TMC is an independent, primarily volunteer organization that relies on ad revenue to cover its operating costs. Please consider whitelisting TMC on your ad blocker and becoming a Supporting Member. For more info: Support TMC

Displayed range takes no account of battery degradation.

Discussion in 'Model S: Battery & Charging' started by Peter Lucas, Mar 29, 2018.

  1. Peter Lucas

    Peter Lucas Member

    Joined:
    Apr 6, 2016
    Messages:
    240
    Location:
    San Diego
    My car (2016 90D, Model S) has a slightly degraded battery (72-73 available kwh) and it still displays a 275 mile range when fully charged. My actual range, driving at 340 wh/mi, is about 200 to 220 miles.
    The cars display of range takes no account of battery degradation.

    This was a dealer demo car with 7,500 miles on it when purchased. I was fairly certain that my actual range was less than advertised from day one. Miles driven and remaining range did not correlate. Even after correcting for a slightly higher wh/mile. Also kwh used compared to percent of battery used repeatedly revealed a 72-73 kwh available battery capacity. But these were for a portion of battery use of around 50%, so they were suspect. I finally got a Tesla rep on the phone who instructed me to take 3 trips that brought the battery from 100% to around 10% and make note of range, wh/mile, and kwh used. Taking a trip which terminates at 10% SOC is a bit tricky to plan. But I did it. Once so far. I plotted this on a few spreadsheet graphs and found that the miles driven, energy used, and SOC display all correlated very well throughout the trip. It was all quite linear and well calibrated. This validated my earlier measurements of decreased battery capacity. And confirmed those measurements of battery capacity of 72-73 kwh rather than the expected 85 kwh of available energy. Now I need to find the time to repeat the test two more times and see what Tesla has to say. Is a 15% degraded battery worth complaining about?
     
    • Disagree x 5
  2. David29

    David29 Supporting Member

    Joined:
    Aug 1, 2015
    Messages:
    2,045
    Location:
    DEDHAM, MA
    Leaving aside anything else, your energy use of 340 Wh/mi seems very high as the basis for range calculations.
    On my 70D, the "benchmark" energy use is 292 Wh/mi. That is the rate that corresponds to the EPA rating for the battery, and is therefore what I understand that Tesla uses to calculate range when you set the battery display for distance rather than percentage. It is achievable in nice weather -- spring or fall with little or no AC or heating needed -- at moderate highway speeds. The 90D is a bit heavier and has more powerful motors, so the benchmark energy consumption would be more, but I should think your EPA rated energy use would be quite a bit lower than 340.
    On the other hand, the benchmark rate I used is based upon having a 70 kWh battery, and as you point out, it is well known that the effective battery capacity is less that the advertised capacity.
     
  3. jaguar36

    jaguar36 Active Member

    Joined:
    Apr 10, 2014
    Messages:
    1,961
    Location:
    NJ
    Sure it does, when it was new the 90D had a range of 294 miles. I don't recall exactly what rated wh/mi is for the 90D but I think its around 285wh/mi. If you're running 340wh/mi that's about 20% worse, which is why you're getting 20% less miles.

    After you've owned the car for awhile you'll see the range at 100% drop a mile from time to time.
     
    • Disagree x 1
  4. TexasEV

    TexasEV Well-Known Member

    Joined:
    Jun 5, 2013
    Messages:
    7,632
    Location:
    Austin, TX
    OP, you’re just wrong. Your energy consumption is greater than what is used to calculate EPA rated range. The displayed range is how far the car will go on the EPA test cycle. It decreases over time with battery degradation. That’s how battery degradation is assessed.
     
    • Like x 2
    • Disagree x 1
  5. Peter Lucas

    Peter Lucas Member

    Joined:
    Apr 6, 2016
    Messages:
    240
    Location:
    San Diego
    340 was a typo that I couldn't go back and edit. On my trial trip, my consumption was unusually low, around 310 or so. I would have to look it up. It was less than the rated 324 that the rep told me about. My long term consumption rate is about 345. And my range is low even after factoring that in.
     
