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Battery Degradation for a 60

Discussion in 'Model S: Battery & Charging' started by PEDZZZZ, Dec 4, 2015.

  1. PEDZZZZ

    PEDZZZZ Member

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    I apologize if this question has been answered previously. My Model S 60 now has a max range of 190 miles after 17 months and about 21,000 miles. This represents an almost 9% degradation from the rated range of 208 miles. I have typically charged to nearly the max of the "daily use" range, and have only done a handful (5-6) maximum "trip" charges in the lifetime of the car.

    Can anyone tell me if this amount of degradation is normal? From what I can tell from other posts, more typical degradation would be 4-5%.

    Thanks,
    Andy
     
  2. mknox

    mknox Well-Known Member

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    I have an S85, but my degradation, as a percent of new capacity, was almost exactly the same as yours at this point. The good news (at least for me) is that my car seemed to stabilize at this level and hasn't really lost any more in the last year to year and a half.
     
  3. gavine

    gavine Petrol Head turned EV Enthusiast

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    It's not actually degradation, at least not all of it. It's just the way the algorithm is reporting it based on assumptions. Try this:next time you charge to 100%, note how many miles you drive before the range starts to drop. Last time I fully charged, I was at around 190 and it stayed there for the first 10 miles or so and then started counting down.

    Report back and let us know.
     
  4. glhs272

    glhs272 Unnamed plug faced villian

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    My 60kwh car has 63K miles. Right now a range charge yields about 203 rate miles. That's about (203/209=.971) 2.87% degradation. My range calc is pretty accurate given that I charge to 90% daily, and range charge relatively frequently with 100% to near 0% drives.

    That said this seems to be unusually good.
     
  5. Doug_G

    Doug_G Lead Moderator

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    What really matters is the number of full charge cycles the pack goes through. The 60 will have a little less endurance than the 85, simply because it goes through more pack cycles per mile. Tom Saxton's survey data has shown that the number of pack cycles correlates very well with, and is the best predictor of, pack degradation.

    For example, if you average 250 Wh/km, and drive 100,000 km, that's 25 MWh. In terms of pack cycles, that's 294 for the 85 kWh, and 416 for the 60 kWh. The 85 will have only 71% as many pack cycles for the same mileage. So based on that it would last ~42% longer.

    This is ignoring any secondary effects, such as differences in efficiency due to differences in weight, aging, etc.
     
  6. FredTMC

    FredTMC Model S VIN #4925

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    that IS really good. I have 63k also on my 60kwh. I get 188 on a range charge and 170 to 90%.
    I hardly ever range charge. Maybe I should.

    - - - Updated - - -

    that seems like too much loss. Mine has less degradation.
     
  7. gavine

    gavine Petrol Head turned EV Enthusiast

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    It has been said that range charges to 100% balance the pack and help with the range algorithms so I'm not surprised that glhs272 is getting a high reading. That doesn't mean his/her pack has more actual range in it. It's just reporting more accurately.
     
  8. CSFTN

    CSFTN Member

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    This type of post comes up repeatedly. While certainly some do have battery degradation, it seems that for most this is about the algorithm, i.e. math not electricity. Going forward, when we in the community post these concerns, I'd like to suggest that we also post our average watts/mile. And I hope Tesla will give us (back, I think) the option of expressing our battery pack SOC as kWh instead of miles.
     
  9. glhs272

    glhs272 Unnamed plug faced villian

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    I think that there a bunch of factors:
    1) You are correct that my range charges and 100% to 0% drives keeps the algorithm accurate and battery balanced. Daily charging at 90% also helps the algo, but should theoretically degrade the cells faster.
    2) I think the low average temperatures of Wisconsin helps by keeping the pack cooler than say Florida. (when not driving anyway)
    3) I think I am "lucky" from the start. My car has been awesome in all metrics. From day one I could get 209/2011 rated miles (range mode off/Range mode on), which is good.
    4) I also charge as frequently as possible. My daily commute is drive to work (32miles), charge, then drive home (32 miles) then charge. Also relatives and friends have outdoor NEMA 14-50s *(installed by me), so I can charge at most places I go. Even if I don't "need" to charge, I do in order to keep the depth of charge as low as possible.

