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Buying a replacement ESS

Discussion in 'Tesla Motors' started by vfx, Mar 13, 2007.

  1. vfx

    vfx Well-Known Member

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    Going into a Roadster purchase you pretty much know the cost of part-replacing the tires, brakes, lights etc., but what about the ESS?

    Tesla does seem to be coy about battery replacement costs. Do they replace the whole ESS and give you back a "deposit" on the case, or do they just replace the inside of yours? Do they check all cells and replace only the bad ones? How much will this run? What about the labor? How much is servicing per hour (or per job) at the service centers? Is it Saturn money or Ferrari money?

    Considering the ESS is a 1/3rd the weight and as much as a 1/4 the cost of the car (E$$?) and must be replaced at some point, it seems like price would be something they might share with someone investing in a Roadster.


    e
     
  2. tonybelding

    tonybelding Active Member

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    I don't have any special inside knowledge about this, but I'll recount what I've picked up on the subject. . .

    Tesla haven't officially told the cost of the batteries in a Tesla Roadster today, but it has been estimated around $20,000. They have stated they believe the prices will decline year-by-year, and that when the first ones are due for replacement in customers' cars (after five years), they estimate the price should be around $12,000.

    If the ESS fails earlier, it's under warranty. There's a full warranty for the first year, and it's pro-rated after that, out to the five year mark. Also, it's not necessary to replace the entire ESS if only part of it fails. The cells are organized into 11 modular "blades" which can be replaced individually.

    Tesla estimates that after 100,000 miles or 5 years the ESS's capacity will be reduced to 80%. They assume most people will want to replace it at that time. It's not required that you replace it, you can stretch it longer if you are willing to put up with somewhat reduced range and performance. It's worth noting that even the "worn out" ESS will give you about 200 miles range, or around twice that of a brand new GM EV1. Also, my understanding is that a lithium battery tends to degrade more slowly as it gets older. So after five years the battery is actually losing capacity quite slowly.

    The other thing, of course, is that the ESS will surely be improved by 2012-2013, so there's a strong incentive to shell out for replacing it. The replacement pack might take you a lot further and last a lot longer. Exactly how much further and longer is impossible to say, I don't have a crystal ball. Tesla believe lithium batteries can double in capacity over the next several years. I've heard from one person working at a battery company who honestly thinks they will have five times the capacity five years from now. I'm properly skeptical of that. That would make the Roadster a 1250-mile car! It seems implausible, but we'll just have to wait and see.
     
  3. WarpedOne

    WarpedOne Supreme Premier

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    >> ... somewhat reduced range and performance.

    I only remember reading about reduced range because of capacity (energy density) degradation.
    Does power density also reduce? Meaning after say 5 years you won't get 4secs to 60 any more but more like 5-6 secs?
     
  4. tonybelding

    tonybelding Active Member

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    I don't remember exactly when or where, but I think in one of the interviews Martin Eberhard mentioned this, and it sounded to me like he was saying the acceleration performance will also reduce somewhat as the ESS ages.
     
  5. vfx

    vfx Well-Known Member

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    >Tesla haven't officially told the cost of the batteries in a Tesla Roadster today, but it has been estimated around $20,000.

    So someone buying a Roadster today has a battery replacement of 1/5 the cost of the fully loaded car (even more if it's stock). I'm just not sure I would be comfortable with the vagaries in the word "estimate".

    Of course an ICE car would need a major tune-up or engine replacement after 100K or 150K miles (though my old Prelude was doing OK at 120K) so the idea of a car renewal fee at some point is reasonable and to some extent, unknown but they guys are making these things now. They should be able to give at least today’s price and promise a small percentage range around it.

    > They have stated they believe the prices will decline year-by-year, and that when the first ones are due for replacement in customers' cars (after five years), they estimate the > >price should be around $12,000.
    >The other thing, of course, is that the ESS will surely be improved by 2012-2013, so there's a strong incentive to shell out for replacing it. The replacement pack might take you a >lot further and last a lot longer.

    Right. So will it be lighter, smaller, battery that has the same specs that is less expensive (will this require a new car-handling $etup?) OR will it be the same-same size and weight and be more money for all the new cells/miles? What is the plan?

    I'm so excited about the car, the technology, the company and how everything they are doing will permanently influence automotive landscape forever. It's the unknown future expenditures that creates fear.

    These questions will have to be answered for the more public-friendly “White Star”. There will be many more buyers of that car who will demand back-end accountability. (Like service fees)
     
  6. malcolm

    malcolm Active Member

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    Panasonic say that they will be developing a 3.6 Ah Li-ion 18650 cell

    http://techon.nikkeibp.co.jp/english/NEWS_EN/20070110/126295/

    However, I'm not sure about the power density. Also this extra capacity may simply be due to the lower cut-off potential of 2V which would make it harder to design a power delivery system relying on a battery pack with a wider max to min voltage range. Not ideal for the Roadster, but could be ok for White Star.
     

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