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Realistic Range Expectations in Crummy Winter Weather

Discussion in 'Model S: Battery & Charging' started by jeffnorman, Nov 11, 2013.

  1. jeffnorman

    jeffnorman Member

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    We had our first (extremely light, melting) snow of the season here in Chicago today, and I was a little shocked when on a 7 mile drive my average wh/mile read 703!!!?? Temperature was not terrible, around 32F. Wind was light. Rain turning into snow. I had interior temp set at 70F, and I did use the rear defrost to clear snow. I also kept my seat warmer on. None of which should have affected the consumption all that much.

    I am hoping that my power consumption was an anomaly (some kind of vampire loss getting added in) but this read was FAR higher than my previous high the identical short trip (previous high was 410 wh/mile). This is city driving, with lots of stop and go, so getting upper 300's to 400 wh/mile is not bad (on Lake Shore Drive and on the freeway I usually am well under 300 wh/mile for comparison). But, 703 wh/mile??!! That means less than 1/2 of my usual range will be available. Ugh.

    So my question is, in this kind of crummy weather, should I expect my range to be 50% of what it was in the summer? Will it get even worse when the temps drop to well below freezing?

    Or was this just a freak consumption reading?

    Anyone out there who has had their MS through last winter?
     
  2. elecblue

    elecblue Member

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    Having driven through last winter and seeing my mileage values, a reasonable approximation is 15%-20% reduction in range (i.e., more energy use).
     
  3. Vger

    Vger Active Member

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    Same observation here, when on a considerable road trip, where range really matters. I have often noticed that there seem to be big "start-up costs" on short trips, or at the beginnings of long ones.

    The worst losses in range we saw last winter were in 10-15ºF and blowing snow with adverse wind, and it took us 250 miles of range to do a 200 mile leg.
     
  4. Zythryn

    Zythryn MS 70D, MX 90D

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    Short trips are misleading in cold weather.
    When the battery is cold the battery management system will run to warm up the battery. This takes a lot of energy.

    It makes very short trips very energy intensive.
    Next time, take a look at the energy use after one mile, and then three, and so on. As you drive further the Wh/mile will continue to get better.
    That said, the energy use will increase in the winter. After driving last winter we found a range of 200-210 to be a good ballpark.
     
  5. cinergi

    cinergi Active Member

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    When it's closer to 0-15F, you'll see about a 20% hit on range for longer distance trips. For short trips like you described, you'll see enormous Wh/m readings because you're bringing the cabin up to temperature.
     
  6. Bifff67

    Bifff67 Member

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    7 miles is not enough to give you a useful number. You need to give that screen some more time. I think it updates every 5 miles. Get a long term average.

    I am in DC and last winter wasn't too cold so can't compare. But our summer was warm and I easily get 250 miles on the highway at the peaks of weather. I guess you will see much colder weather but I can't see 20% redux. Elon said in one of his interviews the heater was 6KW at worst peak. So that is 10% of a 60kwh pack and less of a 85 for an hour. And you won't draw that peak level full time except in brutal cold. Hope that helps. (of course the battery also has some reduction in real cold temps too, don't know how much. Charge it such that in the morning the charging just finished and the batt is still warm.)
     
  7. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    Also, heating the battery. An MS, cold soaked below 32˚ F. or lower, will consume 10 kW or so until the battery and cabin start warming up. The colder you are, the longer that very long-toothed, icy vampire sucks at 10 kW. :scared:

    Whenever possible, preheat on shore power. That means turning on the "CLimate," and charge some to warm up the battery. Put it in "Range" mode for 15-30 minutes. Because of the cabin and battery heating, there won't be many miles going in the battery; don't worry.
     
  8. Doug_G

    Doug_G Lead Moderator

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    Totally agree that short trips exaggerate the effect due to pack heating.

    I have personally seen a real-world range of over 330 km (206 mi) under truly horrible conditions - snowstorm and -20C (-4F) temperatures.
     
  9. jeffnorman

    jeffnorman Member

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    If I start the car up from the app to let it warm up before unplugging from the charger, could I avoid the 10Kw loss?
     
  10. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    A little bit of semantics, you can't "start" the car from the App, but you can turn on "Climate" and start a "Range" charge. The "Climate" will turn off after an hour, but the "Range" charge will keep going. Just don't leave the car charging for hours in "Range" mode too many times.
     
