Is my math correct?

Discussion in 'Cooper SE' started by sacharama, Nov 23, 2022.

To remove this ad click here.

  1. sacharama

    sacharama Active Member

    48F sunny

    Climate control set at auto at 66F with AC off

    Sport mode

    Drove 28 miles

    Used 21% of battery (based on the % shown at the bottom of the dash display)

    28/21 = 1.33

    1.33 x 100 = 133 miles range

    133/28.9 = 4.6 miles/kwh

    Is that correct?
     
    Last edited: Nov 23, 2022
  2. To remove this ad click here.

  3. P&T

    P&T New Member

    Yes, but with a caveat. Just with town/errand driving 160 miles isn’t hard. But, speed, temp, and driving style can cause variations. We’ve gotten 130 miles easy with mixed driving, but I would recommend using two to three full charging cycles to see what the true range is for you and your mini. The range estimates on the screen aren’t that accurate.


    Sent from my iPhone using Inside EVs
     
  4. teslarati97

    teslarati97 Well-Known Member

    Mathematically possible, but statistically you would be applying a linear regression to indirectly determine your efficiency.

    It's probably better to calculate the efficiency directly as 28 miles divided by kWh used (28.9 * 0.21 of the usable kWh).

    This is like saying in the World Cup, USA was up 1-0 in the first half against Wales. So extrapolating the data would be 2-0 USA for the entire match, and on average USA is 1 goal per half, when in reality the Welsh drew and the game ended in a 1-1 tie (0.5 goals per half on average). Probably not so great with a sample size of 1, but oh well.
     
    SameGuy likes this.
  5. AndysComputer

    AndysComputer Well-Known Member

    You are correct in terms of range.
    However to allow for slightly non linear battery percentage reporting you should do the same calculation over a much greater battery range.
    That said, your range seems very plausible, I don’t know the conditions but in green mode I get 130 on the highway and 170 around town…

    You calculate efficiency the same way I do but the I only problem is that we don’t know if 100% to 0% means consuming the usable 28.9kWh as there is a buffet below 0 which may or may not come out of that meaning you use less than 28.9 to get down to 0. That said… this would simply mean our calculated efficiency figures are worst case, the real number may be better.

    Mini are really sandbagging the range and efficiency numbers of this car, and while it’s great to under promise and over deliver, the sticker range figure does put a lot of people off who day “I just wish it had a little more”, when I know it does!
     
  6. teslarati97

    teslarati97 Well-Known Member

    While we can't control the weather, driving style and tire/wheel choices can certainly impact the range/efficiency. I'm just thankful that I don't have a 3.15kWh (~3% on 105kWh) daily vampire drain on the MINI as that would be almost 11% loss (per day)!
     
  7. To remove this ad click here.

  8. GetOffYourGas

    GetOffYourGas Well-Known Member

    I have found that Mini has a few percent capacity hidden at both the top and the bottom. For example, I drive 3 miles and the car still reports 100% SOC. After another 3 miles, it reports 97% and proceeds to lose about 1% per mile (give or take).

    On the low end, there was a video on YouTube where they drove the Mini for something like 20 miles on “0%” remaining.

    Because of this, I too recommend using a wider range of charge to estimate. This will reduce the skew due to those hidden kWhs.

    At the same time, would those people really bite of the advertised range was 130 miles with caveats that it will be less under less ideal conditions? I think they made the right choice. Fewer customers maybe (maybe not) but far more satisfied and likely to return!




    Sent from my iPhone using Inside EVs
     
    polyphonic likes this.
  9. teslarati97

    teslarati97 Well-Known Member

    That should be a carwow test in the UK. The extra range after 0% SoC is a mixed bag of BMS cell/module rebalancing and slow city driving.

    I think Tyler Potter was able to get another 3 miles in limp mode (made it home!) after the MINI stopped the first time from highway driving.
     
  10. Qisl

    Qisl Active Member


    Toyotaru seems to have taken this approach. There have been Danish, Swedish, and Norwegian reports that the BZ4x is getting around half of the mileage that Toyota said that it would get. Granted, it is winter there now, but ...
     