    • Informative x 1
  6. Peter Lucas

    Peter Lucas Member

    Joined:
    Apr 6, 2016
    Messages:
    240
    Location:
    San Diego
    The displayed range is about what it should be for a new, normal battery. ( My actual range, after factoring in a different wh/mile is about 15% less. The displayed range is not accounting for a degraded battery.
    The rated consumption rate for the 90D, model S, is 324 wh/mile, according to a Tesla rep who explained all of this to me on the phone.
    Fluctuations of maximum range do not necessarily indicate that battery degradation is being properly accounted for. From example, small changes in fully charged voltage would be expected to change the calculation of range.
     
    • Disagree x 1
  7. Peter Lucas

    Peter Lucas Member

    Joined:
    Apr 6, 2016
    Messages:
    240
    Location:
    San Diego
    Nothing wrong with my calculations, observations and conclusions. They are the only conclusions which fit the facts. Except one typo in the first paragraph. On my test run my consumption was 320 not 340.
    Fact 1) Tesla's rated consumption for purposes of calculating rated range is 324 wh/mile. This from a Tesla rep.
    Fact 2) From day one, my car has had an actual range of about 220 miles, after factoring my actual wh/mile to 324.
    Fact 3) The displayed full charge range on my car is around 270 miles. (This correlates to a consumption of 324 wh/mi and a useable capacity of 85 to 90 kwh.)

    The only conclusions which fit the facts are: 1) My battery has a useable capacity of 72-73 kwh, and 2) The display of range is calculated based on a battery with a useable capacity of 85-90 kwh.
    Thus, the cars display of range takes no account of battery degradation.
     
    • Disagree x 2
  8. ucmndd

    ucmndd Well-Known Member

    Joined:
    Mar 10, 2016
    Messages:
    5,190
    Location:
    California
    No it’s not. Simple math should tell you that. Even if the “90 kWh” battery actually had 90 usable kilowatts, that would turn into an EPA rated range of 278 miles for a 90D (90000 / 324), not the 296 advertised.

    I advise you to be extremely skeptical of anything a “Tesla rep” tells you on the phone.
     
    • Informative x 1
    • Like x 1
    • Disagree x 1
  9. sorka

    sorka Well-Known Member

    Joined:
    Feb 28, 2015
    Messages:
    6,922
    Location:
    Merced, CA
    A new first first gen 90 battery 90D will display 297 miles fully charged before any degradation.

    The OPs stated full charge is nearly spot on with how much available kWH are left so the OPs assertion is false.
     
    • Like x 1
    • Disagree x 1
  10. chillaban

    chillaban Active Member

    Joined:
    May 5, 2016
    Messages:
    3,723
    Location:
    Bay Area
    Yeah, sorry, the OP's assertion is not correct. I've experienced mild range degradation on both of my Teslas and it shows up as reduced rated miles at 100% charge. Consumption differences can very well be placebo effects or external factors, but the car definitely does not represent degradation as ballooned consumption rates.
     
  11. TexasEV

    TexasEV Well-Known Member

    Joined:
    Jun 5, 2013
    Messages:
    7,632
    Location:
    Austin, TX
    Your fact #1 is incorrect. The figure the “Tesla rep” quoted you is for the Model X, not Model S. You’ll soon learn not to believe everything Tesla reps say. (Search “stupid things Tesla reps have said”). You’ll also soon learn to believe most people who have been around here a lot longer than you have.

    Model S dual motor non- performance versions are about 285 wh/mi for rated range. Look where the dashed line is in your energy graph.
     
    • Like x 4
    • Informative x 1
  12. GatorGuy

    GatorGuy Member

    Joined:
    Feb 25, 2018
    Messages:
    529
    Location:
    Jacksonville
    285 sounds a lot more realistic.
     
  13. Peter Lucas

    Peter Lucas Member

    Joined:
    Apr 6, 2016
    Messages:
    240
    Location:
    San Diego
    Sorry, Texas EV. Rated range for a new 90D Model S, is often found to be less than 285 miles:
    This list took me about 20 seconds. I'm sure there are more.
    "My P90DL showed 265 miles at 100% in September when I got it."
    "My P90D charges up to 266"
    "100 percent charge I only show 271 miles"
    So unless they all have degraded batteries as well as mine, the rated wh/mi used for the calculations is probably pretty close to the 320 that was quoted to me. Perhaps the rated wh/mi used to calculate range was changed from some time ago when you got your information.

