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concerns about the 40kWh pack

Discussion in 'Model S: Battery & Charging' started by Rifleman, May 8, 2012.

  1. Rifleman

    Rifleman Now owns 2 Model S's!!!

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    I have always planned on buying a 40 KW Model S. On an average day, I drive about 70 miles, and about once a week I drive 100 miles. The 160 mile range of the 40 KW seemed like a perfect fit for me. There are a few cities about 100 miles away from my home, that have public chargers available, so my 40 KW would even allow me to visit them.

    Then I heard about range mode / normal mode charging. I figured that would not be a problem, as most days I would be fine in normal mode, and I would only need to charge in range mode for my trips to the neighboring cities. Thats what range mode is for, and it would be infrequent enough that it would have little negative effect on my battery.

    The lack of DC charging on the 40 KW is a negative, but as there are no DC chargers within a 300 miles of my house, and I doubt Tesla has any plans to deploy them in my region any time soon, this was not really a big deal to me.

    What really has me concerned is the Rav4 EV. It has a slightly bigger battery, is less aerodynamic, but probably weights only a little more. It is advertising a 100 mile real world range. Let's assume the Model S 40KW is not going to do much better, since it is internally very similar. If the Model S only has a 115 mile range, and I loose 20% of that when not in range mode, I have 92 miles to work with. Right off the bat, one day a week must be in range mode just to complete my daily drive. The rumor I am hearing is that the battery is warranteed to be within 80% or original range. At the end of my warantee, I would be at about 73 miles range in standard mode. To give myself a little bit of leeway for error, I would have to charge in range mode every single charge. The end result would be a battery that is useless shortly after the warantee runs up.

    Right now, with the info I have, it would seem like my best option is to lease a Model S, with the plan of getting a bluestar when my lease is up. I dont think that the 40 would be a good choice for me 100,000 miles down the road, and the price point on the 60 KW is out of reach for me (even the 40 is a major stretch) Hopefully Tesla has the leasing options figured out by the time my reservation number comes up.


    Am I the only 40KW buyer who is starting to get a little bit of range anxiety? I am starting to worry that the 40 KW is a product that is destined to fail, and is only being made to offer a car at the magical "under 50K" price point.
     
  2. doug

    doug Administrator / Head Moderator

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    It's 40 kWh, not 40KW. Will update the thread title.

    I'm sure you're not the only one with this concern. The 40 kWh battery pack cars won't be available at launch. Why don't you just wait for reviews on the other battery packs and scale appropriately.
     
  3. brianman

    brianman Burrito Founder

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    Assumptions. 1. Source? 2. Initial photos of the new Rav4 EV suggest otherwise. 3. In direct conflict with Tesla's stated estimates.
    Conclusions. Both questionable, IMO.

    It's good to do the due diligence, but I think you're a bit in the tinfoil hat part of guesstimation.
     
  4. Rifleman

    Rifleman Now owns 2 Model S's!!!

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    That's exactly what I am doing (and part of the reason I waited as long as I did to put down my deposit)

    If the early 40kWh buyers report range more in line with 160 than with 115, I will be buying instead of leasing. Either way I am going to be driving a model s when my number comes up, the real question is in 36 months will I be driving a model S or a bluestar
     
  5. Larry Chanin

    Larry Chanin Model S Perf Sig 1055

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    Hi Brian,

    Rifleman is definately not a tinfoil hat crazy person as you rudely suggest. His concerns that the EPA range numbers for the 40 kWh battery may be near 100 miles are well founded.

    http://www.teslamotorsclub.com/showthread.php/4259-The-New-RAV4-EV?p=135821&viewfull=1#post135821

    http://www.teslamotorsclub.com/showthread.php/4259-The-New-RAV4-EV?p=135944&viewfull=1#post135944

    Larry
     
  6. Rifleman

    Rifleman Now owns 2 Model S's!!!

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    I fully agree the conclusion that the Model S will only do a little bit better is questionable (I hope my concerns are completely unfounded on this one). Right now, the Rav4 is advertising a range that is about 40% less than the Model S, with what is essentially the same size battery. I am not an automotive engineer, and I cannot even begin to determine if the aerodynamic and weights differences between the two vehicles should reflect that large of a difference. But the second conclusion that is the model S only has a 115 mile range, and charging in standard mode results in 20 % (top 10% and bottom 10%) not being used, the 92 mile range figure is pretty solid (unless I am worse at math than I thought).

    has any word been given if the 100 mile range on the Rav4 is in range mode or standard mode? I suppose this would have a big impact of my guesstimates.
     
  7. ElSupreme

    ElSupreme Model S 03182

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    I probably have very similar driving habits to you. Daily driving on a LEAF would be too close to deal with every day. I think the 40kWh Model S will be perfect for everything but driving 240 miles to Charlotte, NC and ~300 miles to Florence, SC which I do about 2-3 times a year each.

    I am a little concerned about battery degradation over 5 years of driving ~20k miles a year. But I currently fill my car up with gasoline 90% of the time after my car says 0 miles to empty (it has about a gallon remaining). I think after about 18 months of driving an EV I will feel very comfortable running the car about 10 miles from empty. So as my comfort window narrows from battery degradation my comfort factor gets closer to the edge of the battery.

    I am a little concerned that my office/job will move or that I may move (to another city) in the lifespan of the car. But keeping a commute within 70 miles (which should be fine even after 100,000 miles of degradation) round trip shouldn't be that hard.

