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Winter Cold Battery Efficiency

Discussion in 'Cooper SE' started by Puppethead, Dec 29, 2020.

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  1. Dec 29, 2020 #1
    Puppethead

    Puppethead Well-Known Member

    Twin Cities, MN
    I finally got a real winter drive in, and the good news is the SE is handling the cold temperatures much better than I expected.

    I went for a 55-mile drive in 10-12 ºF temperatures and got 3.4 mi/kWh (29.4 kWh/100 mi). Roads were clear and almost no wind.

    I had cabin heat set to 68 ºF, seat heat on full, no A/C, no defrost. The car was at 100% SoC when I left and had been climatized about an hour before the trip (while plugged in inside an unheated garage). Most of the driving was freeway speed with cruise control, and I was in green mode the whole time. I did have a half-hour stopover halfway through the trip, where the car sat exposed outside.

    55 miles with 49% SoC left indicates about 100 miles of range when the temperature is well below freezing, which is only about 10% drop in range. I was expecting less than 80 miles of range at temperatures this low. I think the GOM (guess-o-meter) is pessimistic at these low temperatures.

    winter.PNG
     
    Last edited: Dec 29, 2020
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  2. Dec 29, 2020 #2
    GetOffYourGas

    GetOffYourGas Well-Known Member

    Syracuse, NY
    Wow, that is fantastic! My Bolt is currently seeing about 40% less range in temps just below freezing (25-30F).

    What tires do you have on the car?


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  3. Dec 29, 2020 #3
    insightman

    insightman Well-Known Member Subscriber

    Ann Arbor
    You've gotta respect anyone who can spell "Hakkapeliitta."
     
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  4. Dec 29, 2020 #4
    Lainey

    Lainey Well-Known Member

    Way better than expected! It looks like mine will be delivered during the bitterly cold so was expecting about 80 miles total!
     
  5. Dec 29, 2020 #5
    GetOffYourGas

    GetOffYourGas Well-Known Member

    Syracuse, NY
    My car will be delivered to upstate NY in January. And it is an 86 mile ride home. Something tells me I will get to see the car’s cold weather DCFCing performance along the way.


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  6. Dec 29, 2020 #6
    GetOffYourGas

    GetOffYourGas Well-Known Member

    Syracuse, NY
    I missed that comment, was it from another thread?

    I hear those tires are pricey but worth every penny. I have a set of Michelin XI3s on my Bolt. They are pretty good, and I would gladly buy them again for the Mini.


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  7. Dec 29, 2020 #7
    Lainey

    Lainey Well-Known Member

    At least mine is just in another suburb of our major city. Good luck!

    I realize this year I likely won't have time to do winter tires. So hope for avoiding snowy days (they clear roads quickly here)
     
  8. Dec 29, 2020 #8
    Puppethead

    Puppethead Well-Known Member

    Twin Cities, MN
    Yes from a different thread, when I was waiting forever for my snow wheels. And I have Finnish in the family, so the word isn't too alien to me...

    I got the tires from Discount Tire. $168 each, so not cheap. But these are designed with electric cars in mind, with a low rolling resistance.
     
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  9. Dec 29, 2020 #9
    insightman

    insightman Well-Known Member Subscriber

    Ann Arbor
    I have Hakkapeleetias (drat!) on our Clarity Plug-In Hybrid, but opted for Michelin XI3's on our MINI Cooper SE because members of the Inside EVs Clarity forum said the Michelins were quieter. They're not much, if any, quieter, in my experience, but the Clarity has better sound-deadening (including $1100 @ rims with sound-deadening devices) than the Cooper, so that may make the Hakapeliitass (ugh!) seem quieter than they would be on the Cooper.
     
    Last edited: Dec 29, 2020

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  10. Dec 30, 2020 #10
    GetOffYourGas

    GetOffYourGas Well-Known Member

    Syracuse, NY
    Sadly there is no mini dealer in my major city (Syracuse, NY), so I have to travel to the next one over (Rochester, NY). Fortunately there is an EA station about half way between the two (Waterloo, NY). And yes, they also do a great job of clearing snow up here. But I think the car comes with performance summer tires so I am hoping for a sunny day (unlikely!)


