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AAA FUD: Winter Driving Range

Discussion in 'Model 3' started by SageBrush, Feb 7, 2019.

  1. billh13850

    billh13850 Member

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    The most questionable part of the report is the implicit claim that these results are typical and relevant to users. That's where the falsehood lies. That is to say, it's not the report, it's the misleading headlines hawking it..
     
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  2. happyzod

    happyzod Member

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    Tesla is pretty good at getting the stated range if you drive ~70 MPH with no climate control. Once you turn on climate control, things change.

    Turning on heat, you can lose anywhere from 4-30 rated miles per hour. You lose less if you set the heat to the lowest number and reduce fanspeed to 1. You lose more at max fanspeed and high temps. If you had the heat at full blast, even driving 70mph on the long range battery, you would be getting 190 miles of range.
     
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  3. Darthbenji

    Darthbenji Member

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    #23 Darthbenji, Feb 8, 2019
    Last edited: Feb 8, 2019
    Basically there are a million different combinations of settings and drives that would result in a million different outcomes. It’s the same crap that used to happen to apple all the time: ‘New iPhone will break if dropped’.

    Here’s an article from the Toronto Star that details someone’s harrowing drive home from work and reduced range. Driving my Tesla in Toronto one winter night took a little strategy and a lot of shivering in the dark | The Star
    The headline should be ‘dummy almost runs out of charge after forgetting to charge his car at his virtual home gas station the night before’.

    “Foolishly I had neglected to charge the batteries at home the night before.”

    Author of his own misfortune, not Tesla

    I can’t imagine blaming Apple for a dropped call due to a dead battery when I forgot to charge it.
     
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  4. Rex Kramer

    Rex Kramer Member

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    AAA is an organization that has been around for a very long time, and as such, has strong ties to established auto manufacturers, oil companies, and dealership associations. I've been a member for a long time and to my recollection, the word "Tesla" has appeared only once in their monthly membership magazine.
     
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  5. adaptabl

    adaptabl Member

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    The report seems very fair and factual. Potential EV owners should be educated on how EV's operate in different conditions.
     
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  6. Darthbenji

    Darthbenji Member

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    Fair and reasonable would include a paragraph stating that results are only correct for their circumstances and that it’s pretty simple to mitigate them. They chose not to take part in the education process you agree should take place. They had a great chance to take part and chose to go with a negative slant instead.
     
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  7. SageBrush

    SageBrush 2018: Drain the Sewer

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    Yep. It would also be fair and reasonable to read the study method before commenting but that is too much for some people.
     
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  8. Darthbenji

    Darthbenji Member

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    I did read it!
     
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  9. SageBrush

    SageBrush 2018: Drain the Sewer

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    Clearly. My comment was not directed at you. Sorry for the misunderstanding.
     
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  10. dgpcolorado

    dgpcolorado high altitude member

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    Hmm, "EVs lose range in cold weather." In other news: "water is wet" and "fire is hot!"

    I wonder if AAA is aware that ICE cars also have reduced range in winter? Yes, it doesn't matter as much because there is a gas station on every corner and they are so inefficient that they generate huge amounts of waste heat for climate control but, still...
     
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  11. MentalNomad

    MentalNomad Member

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    That's my situation. I have an assigned space in a parking garage that is exposed to outdoor temps. During the recent cold snap, my range was severely reduced.

    (I have the use of a shared on-site charger, but can't leave my car parked there all the time.)

    I find it highly relevant.

    I don't see a negative slant. The title is impartial:

    "AAA ELECTRIC VEHICLE RANGE TESTING AAA proprietary research into the effect of ambient temperature and HVAC use on driving range and MPGe"

    The finding are, to me, of interest:

    "In isolation, hot and cold ambient temperatures resulted in modest reductions... an ambient temperature of 20°F resulted in a 12 percent decrease"

    "HVAC use results in significant reductions... HVAC use at 20°F resulted in a 41 percent decrease"

    During the latest cold snap - where I saw temps of 20 and below for several days - I saw a > 40% decrease in range. (I drove 70 actual miles over a number of small trips to see 150 miles come off the estimated range.)

    I was aware that some people "home charge" and could time charging to end near their daily departure time, such that the battery isn't so cold when they head out. I thought this would make a huge difference... but now I see that this could reduce the 12% loss due to a cold battery, but that might not do much against the larger impact of using the heat. Pre-heating the interior while plugged in might reduce the power consumed while later driving, but it's still consuming electricity to produce heat. A heated garage would help, but again, heating a garage also consumes energy.

    It's all worth knowing - and doesn't strike me as slanted, at all. This makes no change in that I still love my Model 3, but if I'd known this earlier, I would not have been so surprised when my range decreased with the cold weather and I wouldn't have "spun my wheels" trying to learn if this is normal, or if there was cause for concern!
     
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  12. gnuarm

    gnuarm Member

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    When they talk about dressing warm, what exactly does that mean?

    Cold Water Safety

    This is the sort of dressing for the cold that I am used to.

    If you really want to read a horror story, check out Case 7 at the bottom of the page. Those were able bodied Marines 100 yards from shore. No one made it to shore.

    I'm pretty sure I'm not going to die at the wheel because of the heater, but sometimes I'm not sure. The cabin literally never gets warm and I can see nearly no impact on my mileage display regardless of the heater setting. So maybe my heater just isn't working well and that's why it doesn't show up on the mileage.

