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For future revisions of the Model S, how big a battery?

Discussion in 'Future Cars' started by anticitizen13.7, Feb 9, 2013.

  1. anticitizen13.7

    anticitizen13.7 Enemy of the Status Quo

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    People trying to take winter road trips in a Model S have run into some difficulties with range and charging in the frigid Northeast:

    http://www.teslamotorsclub.com/showthread.php/13639-Worst-Case-Scenario

    http://www.teslamotorsclub.com/showthread.php/13633-NYT-article-Stalled-on-the-EV-Highway

    Driving slowly in the 50-55 MPH range, turning off the heat, and freezing in the car was not fun for these drivers. Now there were things that could have been done, esp. w' the NY Times reviewer, that could have mitigated or avoided these problems, but I take it as a given that drivers will inevitably make mistakes and unexpected things (like broken/incompatible charge stations) will occur.

    My question is, for future Model S, maybe a generation or so down the line, how big a battery is necessary if one wants to drive @ flow of traffic in cold temps without being frozen inside? Here are my parameters: Model S sized vehicle w' 19" wheels, 65-70 MPH cruise, interior cabin temp of 20C, headlights & electronics on, travel of about 250 highway miles.

    General rule of thumb I've seen is that 67% of EPA rating is reasonable for "worst-case" scenario, or approx. 177 miles for the 85 kWh Model S. To get to 250 miles, a 120 kWh battery therefore seems reasonable. Any thoughts?
     
  2. Mycroft

    Mycroft Life happens

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    A larger pack than 85kWh would require different battery tech to fit in the same space. So, IMO, it will not happen for at least 3 years and probably 5 years.

    The best we can hope for is Supercharging stations no more than 150 miles apart to allow freeway speeds regardless of temperature.
     
  3. FredTMC

    FredTMC Model S VIN #4925

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    yep. I agree with all points.
     
  4. widodh

    widodh Model S R231 EU

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    I'd like a 100kWh pack, since I think that's the sweetspot for me.

    We just need quick/fast/superchargers at more locations, maybe even 75 miles apart (I know, takes time!). So if something goes wrong, you can plug in earlier.
     
  5. Raffy.Roma

    Raffy.Roma Active Member

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    In Europe for the time being this is a dream. :)
     
  6. Kevin Harney

    Kevin Harney Active Member

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    and it makes way more economic sense for TM to put in more chargers than to expand the battery capability. Put them 150 miles apart to start and later come back and put one in the middle somewhere.
     
  7. constraint

    constraint Member

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    Ultimately it comes down to cost. I would love to see a MW/H pack but the weight and cost would be insane. As the density of power goes up and cost go down over time pack size will increase, but ultimately there will never be any size where someone wont want bigger. Fast charging (even faster the Telsa SC) has to be a major part of the solution to keep costs reasonable.
     
  8. VolkerP

    VolkerP EU Model S P-37

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    If you replace the 3100mAh cells in a 85kWh Model S pack with currently produced 4000mAh cells, you get ~110kWh pack. These cells just entered production (=they are too new, unproven durability & long time performance record) for Tesla to put them in a customer's car right now. But they use the same chemistry albeit have slightly increased cell weight.

    The 110kWh pack is only a few months of endurance testing away.

    I think Model S grew heavier and heavier during development, as engineering decisions had to be made on the safe side of crash worthiness, sound insulation, general robustness and performance. Weight optimization takes time. I think it's quite possible that Model S 2.0 easily sheds some 300lbs and decreases aero drag by a few percent. The 85kWh pack then would deliver true 300 EPA miles. There is still big incentive to increase efficiency along with battery capacity, since batteries will be the major cost contributor in any Model S/X or GenIII platform based car for the years to come.
     
  9. 100thMonkey

    100thMonkey Member

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    when I first got the Leaf, I salivated for the day the quick charging network was in place. Now, hmm, not such a fan of public charging, period. There are all kinds of limitations on the creation of a vast and numerable QC network. I think we need to set our sights on a 300+ range in the worst of scenarios: cold, rain/snow, head wind and elevation gain, say in the neighborhood of 150+ kW's. this is too expensive and heavy for now, but for the future, with a much more dense battery, more range will really be much more preferable than more fast charging, beyond a certain point. The side benefit of much more range will allow a more middle SOC charge/discharge more like PHEV's, and from what I can tell, PHEV's are much nicer to their battery packs due to the shallower charge/discharges. Quick charging is practically the only public charging worth having, but even then, it will never be able to serve as many cars as gas stations today, which of course will not be as necessary because the majority of charging will happen at home, but even still, once there are hundreds of thousands or even millions of EV's, those stations will need to be used very sparingly or long waits will ensue.

    IMHO, we need to go full tilt in the direction of bigger/denser batteries at the same time a good backbone of QC's are created and not try and rely too much on the idea that more fast chargers alone will fill the need. I think we are looking at at least 150 kW's maybe more in the future.
     
  10. aronth5

    aronth5 Long Time Follower

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  11. richkae

    richkae VIN587

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  12. aronth5

    aronth5 Long Time Follower

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  13. art

    art Member

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    do you think they will offer a 40 KWh battery again in the model s when the gen 111 comes out with its generation of battery.
     

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