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I understand "Rated Range" but PLEASE explain this to me

Discussion in 'Model S' started by themacs, Jan 2, 2016.

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  1. themacs

    themacs Member

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    Some answers and QUESTIONS:

    On Power Management: Should energy savings be ON or OFF?

    On Climate: Should Smart Reconditioning be ON or OFF?

    On Efficiency: Should Range Mode (i) be ON or OFF?

    On Efficiency: Regenerative Braking SHOULD be on Standard NOT Low, correct?

    The car has 1000 miles on it with 21" tires

    The climate control was on 78 the whole trip.

    No braking for the trip, no wind and mostly flat driving. Also we went up and back so whatever we went slightly up we came down ( I realize you don't get it all back though).
     
  2. Xenoilphobe

    Xenoilphobe Active Member

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    Pano Roof Open or windows open at speed also create more drag and increase the watts per mile calculation
     
  3. themacs

    themacs Member

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    You make a lot of sense. As I look back it as closer to 50 degrees out. We are on the water and it is not as cold as inland though. We DID have the heater on AND there was more "use of miles" going rather then returning.

    I had no idea that the heater was the most milage killing part of the Tesla.

    No Ludicrous mode on the car. Just insane mode of course. I thought $143,000 was enough rather then adding $10,000 more!!!!!!!!!!!!!!!!!!



     
  4. green1

    green1 Active Member

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    Many ICE cars allow you to see calculations based on your past averages, Tesla currently lets you choose between "ideal" (read impossible to obtain) and "rated" (read very difficult to obtain) There's no reason they couldn't also add "average" (read what you actually have been getting in the past) it would be easy to add and would give people a lot more confidence in what's going on. For that matter, I really think they should nuke the "ideal" option all together, it's a completely made up number that isn't from any test, or any reasonable expectation that anyone can actually get.
     
  5. ChadS

    ChadS Last tank of gas: March 2009. EV miles: 254,000

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    #45 ChadS, Jan 3, 2016
    Last edited: Jan 3, 2016
    I am going to adjust my answer for some new information: 21" tires, and heater set at 78 on a 50 day. If we add 3% for the tires, and adjust the HVAC factor to 10%, then from the numbers in the thread I linked to, we should expect you to have used

    168 * 1.33 = 223 + 5 = 228. You actually used 231, so that's pretty darn close to the expected energy consumption.

    Rated miles are exactly the same thing as EPA rated MPG - a reasonable tool for comparing across cars, but completely useless for determining how much energy you will use on a specific trip. The battery doesn't store miles, so displaying rated miles can be pretty misleading (in fact the only BLOG I have written here asked manufacturers to not do that). That's why I follow MSEV's advice and just display the percentage of the battery remaining. Most days it doesn't matter because I know I'm not going to drive anywhere near the battery's limits, so I don't even look at it.

    The few days a year I am on a road trip, I watch the Trip tab of the Energy app - a very easy-to-follow graphic depiction of how much battery you have, need to get to your destination (well, that part is an estimate; it takes in to consideration some things like elevation, but not others like head winds), and are using. If you started with a big enough buffer, you have no worries and the screen shows you that. If it starts to get tight, just slow down. If you find yourself having to slow down more often, you will probably start leaving with a larger buffer. I tend to leave with a good-sized buffer so I never have to slow down.

    - - - Updated - - -

    That doesn't matter for driving; it's for when the car is turned off. I leave energy savings ON; it can save a few miles (especially when cold) if the car is sitting there for a while, and doesn't cost you anything other than occasionally a few-second delay when you, say, try to connect to the car with your phone.

    Smart Preconditioning should be OFF if you have a variable schedule - it tries to watch what you do and then do it automatically for you. But if you take off at 7am every day and set the temperature to 78 degrees, it can be good in that the car will be warm before you start. This also means you used grid energy to warm the car, and can start your trip with a full battery so you can go farther. However, it doesn't decrease total energy used, and if it's just a short round-trip to work it doesn't really matter whether it was from the grid or from the battery. It only matters on a long trip, but unless you take long trips very regularly it's not going to learn the pattern.

    Pre-warming manually before a trip is a very good idea (mentioned upthread).

    On.

    It depends on how you drive. If you use regen to replace some or all of the braking you would otherwise HAVE to do, regen is a good thing - it recovers some energy that would otherwise be wasted heating brake pads, so STANDARD is what you want. But if you lift your foot off the accelerator while driving and it slows the car down and then you have to speed up again - that's wasting energy, so LOW would be a better setting.

    I leave mine on STANDARD and try to only use regen to replace braking I have to do.
     
  6. S4WRXTTCS

    S4WRXTTCS Active Member

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    #46 S4WRXTTCS, Jan 3, 2016
    Last edited: Jan 3, 2016
    Exactly. I don't really have a problem with the Rated miles setting. What I said was mostly meant as a joke on the dichotomy of a Tesla MS.

    One of the fastest sedans you can buy; drive it in the right hand lane going 60
    Safest Car on the Road; insurance replaces the entire car if someone touches it wrong
    Lands on Consumers Reports top 10 list twice; Not recommended by consumer reports because of poor reliability history
    Not ideal for road trips; best damn road trip car on the market.
    Made in California and leaves a lot to be desired in Cold Weather; Sells like hotcakes in Norway
    Software upgradability is a huge selling point; Has to deal with customers who won't upgrade because they went Jonathan Ive on the UI.

    But, in all seriousness: What I'd like to see is the Ideal Range removed, and replaced with an Average over X miles setting. Now I get that there is already an Average of X miles display in the energy meter app, but it would be nice to replace the IC range with that one.