    Here's a Tesla question: If the volume and the heater fan speed both go to 11, why does the following distance in the cruise control only go to 7?
     
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  13. ricohman

    ricohman Member

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    Where I am you dress to survive. Some roads are not traveled for a day or two.
    It's -52 again tonight. With jeans and even a "winter coat" you would die if your vehicle had no more heat to offer.
    I will run the heat full blast if I want. And plan my trips around whatever mileage is left.
    I accept the fact that there will be 4+ months when an EV is not practical.
     
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  14. gnuarm

    gnuarm Member

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    I think these sorts of responses to valid reports are not very useful. Your first paragraph diminishes the report as being obvious even though the issue is not that range dropped, but the extent of the drop. Your second paragraph tries to make the report invalid by implying that this is not unique to EVs, even though the extent of range loss is not even close to comparable.

    My experience with cold weather range loss is that it can be very significant impacting every trip I've taken in cold so instead of charging every 200 to 250 miles, I have to charge at nearly every charger and not just for 20 minutes. I spent a day traveling 500 miles from Tennessee to the South Carolina beach a few weeks ago. Literally a day! We left around 10 in the morning and didn't arrive until about 12 hours later. Part of the problem was spending too much time trying to charge within the last 10% to be able to skip a charger which didn't happen anyway, but still, stopping at every charger on a route has a significant cost in time on a trip. It's much quicker over all if you can just stop for meals and use that time to put a large charge on to fully utilize your range. The meal stop is mandatory in my car, but on this trip we had to stop for a meal twice along with all the shorter charges.

    My friend drives this trip in her hybrid SUV in about 8 hours with one stop for fuel, but then no meal stops really, so call it 9 hours with a meal.

    I guess my point is that the numbers are how a report has to analyze the range impact of the cold. But that also needs to be reflected off the spacing of chargers to find the total inconvenience impact on trips. Short trips around town the impact is minimal. On road trips not so minimal at all.
     
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  15. gnuarm

    gnuarm Member

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    In spite of the range issues in the winter, Consumer Reports announced the Tesla model 3 has the highest consumer satisfaction of any car. So go figure! I guess they are so amazed by everything else in the car they don't notice their teeth chattering. lol
     
  16. RDoc

    RDoc S85D

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    For us, and most people, apart from maybe urban Uber drivers and people without home charging, the only time range is an issue is during sustained highway driving. Given that, the only test cycle I'm interested in is the HWFET, particularly the second one in each set of tests, after the car has run for a long time at 65 mph (CSC). Unfortunately, they don't say how long the CSC is for each car or how soon they start the next set of tests. They do run the 23 minute UDDS urban cycle before the second HWFET so the car cools off after the CSC which isn't at all realistic. The highway test is only 12.75 minutes total which isn't enough to warm up the car. A far better range test would be to just run the car at speed, HVAC on or off, until it stabilized, then run the test, but they didn't do that.

    For the non-HVAC tests, the HWFET1 and HWFET2 consumption at each temperature is about the same, 20F is about 6-7% more than at 75F both times. This is a bit surprising to me, because I'd expect the second test to be significantly better than the first after the long CSC run warmed up the car. Maybe the urban UDDS cycle did the trick, but who knows, the tests certainly don't control for it.

    However, for the HVAC test, it's quite surprising. Unfortunately, they also don't say if they ran the HVAC during the middle CSC, but just using the numbers for HWFET1 and HWFET2 with AC on, it's pretty odd. HWFET1 HVAC on is 44% higher than HVAC off, but HWFET2 HVAC on is only 30% higher. That means that the 23 minute urban driving cycle somehow didn't warm up the car's interior the first time. Since the consumption, HVAC off, was about the same both the first and second time, why was the HVAC consumption so much higher the first time? Weird, and completely unexplained.

    At a minimum, I'd say, for highway driving, the HVAC at 20F uses 30% more than at 75F, rather than their 37%. But I'd like to see a test that really got the car into equilibrium. Both seem very high compared to my experience.

    Overall, my conclusion is that these tests were poorly designed to produce relevant, as opposed to accurate, information.
     
  17. Electroman

    Electroman Well-Known Member

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    I can show a 80% loss if I drive 5 miles and cold soak it for a few days at -20F, and then repeat it for two or three more cycles. It is factual but does not reflect the situation where range is really needed.
     
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  18. Electroman

    Electroman Well-Known Member

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    #38 Electroman, Feb 9, 2019
    Last edited: Feb 9, 2019
    x.jpg This was my yesterday's 35 mile office commute around 6:30 am when the temps were at 26F and no wind. I started at 231 miles and ended up at 191. Speed was mostly 70 mph and 75 for some small stretches, flat terrain

    40 miles consumed for 35 mile of driving, which is 15% loss. Efficiency 269 wh/mile, and if you use that, it is around 16% loss

    But I have seen consumption as high as 25 to 30% on the same stretch with some headwind. The point here is you always need to provide context and data points for multiple scenarios, unless the intent is to scare people.
     
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  19. MentalNomad

    MentalNomad Member

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    Headwinds don't vary in the dynamometer.
     
  20. dsnows

    dsnows Member

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    I recently completed a 300 mi. trip with the temperature 2* F. when starting. I charged for an hour just before leaving to pre-heat the battery. I preheated to cabin so we didn't need to use as much heat when driving, kept temp on 68* enroute. Used range mode. I calculate I lost about 10-15% range on a mix of highway and secondary roads.
     
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