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Aerodynamic Wheel + Active Air Suspension vs extra 70 mile battery pack

Discussion in 'Model S' started by stealthnhawk, Jan 12, 2012.

  1. stealthnhawk

    stealthnhawk Member

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    Hi all,
    I am trying to figure out which is the best way to gain extra mileage with limited funds.
    Assuming that my car is the based model = 160mile at 55mph.
    From reading from this forum, I've found the following (not sure how accurate).

    1) Normal, car is charged to around 85% of max capacity.
    2) If I drive 75% highway @ 75mph and 25% @ 30mph, I could lose extra 10% of the ideal battery.
    3) If i turn on ac/heat/etc, I could lose another 10%.
    The originally 160mi could be done to 100 to 110mi in real world driving.

    So now, I want gain more miles.
    1) Spend 10k and gain extra 70mi (ideal) --> 48mi (based on the above assumption)
    2) Spend 3k and buy the Aerodynamic Wheel + Active Air Suspension and improve by 8 to 16mi (from #2)? Does that make any sense?

    From the above, it seems that the Aerodynamic Wheel + Active Air Suspension are waste of money (unless you swim in cash of course). I should just save up and get the 230mi version since it has much better $/mi cost.

    Help please. thanks.
     
  2. Mycroft

    Mycroft Life happens

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    I agree with your assessment. You'll get much more bang for the buck by going for the larger pack.
     
  3. neroden

    neroden Happy Model S Owner

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    I don't see much functional point in the aero wheels unless you're already getting the largest pack and are trying to stretch out to maximum distances. (Which I kind of am. But you're not)

    Or perhaps the aeros might be worth it if you have some very specific use case in mind, going on a very particular highway for a very particular distance for which the extra range from them is all you need, but you'd have to have much more accurate range estimates.

    Personally, I also think the aero wheels will be prettier. :) YMMV.

    The air suspension's primary benefits are NOT range benefits. If you need greater ground clearance over bad roads, or want an extra-soft, extra-smooth ride, then it may be worth it. The range benefits on expressways are an extra. I happen to want better ground clearance on bad roads AND want an extra-soft, extra-smooth ride.

    So, agreed with Mycroft.
     
  4. stealthnhawk

    stealthnhawk Member

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    Thanks for both replies. So if you've mentioned that the air suspension is not for improving the mileage, I definitely should just focus to get the 230mi and forget about those 3k upgrades.
     
  5. stopcrazypp

    stopcrazypp Well-Known Member

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    Yep. The aero wheels improve range by a percentage point of the original range, so the larger packs will see a more significant improvement than the smaller packs. Not really as worthwhile to get it if you have a smaller pack.

    And I agree on the suspension too. It's primarily for convenience and comfort, I don't think it'll increase range that much (or Tesla would have estimated how much it would increase the range for the max pack, just like how they say the aero wheels will give an extra 20 miles).
     
  6. brianman

    brianman Burrito Founder

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    ... on the 300mi (85 kWh) version.

    AFAIK, they haven't quoted an estimate of the impact on the 160mi and 230mi versions.
     
  7. Robert.Boston

    Robert.Boston Model S VIN P01536

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    Also, the aero wheels and the air suspension will only have a material effect on highway driving, while the battery upgrade improves range under all driving conditions.
     
  8. WhiteKnight

    WhiteKnight _____ P85 #549 _____ Sig Red / Sig White

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    Driving 5 mph slower on the highway will get you more range than adding the Aero Wheels.

    Other reasons for jumping to 230 miles include:
    (1) Ability to SuperCharge with Tesla's proprietary DC network
    (2) Faster acceleration
    (3) Longer warranty
     
  9. NigelM

    NigelM Recovering Member

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    Get the larger pack and sleep better at night....
     
  10. gg_got_a_tesla

    gg_got_a_tesla Model S: VIN P65513, Model 3 Res Holder

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    Still don't understand the "Supercharging - Optional" and "Supercharger Access - TBD" part for the 60kWh pack at Model S Options and Pricing | Tesla Motors. Has this been dissected and deciphered elsewhere on this forum?

    Not that I truly care; I'm getting 60kWh anyway to indeed sleep better at night...
     