  11. SameGuy

    SameGuy Well-Known Member Subscriber

    YUL
    I need more info on this, care to share some links? My best friend placed an order for a Busyforks before the wheels fell off, but after the reports of slow fast charging. He’s still not dissuaded, regardless of how unremarkable — and now problematic — it seems.
     
  12. To remove this ad click here.

  13. teslarati97

    teslarati97 Well-Known Member

    I think he's referring to elbil24's review. One thing to point out that the busyforks only has a Guess O' Meter and no battery SoC % display. That is disturbing...
     
    SameGuy likes this.
  14. Qisl

    Qisl Active Member

  15. teslarati97

    teslarati97 Well-Known Member

    EPA rating says 367km for dual motor and WLTP is 461km so when Danish FDM real world tested 215km that is very reasonable with all the nice cabin comforts and the "new front-seat radiant foot-and-leg heater". Now if they tried at -22F and lower, that's a different story.

    elbil24 tested at 46.4F or 8C and FDM at 39.2F or 4C
     
  16. Qisl

    Qisl Active Member

    I could be wrong, but I think the American solterra lacks the front-seat radiant foot-and-leg heater. Perhaps Subaru pulled it for this very reason.
     
  17. sacharama

    sacharama Active Member


    Even using the lower EPA rating, that's more than 40% less. How is that very reasonable? That's equivalent to the SE having only 67 miles full range at 39F with climate control, seat heater and heated steering wheel turned on running on winter tires. That's unacceptable.
     
    SameGuy likes this.
  18. teslarati97

    teslarati97 Well-Known Member

    I thought using BYD Blade LFP batteries was the hottest thing on the market...except LFP hates cold weather (needs active battery heating...). Nobody complains about the Tesla Model 3 SR using LFP, so why give Toyota such a hard time?

    Reasonable is in light of the lithium anode choices, extra radiant heating, AND lack of SoC % display!

    I will get 67 miles of full range probably at 14F with highway driving and probably 49 miles of full range at -30F in the SE.
     
  19. sacharama

    sacharama Active Member


    But we are not talking about 14F or -30F, we are talking about 39F.

    You will get a lot more than 67 miles at 39F in mid mode with climate control turned on with your SE.
     
    SameGuy likes this.
  20. teslarati97

    teslarati97 Well-Known Member

    Absolutely! I get 140+ miles in the summer in the SE and if I could get 45+ miles in -40F weather I'd be happy.
     
  21. sacharama

    sacharama Active Member

    But the point is not about whether or not you could get 45+ miles at -40F.

    The point is about you stating that it's very reasonable to lose 40% of range at 39F.

    So I commented that it's very unreasonable to lose that much range at 39F as it would be equivalent to the SE having only 67 miles range at 39F.

    But then you responded by stating that you will get 67 miles at 14F.

    Then I responded that the temperature we are discussing is 39F and not 14F. In addition, getting 67 miles at 14F actually supports my point that getting 67 miles at 39F is unreasonable.

    Then you stated that you will get 140 miles in summer and 45 miles in deep freeze.

    You provided a series of facts but none of them
    supports the notion of getting 67 miles at 39F is very reasonable.
     
  22. teslarati97

    teslarati97 Well-Known Member

    We seem to be at an impasse if 133.5 miles at 39.2F on a bz4x is very reasonable with all the nice cabin comforts and the "new front-seat radiant foot-and-leg heater" (w/ active battery heating/cooling) and a hypothetical 67 miles at 39F on a SE is unacceptable.

    If you read the FDM article:
    BZ4X har ikke den sædvanlige måler, der viser den resterende strømmængde i procent.

    De ni procent (mindre eller lidt mere afhængig af en række forhold) i reserve kommer oven i, at batteriets brugbare kapacitet er langt fra de 71,4 kWh, der står i brochuren. Det er brutto.

    Desuden har Motor konstateret, at den angivne rækkevidde er markant lavere, når varmeapparatet/klimaanlægget er slået til.​
     
  23. SameGuy

    SameGuy Well-Known Member Subscriber

    YUL
    More of a disconnect than an impasse. I don’t disagree with the poster above, getting 50% of the WLTP range at 4°C above zero is ludicrous, even with all the creature comforts activated. Why is Toyota being so cagey about the facts?
     
    sacharama likes this.

Share This Page