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Lost 40 miles range on a 11mile regular journey?? New Model 3

Discussion in 'Model 3: Battery & Charging' started by BubblegumPete, Sep 27, 2019.

  1. BubblegumPete

    BubblegumPete Member

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    #1 BubblegumPete, Sep 27, 2019
    Last edited: Sep 27, 2019
    Ok so today I gave a friend a lift to pick up his Model 3 in my model 3 performance with the 20 inch alloy wheels.

    The service centre is only 10 miles or so and I left to go on a charge of 255 miles.

    The journey there was just regular speeds ranging from 20 - 50 miles per hour. There was a bit of motorway for around 10 minutes but because of traffic I don't think I averaged over 60 - 65 miles per hour.

    We were in the service centre for a good couple of hours but when I left I had a look at my battery and was shocked to see it only had 205 miles range left. I looked at my Watts per mile and it said 390! Most of the driving was in traffic so I just can't see how I managed to be draining the battery that much and at relatively low speeds.

    Weather was fine and temp outside about 19c. I did have air con on but fan was set to about 6 or 7. My car has only done about 3500 miles.

    I watched the battery on the way back and it seemed to drop as expected but I think I need to do some more tests.

    The only thing I could think of is that there were a lot of people in the car park and sentry mode was on. But I can't see how that could drain the battery so much.


    Any ideas?


    Peter
     
  2. KenC

    KenC Active Member

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    Strange. At 390Wh/m, you used 16 miles of range in about 10 miles. The remainder, 34 miles, even with Sentry wouldn't be used in a couple hours. At most, you might use 3 miles in a couple hours. So, 30 miles are unaccounted for.

    What screen are you looking at for range? You aren't mixing up the energy gauge with the Estimate based upon driving are you?
     
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  3. SigNC

    SigNC Active Member

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    hot and in the sun with cabin overheat protection enabled?
     
  4. AlanSubie4Life

    AlanSubie4Life Efficiency Obsessed Member

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    #4 AlanSubie4Life, Sep 27, 2019
    Last edited: Sep 27, 2019
    This is a good thought. I can't explain this otherwise.

    205 miles left would be what the range estimation screen (the big screen with the graph on it) would indicate if:

    You had:

    255rmi - 11mi * 390Wh/mi / 230Wh/rmi = 236 rmi left (next to the battery gauge) and your average consumption (as indicated by the solid horizontal line on that graph) of the last 30/15/5mi (or whatever you had chosen in mi or in km) was equal to:

    230Wh/rmi * 236rmi / 205mi = 265 Wh/mi

    rmi = rated mile

    These are rough calculations (the 230Wh/rmi constant may be off by 1%), but it's close. But it is certainly possible in the stated situation to end up with this result on the range estimation chart (though most likely you would have had to have the range chart set to last 30 miles, or last 5 miles (less likely) to make the numbers work).

    If you were seeing 205rmi on your battery gauge (not the range chart), that's an awful lot of range loss - there could be some sort of BMS estimation issue or something but I've never seen such a thing to that degree (I've seen sudden 5-10 mile increases).

    390Wh/mi is pretty darn high even for a Performance Model 3 with PUP though for the stated journey details. Were you using the heat? You are in the UK, winter is coming. ;)
     
  5. kailm

    kailm Member

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    If you have cabin heat protection on AC, that is your battery drain. Also 20s are pretty bad for efficiency, they should change the BMS to match your wheels config. 20s are super heavy, while the estimation they give is probably based on Aeros!
     
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  6. AlanSubie4Life

    AlanSubie4Life Efficiency Obsessed Member

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    I disagreed with it because the cabin overheat protection would not result in the stated level of drain over the stated timeframe.

    If the OP were looking at rated miles, hard to explain this. If he were looking at estimated range, it seems conceivable you could get this result.
     
  7. T3slaOwner

    T3slaOwner Member Extraordinaire

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    I see this crap all the time with my model X. In an ICE I have some idea of my fuel status at all times. With the Tesla I never have any idea of what to expect. Often this is not a Wh/mi issue, rather some portion of the battery charge just goes away with no accounting. I've seen charges drop by as much as 10 kWh more than the mileage attributable consumption over a two or three day period.

    It's like the Robert Palmer song Simply Irresistible, "She's so fine, there's no telling where the money goes"

    I've given up worrying about it. Supercharging is free, so it's not my money. My only concern is being about to get to a charger before I run out and everyone simply talks about the trip navigator. That is of no value when I at a friend's house with no way to plug in and no Supercharger for 50 miles. I can't tell you how many times I've had to find level 2 charging and spent an hour getting enough to make it to a Supercharger. Driving around town and especially when the car is not being driven, it seems like it's simply irresistible.
     
  8. ewoodrick

    ewoodrick Well-Known Member

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    There are a number of times when the numbers may seem weird, just them be. And make sure that you don't play with the car.

    Look for the longer term numbers.
     