  11. Doug_G

    Doug_G Lead Moderator

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    If you turn on the cabin heat, it also turns on the pack heater. If the car is plugged in it draws that energy from AC.
     
  12. FreeOfPge

    FreeOfPge Member

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  13. FlasherZ

    FlasherZ Sig Model S + Sig Model X + Model 3 Resv

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    Too hard for me to give you apples-to-apples because I drove the car differently when I first got it, and my wife started driving it during the spring months. I recall having an average of ~400 Wh/mi during last winter, and now my average is at ~365 Wh/mi after 9 more months. So very roughly if you consider each qtr being 400/380/350/350, figure about 15% more in winter/colder weather. Of course, much of that was before 4.0 & its sleep mode, too.

    There was a giant thread about experience in much colder climates...
     
  14. David_Cary

    David_Cary Member

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    Just a point that might be obvious.

    If you drive 15 7-mile trips in a day, your range/energy use will be terrible. It is not so bad if you drive a single 105 drive. Just like an ICE. So depending on your driving habits the winter hit could be much greater than 20%. A warm garage in the morning probably helps a lot.

    I guess my point is that YMMV. If you drive 50 miles from a warm garage and then park in the sun and drive 50 miles home, your range loss will probably be less than 10%. If you drive 10 7 miles trips all from cold parking spots, your range loss will be greater than 20%. So comparing to someone else has to be done in context.
     
  15. sp4rk

    sp4rk Banned

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    Just FWIW, last night at 19 degrees, I left my car out all night, unplugged.
    Started with 175. Lost 5 miles. Better than I thought.
    As for driving ... mate of mine is driving from Sycamore to Madison today, see what he "loses" if anything.
     
  16. Argelius

    Argelius Member

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    I seem to remember reading somewhere that you can set the "charging scheduler" (or whatever it is called) so that the charging is completed shortly before you are ready to go in the morning, thereby "preheating" the battery.

    Is this correct and, if so, how do you schedule it to do so. (I haven't yet remembered to play with this function yet).
     
  17. kendallpb

    kendallpb Model S: P 8061

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    So, just turning on Climate won't kickstart battery warming? Bummer.

    Is there any need to range charge, for example, if you've lost some vampire overnight, can't you just start it charging? Or if, like me, your charge point is 80%...I could just start it charging standard via the app, right (since the app doesn't have %s, just the standard/range)?

    - - - Updated - - -

    Whoops, good point. In winter, it sounds like I should make my charging time later than I've been using, so it's ready just before I go--then the battery should be warmed up. But I'll still want to pre-warm the cabin.

    FYI to get to charge scheduling, tap the battery icon at the top near-left of the main screen; there's a button on that screen for scheduled charging. Off to change this now...the trick being, my hours are a little inconsistent, so I don't want to charge too late.
     
  18. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    Also, remember that charging will be a little slower because much of the charge power is going to heat at the start of the charge cycle. You could start a little early with scheduled charging to get to 80% an hour or so before you leave. The battery takes a while to cool off. Then 15 minutes or so before actual departure (with coffee), use the App to turn on Climate Control, and change the charging from "Standard" to "Range" and back to "Standard." The 80% charge will display in the App as "Standard", but when you go to "Range" and back, "Standard" becomes 90%.

    Enjoy!
     
  19. kendallpb

    kendallpb Model S: P 8061

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    Good point. I am charging to 80% anyway, so I could do that. I think I have to charging late enough but with enough of a window, but I'll keep that in mind, thanks.
     
  20. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    #20 Cottonwood, Nov 24, 2013
    Last edited: Nov 24, 2013
    Hypermiling in the Winter...Brrr

    Yesterday, I drove 228 miles with 2,000 feet elevation gain (12-14 equivalent miles, total 240 equivalent miles) in on a range charge of 255 miles in a P85, arriving with 13 miles left in the battery. The temperatures on the route ranged from 40˚ F. at the start to 12˚ F. on some passes, and probably averaged 26˚ F. or so.