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  11. Dec 30, 2020 #11
    Lainey

    Lainey Well-Known Member

    I'll have to see what is on them. All season can be doable if I can avoid going out while it is actively snowing. If it gets real bad, I may just opt for cheapest cheap non Mini rims with snow tires. Given my work is from home I can hopefully avoid. I could have possibly planned this when I bought the car, but given I was thinking it could be March I didn't put thought until it was very late to order anything.

    My car is on the boat that is docking today. Watching it go up the Patapsco river right now.
     
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  12. Dec 30, 2020 #12
    GetOffYourGas

    GetOffYourGas Well-Known Member

    Syracuse, NY
    I could deal with all-seasons, I guess. Although they really are the worst of both worlds - mediocre in both Summer and Winter. I'd rather have two sets of tires, and I've never seen a car come off the lot with winter tires.
     
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  13. Dec 30, 2020 #13
    Puppethead

    Puppethead Well-Known Member

    Twin Cities, MN
    Another thing to consider is getting winter tires and have them mounted on your existing wheels, just match the size. That could be done really quickly, and then you could get snow wheels to mount them on for next season. Or just keep swapping the rubber each season, although that would likely cost more each time than a wheel swap.
     
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  14. Jan 6, 2021 #14
    vader

    vader Well-Known Member

    Just thought I'd add the opposite perspective. I live in a hot climate - it rarely gets below 10C (50F) ever. My efficiency since day 1 is 12.4kWh/100km which equates to 5miles/kWh. The higher the temperature, the less dense the air is - there is a 10% difference between 0C and 30C. I am getting 250km range (155miles) which makes the EPA 110 rated range look, well, just plain wrong. Maybe it can be attributed to warmer temps - although I always have the aircon on - set to 21 or 23C depending on how I feel. I didn't notice any difference in range between winter (well what we call winter - about 25C daytime temp) and summer (35C +). If I drive like a grandmother (no offence to grandmothers :) ) I have seen 10.5kWh/100k (6miles/kWh). I did try once to see how uneconomically I could drive, but still only topped out at 14.5 (100kph limit, foot flat acceleration from lights etc).

    Is there a temperature where the efficiency starts to decrease?
     
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  15. Jan 6, 2021 #15
    Puppethead

    Puppethead Well-Known Member

    Twin Cities, MN
    Most definitely, but I bet it's going to be well over 100 ºF/ (37.8 ºC?). If you've seen Youtube videos of the SE on the race track the batteries suffer from heat effects due to the hard driving. But I'd hope the heat pump can keep the batteries reasonably cool for normal driving even in warm weather.

    In the summer for me when it was 80+ ºF I was getting the kind of range you are seeing, which I think is awesome. I'd much rather have a car outperform its specs instead of underperform, which seems to be the common case with other manufacturers.
     
  16. Jan 6, 2021 #16
    insightman

    insightman Well-Known Member Subscriber

    Ann Arbor
    Has anyone verified that the heat-pump can either heat or cool the battery? I thought it provided only cabin comfort.
     
  17. Jan 6, 2021 #17
    Puppethead

    Puppethead Well-Known Member

    Twin Cities, MN
    I based my comment on how the heat pump for my geothermal system in my house works. It does both heating in the winter and cooling in the summer.

    I can't imagine MINI engineers wouldn't take advantage of that, but I don't know of any technical discussion anywhere. But definitely there's something in the SE dealing with battery heat and sending it somewhere.
     
  18. Jan 6, 2021 #18
    fizzit

    fizzit Active Member

    I found that the AC didn't work when I was fast charging in the summer. So that's a clue to how the system works. I'm curious if the AC compressor is separate from the heat pump, since they perform the same fundamental task but I could see cases where you'd want both.
     
  19. Jan 6, 2021 #19
    insightman

    insightman Well-Known Member Subscriber

    Ann Arbor
    That's very interesting. Is it possible the heat pump that transfers battery, motor, and electronics heat to the cabin also functions as the air-conditioner? I assumed they were separate devices.
     
  20. Jan 10, 2021 #20
    vader

    vader Well-Known Member

    Did you try to precondition using the app? I was using a 50kW charger in 35C temperatures and preconditioned the car using the phone app. Added a few minutes to the charge time.
     
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