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Displayed range takes no account of battery degradation.

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

  1. sorka

    sorka Well-Known Member

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    The P90D has a different rated range than the 90D.
     
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  2. sorka

    sorka Well-Known Member

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    Dude! You have are 100% wrong and everyone has pointed out the same reason. You are conflating your actual range because of driving habits with displayed rated range. You're getting 15% less than your displayed rated has NOTHING to do with the cars calculated rated range.

    The tesla can and does easily get rated range provided you don't drive too fast, it isn't too cold, and your alignment is good.

    My P85DL averaged 286 wh / mile on my 130 mile commute home last night which is less than the 300 wh / mile it is rated for. I easily beat rated range and I was driving 70 to 75 the entire way and drove over two mountain ranges.

    [​IMG]

    Also, going around and marking factual posts that aren't opinionated because someone marked disagree on your 100% factually incorrect post is extremely bad form and will not win you any friends here.

    Consider trying to build up some social capital first before you start using that button.
     
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  3. GatorGuy

    GatorGuy Member

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    I gave you a like for simply averaging 286Wh/mi in a P85D. ;)
     
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  4. Peter Lucas

    Peter Lucas Member

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    The displayed maximum rated range and even the advertised range of a new 2016 pre-refresh Model S 90 D appear to vary between about 270 miles and about 285 miles. Mine, when new, and now displays about 275. So my cars display of maximum range implies that the battery capacity used in the calculation is that of a new, non-degraded capacity. Our cars also have a display of energy consumed since last charge, and on the current trip. Using those numbers, the calculations show that my car has a useable battery capacity of about 72 kwh.
    So my cars display of maximum rated range should be about 15% less than that of a new, undegraded battery. Since my car actually displays the range expected from a new, good battery, the conclusion is that my cars display of maximum rated range fails to account for the actual degraded capacity of my battery.

     
  5. TexasEV

    TexasEV Well-Known Member

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    OMG. Multiplle experienced Tesla owners have tried to explain why you’re wrong, but you keep posting the same incorrect stuff. I give up. Believe what you want to, but the EPA rated range of a new Model S 90D was 294 miles.
     
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  6. Peter Lucas

    Peter Lucas Member

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    I am happy for you that your car performs and displays ranges as it should. Mine doesn't. And since mine doesn"t, others may fail in the same way. I have explained in detail exactly how and why. I regret that a typo or misremembered value cannot be corrected in my original post. On that 90% test trip, my instruments showed a consumption rate of 306 wh/mi. Not 340 or 320.
    Two simple facts remain: My "90 kwh" battery has a useable capacity of about 72kwh. Yet my car displays a maximum rated range that is associated with a new, normal "90 kwh" battery. Probably 85 kwh. This should be of interest to anyone who thinks that their cars display of maximum rated range as an indication of battery health. It may not.


     
  7. Peter Lucas

    Peter Lucas Member

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    Sorry TexasEV. Look it up. You will find new car maximum rated ranges for new Model S 90 D's ranging from about 270 to 285 miles. Real life observations. I think that 295 number that you have was the advertised value for the 90 D'D's late 2016 on. After the fascia refresh.
    Yes. I see that many people are reluctant to believe that a Tesla could get this display of range so wrong in such an important way. But the numbers are there.
    The implication is that your cars display of fully charged range is NOT a reliable indicator of battery degradation.

     
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  8. Peter Lucas

    Peter Lucas Member

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    Pretty amazing that you can get 285 wh/mi from that car. I can only do that on my 90D with the wind at my back or downhill, or with no HVAC. But I did get 306 on my test trip on a day when the HVAC load was very low, and traffic density kept my speed down most of the way. Maybe, as you suggest, I have an alignment problem. But I think that they redid the alignment when they put in the new forelinks.
    What is your long term wh/mi?

    My calculations and assumptions are 100% correct. And their correctness does not rely on "social capital". Though the absence of it probably accounts for the hostility from those faced with facts that don't conform to long held beliefs. And there was no "conflation" of anything. But congrats on finding a way to use that cool word.
    I am simply reporting one fact: For one car, the displayed full charge range is not accounting for a degraded battery.
    Here is why I think that this is important.
    Before buying my Tesla, I was very concerned about battery degradation. I read everything that I could find. Including Steinbuch's extensive data. I took it at face value when so many people reported that their full charge range degraded very little even after several years of ownership. It never occurred to me that the cars display of range may simply fail to account for actual battery capacity.
    After a very short period of ownership, I noticed that my range was not nearly what was advertised. Everyone quickly pointed to driving style and excessive wh/mi. I understood that. That's obvious. So how to factor that out? I noticed that the car has a display of kwh used since last charge. Using that number with the SOC display, one can easily calculate the full charge capacity of your battery. I was then reminded, and I understood, that the only convincing way to use that information was to do a long distance trip which consumed most of a full charge. So I finally found an opportunity to drive the car from 100% charged to 10% charged. (That is not easy to do without risking getting stranded on empty.) The results of this test trip correlated with all of my other shorter trips. And incidentally showed really good linearity of the SOC display against both energy consumed and miles driven. Kudos to Tesla on that. SOC is apparently not easy to get just right.
    Taken altogether, the results are simple. I have a slightly degraded battery (and I think I know why). And the cars display of range does not reveal it. I wish that I had known that this was possible before I bought the car.