    I am fully planning on getting the 40kWh pack, and driving it until it dies.
     
  8. brianman

    brianman Burrito Founder

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    Always a student of the social experiment...

    What was rude in what I said?
     
  9. ElSupreme

    ElSupreme Model S 03182

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    I think generally suggesting someone wears a tinfoil hat, or is paranoid is generally frowned upon. I am paranoid so is really doesn't bother me, but for people who are paranoid about seeming paranoid it may be a problem. :smile:

    I have no problems with tinfoil hat, as I routinely wrap RFID cards/chips in tin foil, for the privacy benefits.
     
  10. brianman

    brianman Burrito Founder

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    I still don't see how that's rude, but understood.

    What I meant was that the guesstimations are a bit premature and paranoid, not the author. :)
     
  11. Rifleman

    Rifleman Now owns 2 Model S's!!!

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    No offense taken. I think with the information we have right now (the only 2 data points we have for vehicles with a battery of this size are the Rav4 and to a lesser extent the Coda) the estimates are as accurate as can be made. When more data becomes available, I will definatelly revise them. I think we are all hoping that the Tesla secret sauce results in a 40 kWh with 40% more range than the other 40kWh vehicles on the market, but without data, assuming anything else would be premature.
     
  12. crzyskl

    crzyskl P6398

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    I haven't owned alot of cars, but the ones I have owned, never perform as the EPA says they will. I put very little stock into the EPA testing and how it compares to actual people driving the car. My current Prius since ownership (55,000 miles) gets 58mpg (above EPA), but our 2011 Hyundai Tucson gets 24mpg including alot of open highway driving (below EPA). Correct me if I am wrong, but the indication I get from most Roadster owners on this forum is that the 245 miles range is pretty accurate (again, I could be wrong), sometimes a little more sometimes a little less.

    It does make sense for you to wait so you can double check to ease your range anxiety, but it sounds like your CURRENT concern is with how the EPA says its going to perform and hopefully your range anxiety will be eased when real drivers start driving the cars in real world conditions.

    Quick question for anyone who knows: Is the current RAV4 EV the same battery technology (chemistry, etc) that is going into the model S? That might also have a difference in the expected range. I am just a Quality engineer, not a real engineer.
     
  13. mnx

    mnx 2013 P85

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    Tesla has rated it at 160miles @ 55mph. Just keep your speed as close to 55 as possible on the highway and you'll have no problem. :)

     
  14. qwk

    qwk Model S P2681

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    We do not know what size of pack and what cells Rav uses. If the model S performs like the roadster(there is no indication why it wouldn't), then it will be very possible to get 160 miles in range mode.
     
  15. ckessel

    ckessel Active Member

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    The press release mentioned 41.8 kWh as I recall for the Rav4EV.
     
  16. Larry Chanin

    Larry Chanin Model S Perf Sig 1055

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    I don't know whether you had a chance to review the links I provided up thread, but here's the meat of my first link.

    An excerpt of Tesla's 10-K Annual Report:

    When you do the math,

    EPA 5-cycle range = .7 x 160 = 112 miles in range mode.

    I don't know the answer, but my guess is that Toyota did similar math as above, using range mode, it came out a little above 100 miles and they rounded down.

    Larry
     
  17. Robert.Boston

    Robert.Boston Model S VIN P01536

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    My summary of the thread: wait and see.

    We don't know how conservative Tesla is being stating the 100 mile range; we don't know the Model S range in actual driving conditions. By the end of the summer, I expect that we'll have many more data points about the second of these, which is what you really care about.

    My guess is that careful driving will take the 40kWh pack 160 miles. If you drive 75 mph along I-71, though, you'll do worse.
     
  18. spatterso911

    spatterso911 MSP#7577 **--** MX#1891

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    Then there is also the question of total range (full charge) and ideal range.
     
  19. Larry Chanin

    Larry Chanin Model S Perf Sig 1055

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    Hi Robert,

    Obviously, folks always can wait and see, but we can also make reasonable guesses as what the EPA range will be.

    We know that Tesla is advertising a 160 mile range driving at a constant 55 mph in range mode. We have found in the case of the Roadster the range at 55 mph was in close agreement with the EPA 2-cycle test. We know that EPA has a guideline in which they will mulitply the 2-cycle range by .7 to arrive at the new 5-cycle range. So if the Model S' advertised range at 55 mph is also close to the EPA 2-cycle range, then we may have a good approximation of what the new EPA range will be by multiplying the advertised range by .7. (Refer to the second link my earlier posting.)

    The new EPA 5-cycle test is supposed to offer a more realistic range in typical driving conditions and it was adopted to help consumers in arriving at reasonable expectations. Sure people can do better than the EPA range number if they drive slower or less aggressively. The question is will they? :wink:

    Larry
     
  20. ElSupreme

    ElSupreme Model S 03182

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    Slower and less aggressively than a F1 driver? Sure.
    Slower and less aggressively than 98% of the people on the road? Probably not! :biggrin:

    Then again I am banking on a range (range mode) of 112 miles. And a range (standard mode) of 89 miles. With my normal driving habits, (~70-30 highway/city). And when I expect to need to drive further I have been known to be able to drive 55mph.

    I personally think the EPA range will be about 130miles, which will correspond to cruising at about 65-70mph. Based on numerous rough number crunches looking at a variety of energy consumption graphs.

    My real hope is that the 40kWh Model S can cruise at 75mph over 100 miles on a mild summer day.
     

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