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how i reduce my cold weather long distance range anxiety

Discussion in 'Model S: Battery & Charging' started by balefire, Dec 28, 2013.

  1. balefire

    balefire Member

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    I recently did a number of long distance cold weather Chicago to Indy 200 mile trips in our S85.

    Just wanted to share a few things I did to decrease my range anxiety in the cold for long distance in addition to the normal recs:

    normal recs:
    1) max range
    2) range mode heater
    3) preheat
    4) time charge to end at trip departure
    5) check tire pressures
    6) cruise control
    7) go slow

    my recs:
    everyone's long distance trip is different and all the planning in the world often fails to completely account for everything. so what I've done is essentially, "freeze in the slow lane"** during the first 1/4 to 1/2 trip.
    1) minimal to no heater even on range mode
    2) 55 to 60 mph in the slow lane
    after analyzing my projected range (rated range is inaccurate) after the the first 1/4 to 1/2 trip,
    a) If I have 15 mile buffer, I will turn the heater on.
    b) If I have a 25 mile buffer, I will speed up to 65 mph or more
    c) If the buffer drops below 25 miles, I slow down
    d) If the buffer drops below 15 miles, I turn off the heater

    with this method, I've always arrived with a non anxiety inducing 15 mile range buffer, but my family was chilled for parts of the trip.
    anyone else this crazy?

    **
    http://www.greencarreports.com/news/1089040_life-with-tesla-model-s-east-coast-road-trip-freeze-in-slow-lane-or-languish-at-nissan-dealers
     
  2. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

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    I've always just made more frequent stops.
     
  3. balefire

    balefire Member

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    Waiting 1 hour for a 20 mile gain is not very productive or efficient to me at a traditional charge location.
    Further, other than Nissan dealerships, there are very few charging locations along the I-65 corridor between Chicago and Indy.
    Worse, on Sundays for our usual weekend return trip, these Nissan dealerships are closed.
    A supercharger in Lafayette, IN will hopefully allow me to never worry about this again.

    Until that time, my family and I will continue to freeze in the slow lane as David Nolan put it to maximize my efficiency on these cold long trips.
     
  4. Zythryn

    Zythryn MS 70D, MX 90D

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    I've heard that range mode can actually hurt. The battery is warmed more slowly in range mode leading to more time driving with a cold battery.
    I have not tested this as I just heard this recently.
    However, it does appear the battery warms up more slowly. I need to test if the lower efficiency of the cold battery outweighs the higher HVAC usage.
     
  5. balefire

    balefire Member

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    Does anyone know if in range mode the heater while on "shore power plugged in" is in range mode as well?
    I've thought about putting in range mode after preheating the car...

    Also, on some of my long trips in the cold, I've seen that the battery regen limit never goes away which I assume means the battery is never fully warm
     
  6. Doug_G

    Doug_G Lead Moderator

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    Yes in extreme cold, even on the highway the battery never warms to normal operating temperatures.

    I think it would be more comfortable to drive a little slower and turn the heat on in Range mode, as long as you can safely drive slower. Just a few mph should do it.

    Even more effectively, draft a truck. You don't have to get super close - 2 seconds behind will make a significant difference. If you are comfortable driving 1 second behind you can go 10 mph faster at the same energy consumption. The difference is probably greater in winter.
     
  7. yobigd20

    yobigd20 Well-Known Member

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    this makes a huge difference. I've watched my Wh/mi drop as low as ~180 going 60+mph when drafting big greyhound buses.
     
  8. jayhawk

    jayhawk Member

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    What is the lowest temperature you made the trip in? I go to Milwaukee quite often, and it is about 160 miles round trip. I drive about 70 MPH with heat, and had 50 miles of extra range in 35F weather, but was curious how low the temp can get before I need to change my driving habits.

    Also, once the supercharger station is up in West Lafayette, IN, you won't have any issues. Can just stop for a few minutes.
     
  9. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

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    I've tried both ways, and just leaving it in range mode and preheating from shore power works just fine. However, the coldest it's been has been -5C (My car is parked outside.) I don't know whether there would be a difference in behaviour at -25.
     