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  9. Celledral

    Celledral Member

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    Please keep in mind elevation and headwind can drastically take a toll on your range. That’s the biggest factor besides the heater or heavy acceleration.
     
  10. AlanSubie4Life

    AlanSubie4Life Efficiency Obsessed Member

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    That’s not the issue here because (allegedly) the rated miles used and the Wh/mi usage over 11 miles don’t line up. The question is which “miles” of range the OP was referring to - rated miles, next to battery icon, or the estimated range.
     
  11. TimothyHW3

    TimothyHW3 Member

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    #11 TimothyHW3, Sep 27, 2019
    Last edited: Sep 27, 2019
    Ok, there are a lot of red flags and your consumption is totally normal, but let me explain why.

    1. The obvious - you have a P with 20 inch, this is the most inneficient model of all. Tesla's rated consumption, which you see on the dash is for 153Wh/km or around 241Wh/mile. But on a P that number is harder to get as it is on let's say LR AWD 18", but both cars are rated the same.

    2. You were driving in traffic. Even though the EVs are far better when driving in traffic than ICE cars, you are still consuming more than if you were driving with AP constantly at 70mph like Bjørn Nyland is doing. Then we have the AC/HVAC, which was constantly running and is huge consumption source hence 3.

    3. HVAC - you said you had it "only at 6 or 7"? This is "only" 2-3 steps down from max! I made a video explaining how this affects the range, especially when driving such short distances. I know it is a bit technical, but if you want to understand how to reduce consumption nor what your car is doing, you have to watch it. It is not very hard to understand either.




    At around 3:30 I explain your exact scenario and in about 7 minutes I explain how you can dramatically lower your consumption, by using the proper AC setting. But watch it in full without skipping to understand everything.

    If I take your values of HVAC set to 6-7 this is about 3 to 5 kW. To transfer that into wH/miles I need better numbers ( it is hard to make out really how fast you were driving, because you first say 20-50mph, then 10 minutes highway, then all of a sudden an avg. Of 60mph for the whole trip...), but let's say you drove for about 20 minutes each way, 40 minutes both ways, you added about about 2 to 3.5 kWh to your consumption. If we turn that back into rated miles, just the AC on that trip accounted for about 7-8 miles to 12-15 miles, depending on the outside conditions. If you turned off AC(AC button off, HVAC on manual with AC off, blowing air) and left the system on manual at 7-8 you would have saved these rated miles. Or turn AC on Auto, this saves a bit too, since the HVAC controls the AC better than having it sit constantly at 7.

    4. Then we have sentry mode. Sentry mode is rated at about 250-300 W and if it triggers a lot, even more.

    So there you have it. When you know what the car is doing and what is causing the consumption, you can lower the consumption by a lot. I would suggest to dive in some YouTube videos from Bjørn Nyland to get a better understanding of the car. You can also check out my videos, I have some road trips in there where I did around 5000km worth of driving coming up. I also have a Norway trip coming soon.
     
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  12. AlanSubie4Life

    AlanSubie4Life Efficiency Obsessed Member

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    This is about right, but in terms of what the trip meter shows, it’s about 230-234Wh/rmi for all Dual-Motor Model 3s, assuming no BMS weirdness. You can easily measure it yourself if you want, of course. But it has been done by others already...there are some threads. Your assertion of 75-76kWh of available energy to 0 rated miles is correct, of course. (No, 310rmi*230Wh/rmi does not match - but that is just the way it is.)
     
  13. TimothyHW3

    TimothyHW3 Member

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    Not sure what your 230 is based on, real life or rated range? I am talking about rated range, which is exactly 241 to 245 depending on battery capacity and BMS. This is the hard coded value that gets you to 310 miles.
    And thisnis why the 241* 310 matches the battery capacity.(I am actually thinking in km, I thinking is more accurate. 151-154Wh/km*499km)

    Available energy is a funny thing - we don't really know what that value is, yet. We have obtained OBD II Data via scanmytesla and from what we see, Tesla is calculating the buffer into the available energy. Meaning, a fresh battery from the factory usually has around 77kWh nominal pack(measured on 3 cars after delivery) with about 3.5kWh buffer, which is 73.5kWh available to the driver. With time the nominal full pack as well as the buffer is reduced. We are seeing a fast degradation at about 10000miles at 74.5-75.7kWh including the buffer which is then lowered to about 3.3kWh

    Tesla is calculating the rated miles based on the nominal full pack though, including buffer. Not just the nominal pack excluding buffer like it should be. Not sure why, might be an EPA thing or a way to boost miles range.

    So we are not sure if you actually go to 0%, wether the 0km(0%) is at -73.5kWh or -76-77kWh. We are trying to figure that out.
    But from what we see, it might not be including the buffer. So technically, even if you drive at the rated Wh per mile, I don't think you can make the 310miles from 100%-0%. You have to be more efficient to make it.

    As for real life consumption, like I said, if you drive a P, a 19" LR AWD and 18", at same speed same road same time, the consumption will differ. But the rated consumption is the same for all. Which is the part that most people don't understand, a bit misleading by Tesla.
     