     
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  9. sorka

    sorka Well-Known Member

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    Your inability to face facts and move on is very unfortunate.

    There are two issues here. 1) Your displayed rated mileage which is exactly 100% what it should display based on the kwh available by your battery. You're battery has degraded some which is an unfortunate reality with revision 1 of your 90 kWH battery.

    2) You're getting 15% less than your displayed rated range. This is due to either your driving habits, environment, or alignment. Go get your alignment checked and post the before/after sheet here. Unless you're a lead foot or driving in freezing weather, I'm betting this is your issue. The issue of you not getting the rated range you expect can't be fixed except with a new battery.
     
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  10. ucmndd

    ucmndd Well-Known Member

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    In this day and age I should stop being surprised about the continued degradation of what constitutes a “fact” in peoples’ minds.
     
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  11. swegman

    swegman Active Member

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    Peters Lucas (OP), I'm sorry, but you are mistaken, and the sorka and the other posters are correct. To confirm that you are mistaken, do the following:
    1. Find out what the energy usage is for your SPECIFIC model that is used by the EPA, such as 285 WH/mile.
    2. Reset your odometer. Take a long distance trip driving such that your energy usage corresponds to what you noted in 1, above.
    3. Subtract the range indicated on the car at the end of the trip from the range indicated on the car when it was charged to 100 percent. This corresponds to the battery usage for your trip. For example, assume a 100% charge indicates a range of 290 miles and at the end of your trip it indicates 200 miles is left. Thus you used 90 miles for your trip. Compare this number to the distance shown on the odometer for the trip. They will match, assuming you adhered to whatever driving speed corresponded to the energy usage noted in 1, above.

    My lifetime energy usage in my 2013 P85 is 346 Wh/mile, due to certain factors I will not put in print. Thus I usually get less actual driving range than indicated by the car. However on those occasions where I had to drive 250 miles between chargers, I made sure not to exceed the EPA specified energy usage for my car, and the battery range indication matched precisely with the distance I drove.

    Also, you may not realize that you do not have full access to your battery. A portion of the battery is kept in "reserve" to prevent bricking of the battery. So while you have a 90 KWH battery, you can only use 80 something KWH of it.
     
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  12. animorph

    animorph Active Member

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    As far as I've seen, the reported Wh/mile is even less accurate than the rated range. It doesn't include some auxiliary power usage. Calculations of battery capacity using Wh/mile reported on the dash have always been off compared to expected/reported battery capacity. So why assume displayed Wh/mile is more accurate than displayed rated miles?

    Battery degradation shows up as loss of rated miles at whatever your normal charging limit is. That may or may not be super accurate, it is an estimate, but it's what we have that's easily accessible.

    And of course those rated miles displayed are EPA miles, not a prediction of your personal range on your next trip.

    Plenty of long threads on this topic, including new owners of Model 3's working this all out again for the Nth time.
     
  13. AWDtsla

    AWDtsla Active Member

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    No, it's not that it doesn't include it, it's just that it's WRONG. I'm not surprised someone trying to do the math is not getting values to line up, because they don't.

    Rated miles is simply a percentage with a higher gradation. It's not about accuracy, it's about knowing the exact conversion factor, which never changes (so far).
     
  14. jaguar36

    jaguar36 Active Member

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    Nope!

    At this point further arguing is a waste of time. You've been presented with all sorts of information showing why you are incorrect, by all sorts of people. You can continue to believe whatever you want, but for anyone else please understand that:

    The rated range displayed by the car does take into battery degradation.
     