  11. brianman

    brianman Burrito Founder

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    My understanding is that we think this means that the car is compatible at 60 kWh but you might have to pay a fee to use the device.
     
  12. gg_got_a_tesla

    gg_got_a_tesla Model S: VIN P65513, Model 3 Res Holder

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    Thanks! Makes sense; even more so for me as I'd rarely, if ever, venture outside the greater SF Bay Area with my precious Model S - why implicitly pay for the Supercharger access (among other things), that I wouldn't ever use, as part of the $10K jump to the 85kWh whose additional range (and 0.3 sec 0-60 boost) I don't need.
     
  13. brianman

    brianman Burrito Founder

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    #13 brianman, Jan 13, 2012
    Last edited: Jan 13, 2012
    @gg
    And now for more opinion.

    IMO...

    There are technical reasons they are excluding the 40 kWh from supercharging. One of those technical reasons is battery degradation.

    The battery degradation impacts the 60 kWh as well, but in a less pronounced fashion. They want to discourage heavy use of supercharging for that reason, and also may want to recoup some of the costs of the infrastructure (hence the TBD while they figure it out).

    While the battery degradation theoretically impacts the 85 kwH, they don't expect it to be a significant issue. In fact, they don't expect -- for "normal" usage -- that they need to have it impact the unlimited miles warranty. Further, they are respecting the "top end" investment of 85 kWh buyers. They (potentially) aren't making them pay as much as the 60 kWh users as a perk, as well as implicitly suggesting that they don't think 85 kWh will need to supercharge as much anyway for typical drivers.


    In short, if you buy the 85 kWh then Tesla is doing everything they can to address range anxiety concerns -- since they aren't providing (on the S) an even longer range offering. If you step down to 60 kWh, they offer a range anxiety countermeasure (SC) but it is (potentially) more expensive to use. If you step down to 40 kWh, it becomes impractical to provide the countermeasure.
     
  14. AndrewBissell

    AndrewBissell Member

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    @brianman. Good analysis
     
  15. Doug_G

    Doug_G Lead Moderator

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    The larger pack is definitely a better bet, in terms of durability of the pack. Lower C rates means longer life. That's why the warranty gets better.
     
  16. Lloyd

    Lloyd Active Member

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    Access included means that Tesla pays for your charging!
    TBD means that Tesla is contemplating a fee for use.
     
  17. Mycroft

    Mycroft Life happens

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    Not necessarily Lloyd. It could be that the *capability* for supercharging is built in to the 85 packs but that there's a fee, TBD, to add that feature to the 60kWh packs. It could be that there are some gizmos or electronics that have to be installed in the car for supercharging to work.

    There still may be a cost to actually charge up the car at the station in either case.
     
  18. dmckinstry

    dmckinstry Model S - U.S. P - #1649

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    I'm sure that will eventually be the case, but the implications were that initially charging will be free. At least as far as I read it.
     
  19. Mycroft

    Mycroft Life happens

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    I appears that may be a distinct possibility. Pretty cool! I'm hoping that I can drive to Vegas and back with just the cost of wear on the tires and motel rooms. :)
     
  20. richkae

    richkae VIN587

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    Getting back to the original question:

    If the $1500 aero wheel option improved range by 6.6% it would have the same range/dollar effect as the 20kW battery ( improving range by 43%, from 160 to 230 )

    Suppose that the aero wheels improve range by 5% at 55mph.
    Further suppose that at 55mph exactly half of the energy expended is from pushing air out of the way and the other half is everything else ( tires, drivetrain ).
    That would mean that the aero wheels actually reduce aerodynamic drag by 10% to achieve the 5% range increase.

    If aero drag increases with the square of speed, then at 75mph it is 1.86 times the aero drag at 55mph - and it is up to 65% of energy expended to move at 75mph.
    Since the aero wheels reduce drag by 10% - that means a total energy reduction of 6.5% - thus at 75mph the aero wheels increase your range by 6.5%

    If that is all correct, then the aero wheels for $1500 are just as good in terms of only dollars/range at 75mph than the bigger battery.
    ( And the faster you go, the better the aero wheels get )
     

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