    I do think it's useful to have the EPA rated range since that gives me a target to try to hit. So I know if I'm not hitting it at the expected speed/temp that something is up (headwind, tires, etc).

    I have absolutely no idea what the ideal range setting is useful for.
     
  7. dgpcolorado

    dgpcolorado high altitude member

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    This is something that newcomers to EVs have to learn. In an ICE car most of the fuel is wasted as heat and some of that heat can be tapped for "free" cabin heat. In a BEV all of the cabin heat must come from the battery pack and it can represent a significant portion of the charge/range, as you've discovered.

    As others have mentioned above, there are several things you can do to mitigate the range loss due to heating: One is to preheat the car while plugged-in before leaving on a trip, thus using shore power rather than battery for the initial heating (and it is nice to get into a warm car, especially for those of us in snow country). Another is to use heated steering wheel and seats, if you have them, because the amount of energy they use is trivial compared to the cabin heater. Warm hands from a heated steering wheel can add a lot to comfort even in a cool car.
     
  8. S4WRXTTCS

    S4WRXTTCS Active Member

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    What's with the use of "Shore Power"?

    Is this a boat?

    I thought this was a Spaceship. :p
     
  9. jerry33

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

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    1) Doesn't affect driving, only vampire drain when parked and not actively charging.

    2) Doesn't affect driving. It's supposed to figure out when your trips start and preheat/precool the cabin. Doesn't work very well right now.

    3) Range mode off when charging on when driving. Note that this mainly affects short trips, not long trips.

    4) Regen standard aways.

    5) 21" tires reduce range.

    6) 78 seems somewhat high, but if you preheated the cabin, maintaining heat doesn't cost that much.

    7) You didn't ask, but if you have the charge timed to stop just before you start driving, that will save a bunch of energy which would otherwise be required to bring the pack up to operating temperature.

    - - - Updated - - -

    Ideal range is useful for checking the state of the battery because they mess with the algorithm less than they do with rated range.

    - - - Updated - - -

    Heat is number two. Aerodynamic resistance at high speed in number one.
     
  10. themacs

    themacs Member

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    7) You didn't ask, but if you have the charge timed to stop just before you start driving, that will save a bunch of energy which would otherwise be required to bring the pack up to operating temperature.

    Thanks, that is very helpful. I got up and unplugged the car in the garage and it sat for about 1/2 hour before we left. I'm sure it had to "heat up" again which wasted power.

    Great Forum. Always learn something!
     
  11. dmckinstry

    dmckinstry Model S - U.S. P - #1649

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    Unless the outside temperature is quite high, the heater causes much higher consumption that the air conditioner.

    In the winter months, I typically just use the seat heaters. At 58k miles my lifetime average is 293 Wh/mi. It would be much lower than that if it weren't for long road trips. i.e., round trips of 2800 miles to 4000 miles.
     
  12. dgpcolorado

    dgpcolorado high altitude member

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    :) Actually "shore power" is a pretty good analogy for what's going on, and I'm not the first to use it. I suppose I should have said "grid power"...
     
  13. andrewket

    andrewket Well-Known Member

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    It says torque is optimized when range mode is on; it doesn't say torque sleep is inactive when range mode is off.

    Unless something changed, torque sleep is always active. It's impact is increased when range mode is on. I got this from an inside source at Tesla, but it was 10 months ago. I suppose this could have changed.

    I believe torque sleep was also enabled for single motor cars a few months ago. Go figure that one out.
     
  14. stopcrazypp

    stopcrazypp Well-Known Member

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    Release notes make it clear what it does:
    "Torque Sleep technology developed for Dual-Motor Model S as now been activated in Rear-Wheel Drive Model S. When at a standstill, the motor will now completely de-energize and seamlessly re-energize when needed. Torque sleep and wake-up saves energy and is so fast it's imperceptible".
    Basically it cuts all power (meaning absolute zero) to the motor when at standstill, while I presume previously it didn't (there is still probably some standby power consumption via current through the motor windings). This would also help in the boundary of regen and power (going down a slight grade) where it makes sense to cut all power.
     
  15. DCGOO

    DCGOO Active Member

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    It is borrowed from the RV industry, shore power vs house or coach power.
     
  16. ecarfan

    ecarfan Well-Known Member

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    "Heater set at 78 on a 50 degree day". Suggestion: set heat at 72 and wear something warm in the car. Everyone is different, but I would roast with the heat set at 78 no matter what the outside temperature (and yes I have been in sub-freezing temps for days in my S even though I live near San Francisco).
    But in reality setting the cabin temp in the high 70's makes a minimal amount of difference as to how much range you get. Main things are speed, headwinds, rain/snow, temperature, elevation increase. Other things are minor.
     
  17. brec

    brec Member

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    Why off when charging?
     
  18. jerry33

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

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    Also note that the seat heaters use almost no energy compared to the cabin heater.
     
  19. andrewket

    andrewket Well-Known Member

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    I was being a bit sarcastic (it didn't come through, I realize.) It's not intuitive that a single motor S could benefit from torque sleep - but yet it can as demonstrated with the text you provided from the release notes. A dual motor S can benefit from the same thing, and it's my position that range mode does not need to be on for torque sleep to be active. Range mode may increase the benefit, but it's not binary.
     
  20. austinEV

    austinEV Supporting Member

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    I was recently road tripping at high speed, low temp with a headwind. The headwind was the deciding factor, I had made this route a million times. I was dismayed at my energy consumption which was projecting a thin safety margin to my next SC, so I ducked in behind a semi in the right lane and just chilled out and drafted for an hour. As long as I have a solution I dont worry too much about the kwh/mile.
     

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