    The route was from the 70 Amp J1772 in Pagosa Springs at 7,000 feet to the Supercharger in Silverthorne at 9,000 feet. (169 N 7th St, Pagosa Springs, CO 81147 to Silverthorne, CO - Google Maps) I had hoped that the 70 Amp J1772 would be installed in Salida for this trip, but the electrician was delayed and I needed to get back to Boulder. :crying:

    Range Consumers:
    1. Freezing Rain and Road Spray that Require the Defroster - Going over Poncha Pass, the temperatures dropped to 22˚ F., some freezing rain and/or road spray started icing up my windshield and obscuring my visibility, and forced me to go to full, high defrost, and turn off range mode to be able to see. In 10 miles, I lost about 4 miles of reserve range. :eek:
    2. Slush - Driving through slush is a real drag, literally. Going over Wolf Creek Pass there was a mixture of hard packed snow, wet roads, and slowly melting snow in between. I could feel the tires cutting through the slush. To minimize losses, I tried to keep the wheels on the hard pack or on the wet pavement. Even so, with the 45 mph speed limit over Wolf Creek, I am usually able to build several rated miles in the crossing. Yesterday, I lost a mile or two. Luckily, the lowest temps were about 27˚ F and I was able to rinse the spray and slush off of the windshield with the deicer, windshield fluid.
    3. Cold - Cold uses extra energy to keep the cabin and battery warm. I started just as a range charge ended, so the battery started warm. Also, during the range charge I turned on the climate control and set the temperature to 77˚ F. for about 40 minutes to store as much warmth in the cabin as possible. For the first 30 minutes of the trip, I was able to drive with the climate control off, and was comfortable with this stored heat. As the outside temps went down, I had to turn the heat on and off at its minimum 64˚ F. with the "blue, cool" defroster mode on to keep the moisture from my breath from fogging up the inside of the windshield. I wish the temp could be set to lower than 64˚ F. After the first half hour, I drove with my fleece, wool cap, and gloves on. The seat heaters are a good way to stay warm without using a lot of energy. I found that putting my fingers between my leg and the warm seat was a great way to warm cold fingers.
    4. Loss of Aerodynamics from Ice - See the picture below. I did not realize that I had this much ice in the wheel wells until I went over 60 mph on the descent off of Fremont Pass, the car (5.6) went into "Low" suspension mode, and the road pushed the suspension into compression. Boy, was that I surprise when the studded Hakas started grinding into the ice. I had no idea what was causing the horrible sound until I stopped and walked around the car. BTW, when over 50 mph, the car will not let you force it back to "standard" height with 5.6.

    Range Extenders
    1. Slow Down - I knew this trip was going to be a challenge. Depending on how I felt I was doing, I set my maximum speed somewhere between 50 and 55 mph. Only after crossing the last pass, Fremont, when I knew I had Silverthorne made, did I take the speed up to 65 and 70. It was great to drive at speed with the heater blasting. I would have arrived with closer to 20 in the battery without this extravagance.
    2. Tail Winds - The effect of tail winds can be huge. After the big loss of range over Poncha Pass, and with the temperatures dropping, I was about to pull into an RV park with 14-50's, but as the park came into sight, it has a U.S. Flag out front that showed I had a great tail wind my direction. The forecasts were for this wind to keep going over Fremont Pass, so I decided to push on. Between Leadville and Fremont Pass, it was pure joy to watch the cold snow, ground blizzard push snow down the road in front of me.
    3. Hypermiling - Gentle, energy efficient driving helps. Accelerate and decelerate gently; when possible plan ahead and feather the accelerator pedal to decelerate without using regen. Use cruise control whenever safe. Gently enter and leave cruise control by matching the accelerator pedal position to the cruise speed when turning cruise control on and off.
    4. High Altitude - Density altitude is not quite as high when the air is cold, but its still better than sea level. For the aerodynamic losses, I probably have at least a 15-20% advantage on this drive that averages 8,000 feet over doing the same drive at sea level.

    I did not know if I would be able to finish this drive on one charge, and there were at least two points where I was ready to stop and add a little to the battery. The fact that I knew of several places to charge along the way and was ready to do so if needed eliminated and range anxiety.

    Plan ahead and bundle up. Hopefully, the next time I do this drive, the 70 Amp J1772 will be in Salida and I can drive a little faster and stay warmer. :smile:

    Ice.JPG
     

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