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Reading between the lines... 200 mile range with 35kWh battery?

Discussion in 'Model 3' started by commasign, Dec 27, 2014.

  1. commasign

    commasign Active Member

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    Tesla's announcement of the Roadster 3.0 retrofit claims a 400 mile range with a 70kWh battery pack using a new battery cell and some aerodynamic tweeks and low rolling resistance tires. Could this cell be the one used in the Model 3 for 200 mile range with a 35kWh battery pack?
     
  2. pr0teu5

    pr0teu5 Member

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    #2 pr0teu5, Dec 27, 2014
    Last edited: Dec 27, 2014
    Highly unlikely. First you must remember that the mass of the model 3 will be significantly higher than that of the roadster making it nigh on impossible to achieve the stated range with such a low capacity. All reasonable calculations come up with a value between 45~50 kWh for the model 3.

    It is also unlikely that the model 3 will use the same batteries as the 70 kWH pack of the roadster 3.0. The roadster 3.0 simply uses the panasonic 3.1mAH cells rather than the less capacious 2.1mAh cells of the older roadsters. Panasonic has several better cells available, and as increased density is one of the best ways that you can reduce costs, so you can bet that the gigafactory produced cells will be significantly better than the ones in the roadster 3.0.

    Hope that helps.
     
  3. wallet.dat

    wallet.dat Member

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    Please correct me if I'm wrong, but if you're going for range, cruising at a steady 65mph (or whatever speed), weight really isn't much of a factor. Granted, in more stop & go conditions, weight plays a big role, but when Tesla claims a 400 mile range, I don't believe that's in city type of traffic.
     
  4. SmartElectric

    SmartElectric Active Member

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    The Kia Soul EV has a 27kWh battery. That is about 70% of what you suggest, but it is only a 100 mile range car (in good weather). A 200 mile range car needs near 45kWh.
     
  5. djplong

    djplong Member

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    It doesn't matter what you get for range on the highway. What matters - or what WILL matter - will be the all-important EPA number that gets stuck in the window. That *has* to be over 200 miles. That's the number that everyone will quote. That's the only number that you can use to fairly compare any EV because the EPA runs them all on the same cycle.
     
  6. NigelM

    NigelM Recovering Member

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    The headline number is almost certainly going to be 200 miles but as the OP mentioned there are a number of factors that affect range (as we see with the Roadster 3.0 package); I also suspect that acceleration will be restricted to produce a 0-60mph in just under 6 seconds.
     
  7. ItsNotAboutTheMoney

    ItsNotAboutTheMoney Active Member

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    No. 400 miles with a controlled drive in a small, light 2 seater != 200 miles EPA in a cost-controlled 5-seater mid-size.

    They just want to do some PR while eliminating legacy tech.
     
  8. bluenation

    bluenation Member

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    ill be blown away if they achieve 200mi in less than 50kwh
     
  9. bxr140

    bxr140 Member

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    I dunno...if we're talking EPA range its seems achievable considering the s60 is 208 miles. Next Gen battery tech will be easier to package into a smaller/lighter car, LRR tires apparently are good for 3% or something and presumably tire tech is getting more efficient (?), aerodynamics are always improving (side view cameras, etc), and if all that rolls into a chassis with optimized gearing and consumption-smart electronics it would be surprising if the answer isn't easily under 50kwh.
     
  10. ScepticMatt

    ScepticMatt Member

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    Some napkin math...


    The S60 gets 208 miles on a 60 kWh battery
    The model 3 is ~20% smaller, so it has less drag area as well as chassis weight.
    The battery gets lighter as well, both due to technology improvements and less cells used.
    Throw in some extra drive train efficiency improvements
    So 25% more miles per kWh would be my guess.


    Result: 208 EPA miles, 48 kWh, 118 MPGe. (eGolf = 116)

    (1 gallon = 33.7 kWh, 81% battery and charging efficiency assumed by EPA)
     
  11. GSP

    GSP Member

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    The Model 3 cannot use the same cells. Tesla has announced they will use a slightly larger size. Industry experts expect Tesla to use 20700 cells, instead of the Roadster 18650 size. I would also expect the fuses to be external to the cell, like the Model S, not internal, like the Roadster.

    GSP
     
  12. commasign

    commasign Active Member

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    The not-so-aerodynamic Toyota RAV4 EV can be gently coaxed to over 150 miles with its 41.8kWh battery pack. Seems like a really aerodynamic Model 3 should be able to achieve 200 miles with a 50kWh battery.
     
  13. David99

    David99 Active Member

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    Yes that sounds reasonable. In the end it comes down to cost and priorities. What is more expensive to implement to achieve better mileage. A larger battery or a lighter material (that costs more to source and manufacture). I think the example of the BMW i3 shows that there are difference ways to do it. The carbon fiber material saves a lot of weight but costs a lot to produce. I doubt BMW makes a dime on the i3, but they are financing their carbon fiber manufacturing process to become mass production ready (at this point it is not). The Model E will most probably have only the front motor that is more efficient (as stated by JB).

    There is also a difference between USA and Europe or other high traffic city regions. The i3 for example was optimized for size and weight as it's designed as a city car where it's constantly acceleration and slow down. There is less higher speed driving, hence less importance on aero dynamics. The Model S is designed for the US market where it's more about cruising and longer distances, hence more focus on aero dynamics and larger battery, less on weight.

    It's going to be interesting where the focus/priorities will be on the Model E.
     
  14. the dude

    the dude Member

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    I think a 60KWh pack will be used on the model E

    did I hear Musk once say they wanted a solid 200 miles, at highway speeds, a 50KWh pack is not really enough

    the output of the gigafactory is 35GWH for 500K cars, if we knew how many of the 500K cars were model E, it would be easy enough to figure out the pack size
     
  15. ecarfan

    ecarfan Well-Known Member

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    No it's not an easy calculation because a large fraction of the Gigafactory production is planned to be stationary grid storage products according to Tesla.
     
  16. the dude

    the dude Member

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    the total output is 50GWh, 15GWh for grid storage the rest for cars
     
  17. green1

    green1 Active Member

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    What are the odds that model 3 will be 200 mile EPA? The Model S is a "300 mile" car, but it isn't 300 EPA...
     
  18. ScepticMatt

    ScepticMatt Member

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    Not unless they had a major battery breakthrough this year.
    Elon himself said since the car will have a "20% smaller pack"

    Elon Musk battery Model E 80 percent size - YouTube
    (from CPUC Thought Leaders Speaker Series - February 27)

    What Musk says is "200 mile usable range minimum".
    For a smaller car 50 kWh should easily be enough for 200 mile EPA.

    I'm pretty sure it will be, as seen above (and my earlier napkin math).

    The Model S was a "300 mile EPA" car before they changed to a new test cycle (2 to 5)
     
  19. the dude

    the dude Member

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    which costs more for Tesla, a bigger battery or lighter materials
     
  20. bluenation

    bluenation Member

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    unless you are grannying the thing, the S85 is closer to 200mi than 300mi in real world range

    i'd feel cautious about taking that 200mi figure for face value.
     

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