    I am thinking that the combination of the factors are what plays into the favorable range at my car's age and mileage.
     
  10. Morristhecat

    Morristhecat Member

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    I've got about 55,000km (34,000mi) over 2.75 yrs. My 60kw pack new charged 100% to 323km on about v4 software or so. The algorithm has changed over the years, but I assume it generally has the same goal to represent a prediction of the miles you can expect to attain. I rarely charge to 100%, but I often see my 90% charge drop to a level that would initially have alarmed me had I not been used to it. When I do charge to 100% it always seems to come back after a cycle or two. I recently charged it at 100% to 319km, which is pretty darn close to my original range. (1.2% loss - no big deal)

    I liken the whole charging process to quickly filling an ice cube tray with molasses from one side. The far side always is low, and thus the total reported back isn't as much as you would expect. However, if you go really really slow and things warm up a bit (ie: like charging to 100%) the far side of the tray will eventually fill up to where you expect it.
     
  11. FlasherZ

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

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    (Mods: can this be moved to the Model S battery/charging section?)
     
  12. gavine

    gavine Petrol Head turned EV Enthusiast

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    Shallow depth of charge is indeed good for the battery, however, in my opinion, charging so often might be bad for the onboard charger. I think there's a balance to achieve here. If you charge three times a day, you might wear-out the charger which might be worse than possibly losing a little bit of range from deeper charges. I have a rule that I try and keep the depth around 1/3 of capacity so on that's about 65 miles on my S60. If I only drive 30 miles on a given day and I have plenty of charge left, I'll skip a day unless I have a long trip ahead. I only charge to about 66% most of the time.

    So for me, I'd rather lose some range than have to replace the onboard charger down the road. Not that the chargers are unreliable (I haven't heard of many dying), but I just feel like that might be overkill to charge so often.
     
  13. qwk

    qwk Model S P2681

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    I really doubt that the charger would be affected, although the charge port might take extra abuse. The HVJB contactors will also get more wear, but they are rated for many hundreds of thousands on/off cycles, so the car would be toast before the parts will wear to the point of needing replacement. Those parts are also very cheap in relation to the battery.
     
  14. Rocky_H

    Rocky_H Member

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    Mods: Yeah, this really shouldn't be in the Model X subsection.
     
  15. Kipernicus

    Kipernicus Model S Res#P1440

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    40k miles for me, 175 at 90% and 196-ish at 100%
     
  16. bxr140

    bxr140 Member

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    I'm at 178 for a full charge (14%, if you're doing the math). 23 months, 40k miles, and 277 lifetime wh/mi.

    Service recently said 'no codes, battery is good, it's the algorithm, do 100% charges and deep discharges'. It's not a huge deal for me since I can still get to where I need to go (the longer supercharging events are a bit annoying...). I was a bit bummed the service guys didn't seem to think 14% was a huge deal. I think next time I'll ask if they can reset something.
     
  17. glhs272

    glhs272 Unnamed plug faced villian

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    Have you tried following their advice?
     
  18. DieAbetic

    DieAbetic Member

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    Another data point:

    I have a (just over) 1 year old S60. 26K+ miles. B battery pack.

    Last 100% charge a few weeks ago got up to 198 miles, but I drove for a good 3-4 miles before any drop. I 100% charge maybe once every month or two, but daily charge to 80-90%. Also roughly 10K of the total miles are on superchargers (not sure if that really matters).

    Cheers fellow 60s!
     
  19. Btrflyl8e

    Btrflyl8e Active Member

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    I have 45k miles in 2.75 years. I charge to 90% daily. I range charge when needed, not too often but generally a few times a quarter. When I had changed my pattern and was only charging to 70%, my algo got out of whack and my 100% was down to 182 miles, range mode on. I switched back to 90% daily, now I'm back to 198 miles at 100%.
     
  20. bxr140

    bxr140 Member

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    Well...to be honest, it's not an easy thing to do. I've 100% charged twice since I took my car in (I only got it back last Monday) so there's probably not enough data points for something to happen.
     

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