  14. AlanSubie4Life

    AlanSubie4Life Efficiency Obsessed Member

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    You can measure the constant (if you are careful). Don’t worry, you do not have to believe me - you can do it yourself. Do a long trip in drive without stopping, starting with a battery at thermal equilibrium (same temp at start and end of trip), measure “delta rated miles,” measure the trip meter kWh (miles * Wh/mi). Then divide kWh/(delta rmi). For AWD you will get around 230Wh/rmi.

    Here is a discussion about all of the constants and how they differ:

    Constants Summary

    If you look at the several posts prior you’ll see how it is backed up by API data as well. Lots of discussion. It is confusing, but it is not nonsense - it is just based on empirical observations.

    The summary is that the in-car trip meter reads about 5% low relative to the charging energy page. Indeed, when charging, it is 245 Wh/rmi for the AWD. I don’t know why Tesla does it this way.
     
  15. TimothyHW3

    TimothyHW3 Member

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    #15 TimothyHW3, Sep 28, 2019
    Last edited: Sep 28, 2019
    I think you are still confusing a lot of things, mainly the EPA constant Tesla is using for the mileage you see when charging and charged, and the actual consumption. These are two totally different things. The constant can' t be measured during driving, because the BMS will also use some of the buffer.

    This Is why your "calculation" 310*230 doesn't add up to anything meaningful, because you are guessing.

    Also, you are using TeslaFi for measurement which is innacurate as TeslaFi is also guesstimating based on kWh they observe being taken out or pumped in. But they don't know how much heat loss there was and how much of the buffer there is or being used or even what the total available capacity is. TeslaFi is a useless thing that uses your battery. The only way to know what is going on inside the car is to get access to the OBD II CAN bus, which I have.

    Like I said, I am reading the actual kWh reported from the BMS via OBD II, same as the car itself.

    On a brand new Tesla, we have exactly 77kWh with 3.5kWh buffer. For reasons unknown(mostly marketing) Tesla is using the full capacity to calculate EPA inside the car. I will use metric - 77kWh/500 is 154Wh/km or I think around 246 rounding error Wh/m.
    This is the constant Tesla is using for all cars dual motor (P and AWD) which means that you have only 478-480km available roughly as there is 3.5kWh buffer.

    Now, we are getting reports that Tesla will actually unlock these 20kms if you end up at 0 miles/km. Think of it like this. If you drive with exactly 154Wh/km for 480km your car will report 0 remaining, even though you are hitting EPA rated consumption perfectly. This is due to the buffer being included in the calculation.

    Now, if you wish, you can test this yourself and you will come to the same conclusion, but bare in mind that your car has degradation and most likely has nominal full at 75kWh minus buffer so only 71kWh.

    I urge you to get a OBD II cable and see for yourself if you don't believe me.
     
  16. mact3333

    mact3333 Member

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    Not surprising at all....I am averaging 325 war/mile....I’m prob getting like a true 220 mile range on my LR awd car...I drive normally but have 20 inch after market wheels.
     
  17. xxxholic

    xxxholic Member

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    My car was in the shop for over 4 weeks and its only a month old - I went from 310 miles max charge down to 288 mile max charge. Would that happen because my car wasn't being properly charged for over a month?
     
  18. AlanSubie4Life

    AlanSubie4Life Efficiency Obsessed Member

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    #18 AlanSubie4Life, Sep 28, 2019
    Last edited: Sep 28, 2019
    No I am not.

    I agree with this. It is (approximately) what I said in the other thread, in fact.

    The trip meter reading matters in this context because that is what people typically report. It is important to see how it relates to rated mile use. And how it relates to how much energy you have to put back into the car to restore your rated miles.

    The trip meter constant I quoted is indeed relevant - you just can’t use it to determine your battery capacity. You can use it to predict rated mile usage.

    You should try measuring it sometime and compare to the API and CAN bus data. You’ll find my number is very close.
     
  19. TimothyHW3

    TimothyHW3 Member

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    Well, it is close but not accurate. That is the problem. This is why, like I said, your constant 230*310 doesn't add up, like you noticed.

    Like I said, the constant in KMs is 154 or 153 depending on the rounding and it adds up to exactly 77kWh which is the base capacity. This is why when you have 75.7kWh, like I do with degradation, I only get around 495kms shown when I charge to 100%.
    This is why the constant adds up perfectly to what is shown on the battery gauge and with the kWh reported from the CAN.
    153*495 is 75.7
     
  20. AlanSubie4Life

    AlanSubie4Life Efficiency Obsessed Member

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    So, let’s do a test then:

    If you travel 100 miles at 245Wh/mi as indicated on the trip meter in an AWD, how many rated miles will you use on the gauge in the car?

    The answer is 106-107. Again, no need to believe me - you just have to check it yourself.

    I have no disagreement with you about the amount of energy available in the pack.
     

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