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Should I take my battery capacity concerns to the SC?

Discussion in 'Model S: Battery & Charging' started by demundus, Aug 28, 2015.

  1. demundus

    demundus Member

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    I have 62K miles on my 2013 that I bought used from a private party at 58k. I drive pretty conservatively, I like to play the battery game, and see how much energy I can save when driving.

    Now that I'm in a routine, charge -> work -> home -> charge, I've been noticing that my battery and trip figures seem kind of steep. I drive roughly 50 miles or so to and from work which is about ~20 kwh of energy. The drive to work is mostly uphill, so I spend about 330w/hr to get there, and finish at home with about 290 w/hr. Last night specifically, I drove a little more to a card game and the math just didn't check out:

    From trip "since charge" figures:
    Started day with 90% charge
    Ended day with 39% charge
    Drove 115 miles
    290 w/hr
    33.5 kw/hr

    Do those numbers seem off? Am I putting too much trust in the % battery meter?

    I've already been in for a drivetrain replacement, which had a very obvious clunk. The SC was fantastic and everyone was really cool about it. As I understand the "battery warranty", it only protects them from defects and workmanship, not degradation, so does this count? Do I become "that guy" who complains about his battery range to the SC?

    Thoughts?
     
  2. mknox

    mknox Well-Known Member

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    Those numbers seem pretty close to what I get. My commute is roughly 90 miles round trip, and I use a bit more on my way to work than I do going home. In nice weather where no a/c is needed, I might see between 265 and 290 Wh/mi at the end of my trip. I'll use about 40% of my battery's capacity in my 90 mile commute. WAY worse in the winter!
     
  3. Evbwcaer

    Evbwcaer Member

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    Those numbers seem a little bit off to me. You used 51% and went 115 miles at 290whm. That implies a range of about 230 miles at 290whm. At 290whm my S85 would get around 265 miles, has 17,500 miles on it and is 11 months old. I suggest you switch your display to miles rather than percentage and let us know how many miles are in your battery after a range charge.
     
  4. ecarfan

    ecarfan Well-Known Member

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    The 290 Wh/mi indicates you are driving moderately. Change your display from battery percentage to rated miles and live with that for a week. You should be achieving the displayed rated miles.
     
  5. mknox

    mknox Well-Known Member

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    As a data point, my March 2013 S85 with about 56,000 miles gets 218 Rated Miles @ 90% and 242 Rated Miles @ 100% ( was 240/265 on the nose when brand new).
     
  6. demundus

    demundus Member

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    I will go back to miles and report again... however I always used miles before, just recently did % to try to get the math right form a capacity perspective. Normal charge on miles is around 223.
     
  7. FlasherZ

    FlasherZ Sig Model S + Sig Model X + Model 3 Resv

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    Doesn't seem out of bounds for an early 2013 car with that usage (especially B-pack).
     
  8. Lex

    Lex Member

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    Hey mknox, like so how way worse, eg. 20 percent ??? I am mentally preparing for my first Toronto winter with the MS :redface:

    I got the 70D as it fit my current range needs, with around a 10 percent buffer, but it does make me anxious to think that more than a 10 percent loss could be realized within a few years...
     
  9. scottm

    scottm Active Member

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    I budget 25% less range for winter driving with the necessary heaters on.

    10% loss of battery capacity over few years does not seem too absurd. That number has been used this year in quarterly report notes.
     
  10. mknox

    mknox Well-Known Member

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    I have been tracking my energy use monthly (as well as "lifetime") since getting my car 2.5 years ago. My worst winter month is 55% higher than my best summer month over this period. My driving patterns are such that I do long daily drives (I have a 145 km round trip commute) and that will mitigate the difference somewhat since I find that once the car is over the initial really large energy hump, it will taper off to just a bit over summer levels as the car warms up and you're just cruising along. If you do a number of shorter trips in the winter, where the car and the battery keep getting cold soaked, your winter consumption will be a lot higher.

    On longer trips, I would count on using about 20-25% more energy than you would in the summer. On an average monthly basis, count on double your summer energy use. On the weekend, when I may just make short 1-5 km trips running errands throughout the day, I may see 5 to 10 times higher energy use than in the summer. This is because for pretty much the whole trip, the cabin and battery pack heater will be running full blast. You can offset this a bit by pre-heating your car for at least 1/2 hour while still on shore power before heading out.

    In this same 2.5 year period, I've seen a bit over 9% loss in battery capacity in about 90,000 km of driving. In comparing with other owners, I seem to be in the ballpark for degradation, although on the lower side of the curve. Because I ordered about a year before production began, there was no good information on how these batteries would hold up, and I did kind of plan for about this amount. I debated briefly with getting a 60 kWh model, but decided an 85 would be better since if it did degrade, I'd still have the range I need.
     
  11. Griffinlair

    Griffinlair Member

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    5 to 10 times more energy use?
    I hope that is not accurate. I haven't driven yet in winter, but going from 300Wh/mile avg to 3kWh/mile would not be good at all.
     
  12. dsm363

    dsm363 Roadster + Sig Model S

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    #12 dsm363, Aug 31, 2015
    Last edited: Aug 31, 2015
    I believe he is talking about short trips when the battery needs to warm up for the first few miles. You might see 900+ Wh/mile for the first few miles.
     
  13. mknox

    mknox Well-Known Member

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    I am. My energy use will go right off the scale of the graph. The trip display will show numbers north of 1,000 Wh/mi in those short trip scenarios.
     
  14. demundus

    demundus Member

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    Thanks for contributing mknox. I like hearing people who have nearly the same car in terms of miles and year.

    For everyone else, switching back to miles I'm seeing about 3% degredation.

    Start with 223
    End with 156
    59 mi traveled
    300 w/hr on the nose

    Thanks for keeping me sane everyone!
     
  15. Lex

    Lex Member

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    Yes thanks mknox and thanks demundus, 3 percent loss over 63k miles or almost exactly 100,000 km is excellent. If I recall the survey average was around 3 percent over first 80,000 kms then 1 percent for each 50,000 km after that. You seem to be past the quick degrade part and into the slow, consistent tail-off on the hockey stick. Your pack seems better than average.

    mknox has around 10 percent range loss in less than 100,000 km... I would be at the Service desk with my 70D at that point as it would be a problem for me. I'd say that anything worse than double the average of what others have so far experienced (eg. around 6 percent at 100k) would be concern worthy for me.

    I'm actually pretty ecstatic with the range of my 70D so far and I'm not fretting yet about range or degradation mostly because of what's coming. Our packs are easy to replace, are valuable even degraded, and new tech generally makes things better, cheaper, and lighter over time.
     
  16. mknox

    mknox Well-Known Member

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    When I look at other cars of similar age and mileage, I seem to be on the curve, albeit on the low side of it. I have asked my Tesla Service Center about it and they have checked and told me my battery is operating as designed with no defects. I definitely did see the big taper at around a year or so and it's been pretty flat since. As I've said, it was something I anticipated when I ordered (about a year before production) and other than numbers on the dash, it is not something that impacts me from a practical point of view. I have way more range than I need in a day, and have been able to do longer trips on the Supercharger network with relative ease. I am actually a lot less stressed about it since I changed my dash display from Rated to per-cent!
     

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