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60 KWH vs. 85 KWH, high mileage and warranty

Discussion in 'Model S: Battery & Charging' started by Subhuman, Aug 4, 2013.

  1. Subhuman

    Subhuman Member

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    Hey everybody, longtime lurker first time poster. As with most of you I have been obsessing for years over the Model S. I have never bought a car for anything close to what the Model S cost. I am somewhat able to justify purchasing the vehicle because I drive 110 miles around trip to work 5 days a week. I easily put 32,000 miles or more on a car in a year. Based on my driving habits I feel confident that a 60 KWH battery will work for my needs even factoring in future degradation and cold weather driving.

    The issue is that the warranty for a 60 KWH battery is only good up to 125,000 miles which might last me 4 years. the 85 kwh battery is unlimited. I plan on keeping the car 8-10 years which could result in mileage in excess of 300,000. Is the 60 KWH battery capably of this or is it just to many cycles for the batteries? If I buy the 85 kwh battery I am basically paying $7,000 (under the current configuration) for an extended warranty. I think I remember reading about a roadster that had over a 100,000 with minimal battery degradation but has any came close to 200,000 yet? I was hoping that some of you battery experts out there can let me know what i am getting myself into with that many miles. In addition, I was wondering what other high mileage drivers have chosen. any help would be much appreciated. Thanks!
     
  2. AmpedRealtor

    AmpedRealtor Active Member

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    I would opt for the 85 kWh battery if I were you. To get the maximum 208 EPA rated miles out of the battery would require a 100% charge every time. I believe this is called a "range charge" or something to that effect. Whenever you charge to this high level, Tesla pops up a warning to let you know that charging to this level on a regular basis can result in reduced battery life. Tesla recommends charging to 90% on a day-to-day basis, with only occasional 100% range charges. Taking that advice into account, your 208 mile rated battery becomes a 187 mile battery. You will want to give yourself a 20% padding just in case, so your realist range is closer to 150 miles. After a 110 mile roundtrip commute, you are left with only 40 miles. That 40 miles can disappear quickly if you are driving up hills, heating or cooling your vehicle, stuck in traffic, or a combination of these.
     
  3. Subhuman

    Subhuman Member

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    I just realized that I have 80 instead of 85 in the thread title. I cannot find where to edit the post. If a moderator could correct the title, I would greatly appreciate it. Thanks!

    - - - Updated - - -

    AmpedRealtor,

    Good point about the range charge vs. standard charge. While I did not read it anywhere I had assumed the 208 EPA milage was based on a standard charge not a range charge. Also some additional info, I do have access to a 110 outlet at work so I could charge an additional 30 miles or so at work. Also, a supercharger will be completed by the end of this summer in the city I work in. The terrain around here is pretty flat (Midwest) and I will definitely be needing to use AC and heat throughout the year.
     
  4. Bound466

    Bound466 Member

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    I drive 95 miles round trip 4 days a week, and about 145 miles 1 day a week. I got the 60, and I made the right choice. I've range charged about 10 times since getting the car in January. We've made effortless trips to Vegas from LA, and to San Fran. There have been a couple times we've had to drive the speed limit to save range.

    Like you, I plan to keep the car for a long time. No one really knows yet how much degradation we will have on the battery over 8 years. However, i have blind faith I guess that we will still be okay. If it does cause an issue, there might be upgrade opportunities. Also, I do not believe the longer warranty on the 85 covers normal degradation. The extra capacity may give you coverage though.

    Bottom line, as the months go by driving this fantastic machine, I'm solidly confident that getting the 60 was the right choice for me. I think you'll agree if you go down the same path.
     
  5. jerry33

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

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    1. Somewhere, Elon has said that the design for the battery was double the warranty.

    2. The Plug In America survey of Roadster owners indicated that the Roadster battery was getting 20% to 30% better than Tesla advertised.

    3. Prius ownership has taught me that the battery is only an issue to those who never had a car with a big battery. The only exception to this I am aware of is the Leaf in hot climates. (Yes, I realize the chemistries are different)

    Having said all that, with a 110 mile per day drive, I'd get the 85 kWh battery.
     
  6. garcilamd

    garcilamd Member

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    With battery swapping, it may also be worth it to use the 60 battery for a few years and then swap out to the larger capacity and keep it for the price difference. All depends on how much this will cost but at least upfront can reduce your expense by 10K
     
  7. montgom626

    montgom626 Active Member

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    get the 85 kW battery. No one ever complains that the battery is too big.
     