    But that argument misses the point. The cars energy consumption display repeatedly shows an extrapolated useable battery capacity of about 72kwh. And the rated 100% range display is at or near that displayed on a new 90D. And that range is not achievable by any definition of ordinary driving.
     
    • Disagree x 3
  14. GatorGuy

    GatorGuy Member

    Joined:
    Feb 25, 2018
    Messages:
    529
    Location:
    Jacksonville
    Why did you quote P90D range when discussing 90D? Performance cars have a lower range than their non performance counter-parts. For example my P100D has a rated range of 315 vs the 100D of 335.

    BTW, the 285 he mentioned is not the range, but the energy usage.
     
    • Informative x 2
    • Like x 1
  15. jaguar36

    jaguar36 Active Member

    Joined:
    Apr 10, 2014
    Messages:
    1,961
    Location:
    NJ
    First off the rated range energy usage is not "often found to be" it is a fixed value defined in the firmware of the car.
    Second off, the P models have lower rated range (and higher energy consumption than the regular models. Rated 100% range on the S P90D was 270 miles when new, perhaps that is what your confusion is. It's also possible you looked at some old screen shots where the 90D's range was listed as 270 with a little asterisks, saying that was based on the 85 pack and the 90 should be 6% better. (see here) Once the EPA testing was complete it was updated to this, showing the 294 mile range. (see here)

    Here's a video of a few month old 90D showing a rated range of 289 miles

    Lastly, as myself and almost everyone else here has noticed your rated range will slowly decline over the years. For instance on my 85, it originally displayed 265 when it was new and now displays 258. If you look at some of the battery degradation surveys they are always based on the displayed range, and you can clearly see the degradation curve.
     
    • Informative x 1
  16. roblab

    roblab Active Member

    Joined:
    Jul 15, 2008
    Messages:
    3,294
    Location:
    Angwin (Napa Valley) CA
    So you've found out what the range of your car is when you drive the way you do. Good. Now remember that number and mentally replace it with the number on the dash. Problem solved. I found out years and years ago that the guestimator on the dash knew less than I do. I hope you find this out too.
     
    • Like x 1
  17. fasteddie7

    fasteddie7 Member

    Joined:
    Aug 12, 2016
    Messages:
    857
    Location:
    uniontown PA
    Just change to percent and never think miles or kilometers again!
     
    • Like x 2
    • Helpful x 1
  18. TexasEV

    TexasEV Well-Known Member

    Joined:
    Jun 5, 2013
    Messages:
    7,632
    Location:
    Austin, TX
    #18 TexasEV, Mar 29, 2018
    Last edited: Mar 29, 2018
    That’s not what I said. I said the rated range is obtained when driving at an energy consumption of 285 Wh/mi (rather than the 324 Wh/mi you quoted). So if you use more than 285 Wh/mi of energy, you will get less than the rated range. If you drive slowly with the wind behind you and have energy consumption of less than 285 Wh/mi, you will be able to drive farther than the rated range.

    And yes, the rated range of a new Model S 90D was greater than 285 miles. You were citing posts about the P90D. The performance versions always have less range.

    Do you really not understand the difference between rated range (miles) and energy consumption (Wh/mi), and between non-performance and performance versions, or are you just trying to confuse everyone?
     
    • Informative x 1
    • Like x 1
  19. AWDtsla

    AWDtsla Active Member

    Joined:
    Mar 3, 2013
    Messages:
    4,251
    Location:
    NE
    Your problem is that the real consumption is higher than displayed. Based on observations of my car, your real consumption is more likely closer to 390Wh/mi.
     
  20. sorka

    sorka Well-Known Member

    Joined:
    Feb 28, 2015
    Messages:
    6,922
    Location:
    Merced, CA
    FYI, the one disagree on my 100% accurate post was made by the OP but I'm sure everyone already figured that out.
     

Share This Page

  • About Us

    Formed in 2006, Tesla Motors Club (TMC) was the first independent online Tesla community. Today it remains the largest and most dynamic community of Tesla enthusiasts. Learn more.
  • Do you value your experience at TMC? Consider becoming a Supporting Member of Tesla Motors Club. As a thank you for your contribution, you'll get nearly no ads in the Community and Groups sections. Additional perks are available depending on the level of contribution. Please visit the Account Upgrades page for more details.


    SUPPORT TMC