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  15. Peter Lucas

    Peter Lucas Member

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    The variety of information attempting to show that I am incorrect, is incorrect.
    Specifically:
    1) That my full charge rated range would be 295 miles if the battery had no degradation. I have demonstrated that this is untrue in a previous post. Pre-refresh Model S 90 D's are commonly (mostly?) found to display a max charge rated range of 270 to 285 miles. You can look that up yourself if you doubt that.
    Actual Real-Life Range of 90D and P90D ? | Tesla
    2) That my decreased range is due to a higher than rated consumption rate. Consumption rate, wh/mi, is easy to factor in (or out) of a calculation. On my long trial run my consumption rate was 306 wh/mi. A Tesla representative told me that for my car, a pre-refresh S90D, the value used for range calculations is 324 wh/mi. This lines up well with the observations of many 90D owners of their maximum ramge and a useable battery capacity of 85 kwh. There seems to be a belief among some critics here that 285 wh/mi is the number actually used for range calculations. It appears that this became the value that Tesla began to use for the late 2016's. This enabled them to advertise a 300 mile range for the "new" 90D.
    In any event, neither the advertised nor the displayed range is realistically obtainable in my car. All the while, the displayed range is similar to that of other similar 90D owners.

    Thus it can be concluded (can only be concluded) that my car is not factoring in the degradation of the battery when displaying full charge range.
     
    • Disagree x 2
  16. Peter Lucas

    Peter Lucas Member

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    Yes. Absolutely correct.
    The little battery display which can be set to display either SOC percent or remaining range is completely useless and deceiving when set to display range. When set to display SOC %, I can double the displayed number for a close estimate of miles remaining. This is for a driving style of about 350 wh/mile. However, a 200 mile max charge range is much less than what was advertised.

     
  17. Peter Lucas

    Peter Lucas Member

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    I thought about front end alignment as a cause of high energy consumption (as well as tire pressure). But I get the same energy consumption before and after replacement of the front suspension forelinks. And they told me that they did an alignment as part of the forelinks job. And I have the tire pressure at 45 psi. So that should be good. I do push hard on that right pedal at times. Hard to deny myself that pleasure on occassion. And it is needed sometimes. I have taken some test trips where I deliberately drove like an old lady. Avoiding the higher speeds and the higher accelerations. My consumption didn't go down much. Maybe from 350 to 340 or similar.
    I am willing to accept some range loss due to my driving style. But the shortfall is much greater than can be accounted for by my driving style.
    During the research and purchase process I was told that 275 miles was a realistic range. It is not realistic in my car. Without trying to be frugal, the range is about 200 miles. If I am somewhat careful, maybe 220. And the full charge rated range continues to show something around 275 miles.
    This is information that I would have appreciated before the purchase.

     
  18. AWDtsla

    AWDtsla Active Member

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    Impact is minimal. Even in my car, one hard acceleration is no match for a long drive. Try and see how high you can make the consumption, it's actually quite difficult - then you discover the self-flagellation over how bad your reported OR real consumption is totally undeserving. I've even done things as silly as doing 3 consecutive quarter miles runs at a drag strip, then driving 50-60 miles home, and you barely notice the difference in overall consumption by the time the drive ends.
     
  19. GatorGuy

    GatorGuy Member

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    1) You have not demonstrated that a new battery on a 90D is typically 270 miles. Even your link that you posted directly contradicted it. Not a single person said that they got 270 miles when the battery was new. One person said it got 270 when he bought the car but did not say that the car was new. However, there are multiple examples in that thread of new 90Ds getting much higher than 270 new.

    As already discussed the P90D is not comparable. Even that thread shows the disconnect between the 90D and P90D.

    2) Your biggest mistake is the 324 wh/mi. Your only evidence is that a Tesla employee told you this. It works out to your math and what you think is happening to your battery. However, 324 wouldn't work for anyone else and thus can't be correct.

    Looking at this thread: Calculate usable battery capacity based on rated miles values

    It correctly states for the Model S 90D the consumption is 285 wh/mi. It also interestingly states that the consumption for the Model X 90D is 320 wh/mi which makes 100% sense. The tesla employee was probably thinking of the Model X rather than Model S.

    The link also shows how unrealistic that number is because if the 90D has a consumption of 324, then the Model X 90D must be even higher as well as the Model S 100D, P100D, Model X 100D and P100D. The math simply doesn't work.
     
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  20. Peter Lucas

    Peter Lucas Member

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    Swegman:
    A couple of things.
    Your instructions to calculate the battery useage on a trip are the long way around. The car has a direct display of "kwh used since last charge". By the way, this number can be used to calculate your total battery capacity.

    You have been able to go 250 miles in your P85? No way could I go that far in my 90D with any realistic driving style. Good for you. Confirms that my battery is degraded.

    Useable or available battery capacity for the 90 kwh battery has been described as 80 to 85 kwh. There is some reserve at both the top and bottom end. Charging to the highest possible voltage or discharging too close to 2.5 volts is really bad for these batteries. So Tesla has built in headroom and reserve room. I understand this.

     

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