  8. AmpedRealtor

    AmpedRealtor Active Member

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    All EPA and ideal range numbers shown on Tesla's web site are for maximum "range" charge - they are not for a standard 90% charge. If you can plug-in at work or hit a supercharger, a 60 should be fine. However, the previous poster is correct in that I've never heard anyone complain about their battery being too big. So whatever you feel your issues may be before getting the car may feel 10 times worse after you get the car. You'll have to live with that 60 kWh battery for the life of the vehicle. There currently are no policies from Tesla promising any upgrade path for larger batteries. Some here are quoting rumors and hearsay, not actual Tesla policies or announcements.

    Buy into what you need and will likely use not just for daily commute, but also for the occasional detour, road trip, or unforeseen events. When spending this much money, think about how it would feel to have regrets in a year or two.
     
  9. dsm363

    dsm363 Roadster + Sig Model S

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    Agree. Get the 85kWh pack if that is possible especially since this will be a high mileage car.
     
  10. bluetinc

    bluetinc Member

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    A couple other (devil is in the) details.

    When the car shows 265 or 208 miles of range, that is the range when driving at the "rated range" (i.e. the EPA test) and is the mileage until the car stops driving (moving). Tesla takes some of that mileage and makes it hidden from the driver so when the car hits "0" you really have some number of miles left. This number will vary depending on the exacts of the battery size and current capacity, but as an example, an 85 that fully range charges to 265 miles will go about 249 miles till it hits 0, and have another 16 hidden (when driven as in the EPA tests).

    You should combine this info, along with a 70% number due to degradation, because of your long term mileage plan, to make sure the 60kwh pack will meet your needs. There is also significant benefit from only partially discharging Li-Ion batteries which means driving the same distance before recharging is "easier" on the larger battery pack. Unfortunately we don't have any real numbers to describe this for the Tesla battery packs.

    Personally, with your long term plan for the car lifetime and mileage of over 300k (without a battery replacement I assume), planing for really bad weather, unless your commute is under 100 miles, I would go with the 85.

    Minor note, if you have a 120V outlet at work, you should plan that during good weather you could get the 30 miles you mention (20A outlet?), but in cold weather you should plan for this number to be almost 0 due to pack heating needs in very cold weather.



    Peter





     
  11. yobigd20

    yobigd20 Well-Known Member

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    Get the 85kWh pack .
     
  12. dsm363

    dsm363 Roadster + Sig Model S

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    By 249 miles rated range are you not talking about 'standard' or now the 90% daily charge? You should get 265 rated miles of driving on a range charge.
     
  13. Gear

    Gear Member

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    I'd say you should probably get the 85kwh because of how many miles you're going to be driving per year so you get the better warranty. I think you'd be set for range with the 60kwh if it weren't for the fact that you're going to do 30k+ miles per year.
     
  14. bluetinc

    bluetinc Member

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    Sorta, when you drive, your rated range is decremented by a smaller energy unit (287 Wh/mi). This means that if you drive at rated range energy useage (306 Wh/mi on my car) you will arrive at 0 miles left after traveling about 249 miles. You can then continue to drive about 16 more miles before the car stops moving. In the end, that is the full 265 miles(249 + 16) the car is EPA rated for.

    Peter

     
  15. Subhuman

    Subhuman Member

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    This is something I did not consider. Two strikes in the winter....cold weather driving and minimal charging at work.:scared:

    Looks like everyone is saying what I really already knew deep down. In my own mind chopping 7 grand off of the sticker price makes the car appear to be more resonable but I agree 7 grand is a drop in the bucket compared to what I would already be spending. I so badly want this car but I keep telling myself that it is crazy to spend $80,000 plus on a car!
     
  16. bluetinc

    bluetinc Member

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    Ah, that I can help you with a bit! Just calculate how much you will spend on gasoline alone for 300K miles vs electricity (especially if you are getting to supercharge some of the time). I calculated that I spent over 40k just in gas on my old Honda...


    Peter


     
  17. dsm363

    dsm363 Roadster + Sig Model S

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    The car almost pays for itself=) If you pay for the installation, will work allow you to install an outlet or EVSE there?
     
  18. Subhuman

    Subhuman Member

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    #18 Subhuman, Aug 5, 2013
    Last edited: Aug 5, 2013
    Oh yeah, I have done the math and countless spreadsheets detailing TOC of ownership and this is the reason that i am even considering a model S. I would not by an $80,000 plus ICE because the TOC increase with the age of the vehicle instead of decreasing like the model S. I secretly root for gas prices to go up because with every increasing penny of gas price the Model S becomes cheaper.

    The GEN III really is the perfect price point for me but I can't wait another 3-4 years.
     

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