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Kevin Sharpe's decreased Roadster range

Discussion in 'Roadster 2008-2012' started by Kevin Sharpe, Sep 7, 2014.

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  1. StephenM

    StephenM Active Member

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    Kevin, I understand that you feel that you got a below average battery pack so far as diminished capacity over time, but is there no limit to the damage that you're willing to inflict to Tesla to get your way or prove your point? With the amount of resources at your disposal, I would think that your time and energy could really be focused to better things and it quite frankly looks to be bordering on vendetta or that there are some other ulterior motives.
     
  2. rolosrevenge

    rolosrevenge Dr. EVS

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    Since your case wasn't proven, you shouldn't have undertaken this smear campaign. Also, do you intend to put as much effort into publicly apologizing should the data prove you wrong?
     
  3. brianman

    brianman Burrito Founder

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    "154m" 154 meters?
     
  4. TOBASH

    TOBASH Supporting Member

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    I don't understand... Is this image with car in "RANGE" mode or with car in "STANDARD" mode???
     
  5. dhrivnak

    dhrivnak Active Member

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    #485 dhrivnak, Sep 25, 2014
    Last edited: Sep 28, 2014
    I too have had a disconcerting drop in range this summer after a trip where I range charged 4 times. Covering 415 miles with few if any chargers did not give me many options. Below is my graph of ideal range in STD mode. Range_Graph.JPG

    And below is a zoom on just this summer. The drop happened just after my long drive. The breaks in the line are where I did some range charging. Range_Graph2.JPG

    The new battery pack can't get here soon enough.
     

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  6. tennis_trs

    tennis_trs 2010 2.0 Roadster Sport

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    What is the "disconcerting drop in range" you refer to here?
    The linear fit seems to show a gradual reduction in range. I would think that nearly any place you zoomed in on (in time), you would see similar multiple mile drops and increases.
    On the plots, everything would look a lot less disconcerting if the Ideal Miles axis was zoomed out to show zero to 195 (or 185).

    It looks like your car is probably about average or better relative to the PIA survey (I'm guessing since I don't know your miles, but expect at least average, especially since you apparently do some relatively long trips). Are you really already to the point where you would consider buying a new, higher capacity pack?
     
  7. wiztecy

    wiztecy Active Member

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    I think a plot of CAC with ideal miles would show a more accurate representation for dhrivnak's pack regards to range mode charges. I have a very high CAC, 156.11 (today's reading), but my std. mode ideal miles come to 184 when fully charged (and fully balanced). I've seen lower CAC yield higher ideal miles on other Roadsters/packs. Don't know the algorithm of this calculation and would love to know more. However if I had a choice, I'd choose to have a CAC that's higher than a higher ideal miles figure.
     
  8. djp

    djp Model 3 Performance

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    Ideal Range = CAC * 3.7V * 99 * SOC LIM / 143Wh/km

    Where SOC LIM is the SOC of the lowest brick. Use 230 Wh/mi for miles and take 40km (25mi) off if you're not driving in Range mode.
     
  9. wiztecy

    wiztecy Active Member

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    Thanks.

    I'm getting an odd number that's not ideal range, is the SOC LIM the SOC figure from the "SOC LIM" off the VDS (diags) or the SOC LIM number you extracted from the ahr.log file?
     
  10. djp

    djp Model 3 Performance

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    Either, but the SOC in the ahr.log is 15% high.
     
  11. dhrivnak

    dhrivnak Active Member

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    Yes if you look at the first plot since the range mode charges virtually all the days are now below the trend line. The slope with all data shows a loss of -.0041 miles/day or a loss of 1.5 miles/year or 1.5 miles/8000 miles. The second graph shows a loss of -.0293 or 10 miles/year a 6 fold increase.

    I live in an area 100 miles from any city. So to drive to a city and back is 200 miles, a range charge. So I either put on less than 20 miles/day or over 200. It is rare I am in-between those numbers. To lose the use of my car to go to Asheville or Knoxville is significant to me.
     
  12. tomsax

    tomsax Member

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    Although ideal range and CAC correlate pretty strongly, there is a fair amount of variation. The charge below shows standard and range mode ideal miles for the Roadsters that report a CAC value in the Plug In America Roadster battery survey.

    4bxYc75.png

    Some of the variation is probably due to the difficulty in getting an accurate reading: you have to let the charge complete, then wait 10 minutes for the car to calculate an accurate ideal range, then read it soon before it can drop (especially important for a range mode charge).
     
  13. djp

    djp Model 3 Performance

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    Some of the variation also comes from differences in the SOC of the lowest brick, which is another factor besides CAC in the ideal range calculation.
     
  14. JRP3

    JRP3 Hyperactive Member

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    Anyone know where this is all at now? Is Kevin still losing range, did Tesla do something?
     
  15. bonnie

    bonnie I play a nice person on twitter.

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    Any reply I start to type is snarky. Soooooo, I'll leave it at 'dunno'.
     
  16. TOBASH

    TOBASH Supporting Member

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    Maybe I'm new here, but I gotta say I was sorry to see this thread re-activated.

    He brings what might be a valid issue, but maybe if Kevin was less In-your-face and less with an with an-axe-to-grind I might be more sympathetic?

    I identify with Bonnie's reply.

    T
     
  17. Mr X

    Mr X Future Martian

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    Sounds like exceptional degradation to me. We can't fully control the inclosed operative nature of batteries. They can change and do things a little different regardless of said outcomes and still be considered functional.
     
  18. dsm363

    dsm363 Roadster + Sig Model S

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    I think it's time to let this thread go until we have definitive information.
     
  19. wycolo

    wycolo Active Member

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    To paraphrase dhrivnak:

    "I live in an area 90 miles from any WalMart. So to drive to a WalMart and back is 180 miles, a range charge. So I either put on less than 20 miles/day or over 180. It is rare I am in-between those numbers. To lose the use of my car to go to a WalMart is significant to me."

    The Roadster is susceptible to change from several different directions. On its horizon now is the coming '400 mile' battery. Fighting this is the slow but steady deterioration of its existing battery. But we should also consider the possibility of geo-political changes like civilization moving toward us: last week while leaving a nearby town I noticed a 100 foot tall WalMart sign near the highway. That can't be right, I didn't see it on the way in and this town has been promised a WM for over 10 years! But there it was, a completed store doing its best to blend into the scenery. Now, instantly, my Roadster is much more useful to me since the 120 mile round trip for weekly shopping is now a routine event. Also there is no mountain range to cross to get there.
    --
     
  20. dpeilow

    dpeilow Moderator

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    Blast from the past, but Kevin's car is now with a new owner.

     
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