gain penalty. So, for the 85, the weight gain penalty was 31 miles. For the 85D the penalty was only 26 miles. So somehow they got the 70D for only a 4 mile penalty over the 60 efficiency.

    This makes it clear as mud, that Johan is right.
     
  6. Johan

    Johan Took a TSLA bear test. Came back negative.

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    Sorry, was posting from mobile (Tapatalk) so the poll doesn't show up.
     
  7. sorka

    sorka Active Member

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    Assuming the same anti brick buffer and below 0 mile buffer of 8.8 kwh, this would put the 70 in the 255 wh / mile range. Is that possible?
     
  8. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    I like your thinking. How about 13 of the 85 style modules. That would be 13/16 * 85kWh = 69 kWh. That is pretty close enough in Tesla specs to call it a 70... :wink:
     
  9. glhs272

    glhs272 Unnamed plug faced villian

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    Unfortunately that would lower the voltage of the pack, so I don't think so..

    Nope, we are finally seeing some new cells! 100kwh packs here we come.
     
  10. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    It's only a slight lowering of the Voltage, and if you are not looking for max performance, a fully charged DC Voltage of 325 Volts (13/16*400) is probably fine for normal driving.

    Of course, new cells could be happening. If we assume these are new cells in a 60 configuration, that would be 70/60*85 or 99 kW for an 85 configuration. That is pretty close to 100, would love to see it!
     
  11. Clprenz

    Clprenz Member

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    My guess is new cells. In typical tesla fashion they will announce the 100kwh pack after they have real world data on these new cells.
    The price increase can come from: Supercharging: $2,000 Navigation included: $1,250 less (from what I remember). AWD $5000
    Meaning they included $8,250 worth of product for a $5000 price increase. Pretty cool of them :)
     
  12. glhs272

    glhs272 Unnamed plug faced villian

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    Seems like right now most people think this is just a repackaging of the same old cell. I think the clues we are given suggests otherwise. If they are just adding cells to the original 60 pack, then we should see a heavier car with a corresponding drop in efficiency. But from the new specs on the 70D, it looks like it is retaining near identical efficiency of the S60. This suggests the battery didn't get much heavier.
     
  13. AmpedRealtor

    AmpedRealtor Active Member

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    This portends potentially larger packs for the Model X.
     
  14. glhs272

    glhs272 Unnamed plug faced villian

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    Exactly :)
     
  15. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    I like the ring of the X99, but the X100 is probably better for sales! (70/60*85=99)
     
  16. jerry33

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

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    Well, I'd like to think larger capacity (because that would mean a 95 or better pack in a few months), but what I think they did was put in an 85 pack and software limit it to 70. That way there's only one battery to make.
     
  17. Twiglett

    Twiglett Single pedal driver

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    That would be interesting - did they ever offer the option to 40 owners to unlock the 60 packs?
     
  18. Stoneymonster

    Stoneymonster Active Member

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    Yup.
     
  19. GSP

    GSP Member

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    Yes. Tesla offers software upgrades to 60 kWh for all of the 40 kWh models built.

    GSP
     
  20. benfrank3

    benfrank3 Member

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    Why not just use the 85 battery pack and software limit it to 70 kwh? That's what I think they did.
     

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