  10. Raven

    Raven Member

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    #10 Raven, Dec 28, 2013
    Last edited: Dec 28, 2013
    How about this....after doing 1-7 that you listed, do some basic math.

    Take your battery size, divide by miles required, then X 1000. E.g., for a 185 mile trip with 15 mile buffer... (85kwh/200mi) X 1000 = 425wh/mi.

    Now zero out your trip meter and make sure to keep average usage under 425. If wh/mi increases above 425, slow down. I've found speed is the most critical. All the rest is negligible. I think doing it that way really simplifies things since you don't spend nearly as much time watching the energy page and doing the math. Of course this is assuming a new battery at total capacity.

    - - - Updated - - -

    I hope you have the paint armor.
     
  11. Mario Kadastik

    Mario Kadastik Active Member

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    tesla-accu.jpg

    You cannot use 85kWh. From what I know the 100% -> 0 miles range is 76 kWh. If you stretch it all the way to bricking protection you can add another 4kWh to 80kWh, but that's it. So I'd recommend using 75kWh as the max capacity and ignore your planned reserve (that comes from the reserve in the battery or keep a small one). But yes, if you use that number instead of the 85kWh, then the methodology is the same. So going 200 miles on 75kWh means 375 Wh/mile. If your trip meter is averaging below that, then you're good. If you however know that you have some hilly driving ahead you might want to keep the average even further below that.
     
  12. wormhole

    wormhole Banned

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    Is this documented anywhere? I've never seen anyone suggest that so little of the battery is actually available for range or normal driving. I've seen the 81.1, but not the 75.9 for range mode. I'm very surprised that in advertising a 85kwh battery, TM actually reserves more than 10% of that capacity from 'view', not sure that's the best term.

    If 76kwh is really the range charge, then to get the EPA rated 265 miles, one must average 286 wh/mile just to get rated range...is this correct? I thought it was 308 (which is what the dotted line looks to be at on the energy app), which is the 81+kwh of actual available battery capacity available to the driver....sorry if this hijacks the thread
     
  13. Mario Kadastik

    Mario Kadastik Active Member

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    I think it is the 81kWh, but the estimated remaining range shows for the 75.9kWh probably and does some black magic to get to 0 at that point while you CAN actually keep driving after 0 for another ~5.1kWh. The easiest is for someone to do the risky test and charge the car to 100% and drive until it changes to Zero Miles and look at the kWh spent. If it's 75.9, then it's accurate here.
     
  14. wormhole

    wormhole Banned

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    Let me know how that goes :)
     
  15. 772

    772 Member

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    The way EPA calculates their rating is by driving the cars until they won't go anymore, so they ignore the "charge now" and used the 81.1 kWh. It's similar to the reserve warning you get in a ICE... you can still keep driving it but you have to refuel soon. In an EV, doing this is not good for the battery, of course.
     
  16. wycolo

    wycolo Active Member

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    THERMAL BOOTs

    Even on a sunny day wear these while in the car!! Also sweats underneath your jeans. This effectively removes any 'below seat level issues' from the trip equation.

    You can switch to your Manolo-Blahniks when you arrive at the Mall. :smile:
    --
     
  17. Raven

    Raven Member

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    Not a hijack at all. This is good info that I honestly wasn't aware of. I thought it was 85kwh available with bricking protection in addition to that. Had I not learned this, my calculations could have left me short.
     
  18. rjcbox

    rjcbox Member

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    Another good reason for Model S to have Adaptive Cruise Control
     
  19. arremgee

    arremgee Member

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    I haven't noticed much change until about 20*F. The biggest issues I've had are when it gets down into the single digits and negative numbers and then you'll start to see more drop and issues with the HVAC taking your energy and the battery having trouble getting warm.
     
  20. ThosEM

    ThosEM Space Weatherman

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    Where is this documented?

    Mario, please help us out here if you can. The figure you posted used to be located in a thread here on battery considerations, which were worked out by someone who did the homework needed to firm up the numbers. Can you find it now? I've been unable to do so, and even had trouble finding this thread because of issues with the forum software and Safari browser.

    BTW, I think the "do a little math" recommendation is a big service to us all. I'm tired of watching the energy app all the time, and that really seems like it will help when I do some longer distance driving...

    Any pointers would be much appreciated!

     

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