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Tesla Cross-Country Trip

Discussion in 'Supercharging & Charging Infrastructure' started by airj1012, Jan 30, 2014.

  1. brianman

    brianman Burrito Founder

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    Indeed, but "parasitic" isn't exactly the word I'd use for the driver or battery protection and comfort (climate control).
     
  2. stevezzzz

    stevezzzz R;SigS;P85D;SigX;S90D;XP100D;3LR

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    Right. But in my experience, normal driving at highway speed is enough to keep the pack warm in cold temperatures: it's starting out with a cold-soaked pack that costs you range, big-time. For instance, last night I drove a 90-mile round trip in sub-zero temperatures. By charging just before I headed out from my unheated garage, I avoided the "Battery is warming" message entirely. My consumption was still about 20% higher than nominal, but hey, I wasn't about to leave the heat off when it was -9º F. :biggrin:

    - - - Updated - - -

    Noted and agreed. But "Non-motion-inducing" is so stilted. :wink:
     
  3. scaesare

    scaesare Well-Known Member

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    I've used "non-locomotive"... still doesn't roll off the tongue, but does save a syllable and a word. :)
     
  4. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    Yes, and a significant by-product of preheating the cabin (turn on climate control with the app) is that it also warms the battery. Even in a 50˚F. garage, I have found that doing 2-4 preheat cycles (1-2 hours, turn back on every 30 minutes) is what it takes to fully warm the battery pack for long distance winter driving. This all applies to preheating on shore power.
     
  5. J in MN

    J in MN S60 P12635

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    #245 J in MN, Feb 7, 2014
    Last edited: Feb 7, 2014
    Can you be more precise?

    My experience is that heating the cabin with range mode off, either on- or off shore power, will only heat the battery to the point where regen is zero, but without the regen disabled message (presumably zero degrees Celsius).

    In a 50 degF garage there is not much if any battery warming required.

    And, to stevezzzz's question, at -30 degC and < 90 km/h, the motor and inverter cannot even keep themselves warm, let alone the battery. Even at -20 degC and 100 km/h it takes more than 30 minutes to go from zero regen to 30 kW regen.
     
  6. stevezzzz

    stevezzzz R;SigS;P85D;SigX;S90D;XP100D;3LR

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    My comments concerned only the "Battery heating" message; I had only partial regen during most of the drive. The other thing to remember is that with all that thermal mass, a warm battery will stay above ambient for a very long time. The car sat out, unplugged, in the middle of my 90 mile round trip for over three hours, in temperatures from 0º to -9º F., and I still had a little regen and no "Battery heating" warning when I started home on the last leg.
     
  7. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    #247 Cottonwood, Feb 7, 2014
    Last edited: Feb 7, 2014
    Here is an example from a couple of months ago:

    When I started with cabin temps in the low 60˚'s in a 50˚F. garage, at end of taper on a range charge, I got the power used in the curve below. This curve comes from a TED 5000 measuring power into the HPWC only. The cabin temp was set to the high 70˚'s and went to the high 80˚'s, and the air conditioner did not turn on. The lower segments of the curve below are the power drawn to do the taper on the range charge without heat. The upper, ragged segments are with the preheat on. I assume the the extra power used when the climate in "on" is power to heat the battery pack. The cabin was warm, and the air conditioner did not turn on. I further assume that the reason that the cabin went into the 80's was waste heat from the charging and battery heating. As a result of these extra shore power heat cycles, I was able to drive for 45 minutes or so in 20˚ outside temps before the cabin dropped to 65˚ with the climate control off. Also, on this trip, I noticed no extra power draw for battery heating during the drive from Paogsa to Boulder. I did stop at the 70A J1772 in Salida and the Supercharger in Silverthorne on this trip.

    The big point of all of this is that (as measured by power drawn by the MS), the car will draw power for considerable periods of time (over 2 hours here) to continue heating the battery pack from shore power. I consider this to be extra energy stored in the car before a long drive in the form of thermal energy stored in the thermal mass of the interior of the car and the battery pack. Doing this preheating on shore power before a long winter drive can make a very noticeable difference in winter range.

    Range Charge Complete w heat.png
     
  8. J in MN

    J in MN S60 P12635

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    So, did you restart the cabin heating every 20 minutes or so from the the phone app, or VisibleTesla, or something similar? Or are you saying it stayed on by itself for over 2 hours?

    I have never seen the battery heater turn on when it's above freezing in my garage. In fact, based on the diagnostic screen picture, and on my own observation, it appears that the battery heater only operates below 10 deg C battery temperature.

    It is known that repeatedly turning on the HVAC from the phone app will increase the cabin temperature to well above the set point. This has been discussed elsewhere on TMC before, and I am aware of another owner in Minneapolis who took his car to the service center to diagnose this "issue".

    The battery heater draws 3 kW, while the cabin heater draws 0 to 4 kW in range/eco mode, and 0 to 8 kW in normal mode. The steps in your chart appear closer to 4 kW than 3 kW to my eye.
     
  9. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    The power steps were about 5 kW at the beginning and dropped to 3 kW at the end. Yes, I continued to turn the "climate" on with the phone app. My assumption is that a side effect of the battery pack heating is the excess cabin heating, but that could be wrong. What I do know is that doing the charge just before I left with multiple "climate" cycles gave me an energy usage that was only slightly worse than a more moderate temperature day. I am sure that this used more energy total, but that excess was from shore power, and it did reduce the time needed to charge at the 70A J1772 to make it comfortably to the Supercharger.
     
  10. Doug_G

    Doug_G Lead Moderator

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    One nit with their blog Cross Country Rally: Day One | Blog | Tesla Motors:

    This is silly and unfortunate as it perpetuates the myth that this matters in the slightest. Driving at highway speed takes at least 20,000 watts. Playing the radio is probably going to cost you 20 watts. It'll reduce your range maybe 100 feet.

    In fact, there's no reason to concern yourself with ANY electric consumption other than HVAC and drivetrain (= speed). Turn on everything you want and drop your speed 1 mph, and you'll end up ahead of the game.
     
  11. JRP3

    JRP3 Hyperactive Member

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    Yes, I had the exact same feeling when I read that, sends the wrong message and is completely pointless.
     
  12. bluetinc

    bluetinc Member

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    But, I think that 20W for the stereo is fairly optimistic. I think that a usage of about 100W is probably much more on target. That would mean that over a 3 hour drive, the difference is about a mile. For "us" everyday that is meaning less, but if like them you are attempting to make a record and your target arrival goal is already almost 10 miles below 0, that extra mile might count.

    Peter
     
  13. anticitizen13.7

    anticitizen13.7 Not posting at TMC after 9/17/2018

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    Just my idle curiosity, but does anyone know the configuration of the two Model Ses used for the cross country run?

    From the photos, they look like P85 w' 19" Cyclone wheels, but I wonder what other options are installed.
     
  14. stevezzzz

    stevezzzz R;SigS;P85D;SigX;S90D;XP100D;3LR

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  15. FANGO

    FANGO Active Member

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    I'm getting to this late, but optimal speed is more like 20-25mph. Model S Efficiency and Range | Blog | Tesla Motors

    Full breakdown of why here for roadster Roadster Efficiency and Range | Blog | Tesla Motors

    You're right about the rest of course, hvac and speed are realistically the only things that matter.
     
  16. wycolo

    wycolo Active Member

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    > I think that a usage of about 100W is probably much more on target. [bluetinc]

    What, running subs to ward off the halt/lame/blind/crack-smoked? :smile:
    --
     

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