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Learning to love "Rated" miles

Discussion in 'Model S: User Interface' started by pilotSteve, Jan 20, 2013.

  1. pilotSteve

    pilotSteve Member

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    #1 pilotSteve, Jan 20, 2013
    Last edited: Jan 20, 2013
    Just completed a 350 mile weekend round trip from Portland to central Oregon (Bend). Route is along US26 up the side of Mount Hood (lots of elevation to climb then descend). Weather was clear and nice but cold (high of 40°, low of 21° I would say average was 35°). Two people and weekend bags going over from Portland, then four people and lots of suitcases (both trunks were completely full).

    I know this isn't breaking new ground for many of you but this was my first long range trip in cold weather, with my 21" summer tires as well.

    What did I learn?

    (a) on the Energy app, it works best for me to select 30 miles and Average (not instant). Why: because the up hill excess consumption and downhill regeneration smooth out the miles remaining display so passengers (maybe even the driver!) don't freak out at the over- and under- estimated miles to empty.

    (b) from my around-town experiences I discount about 20% off the Rated miles full (range) charge miles due to battery pack heating and cabin heat. Temp at 71° and two seat heaters on #1, also running the fan on #3 or #4 to keep the windows from fogging. So my initial 'guestimate' was the 264 mile Rated really would only be about 220 miles usable. Wanted to have at least 10% reserve so a 200 mile trip should be possible.

    (c) On the way over averaged 395 Wh/mi over the 170 miles driven, on return it was 355 Wh/mi same distance.

    (d) watching the energy app Average line (comparing to the energy budget) I knew that to achieve the Rated miles I could target driving a bit slower or at least less aggressive on the accelerator to get my average down close to the budget.

    (e) Ended the trip over with 30 rated miles showing (so that is about 15 less than my 'guesstimate') and the trip back with 49 showing (about 5 more than guesstimate.

    (f) yes cruise control really does lower energy consumption even going up/down hills. You can see how much less jagged the energy line is after 10-20 miles of cruise driving.

    So I am learning to trust my mental math and to reasonably assure my spouse we won't run out of miles just because the Instant display says we have only 20 mile remaining yet we have 80 miles to go!

    In short, I am becoming a believer in Rated miles provided you discount for environment (heat/cold) and make reasonable attempts to reduce acceleration and/or speed to get you 30-mile Average energy close to the Rated line.
     
  2. Doug_G

    Doug_G Lead Moderator

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    Agreed on all points. And it is something of a nuisance that the Energy app keeps defaulting back to Instant.

    Will be interesting to see how range works out in the summer.
     
  3. dsm363

    dsm363 Roadster + Sig Model S

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    pilotSteve: Thank you. Very useful information. Did you mean rated instead of ideal when you said
     
  4. JakeP

    JakeP S P4996 / X P6028

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    I just finished a trip home of 182 miles, outside temp 19F the whole way. Started with a near-full max range charge of 250 miles, and finished the trip with 6 rated/projected remaining. A drop of 10 degrees F makes a significant impact on range. I had cruise set at 55 mph almost the entire way (60-65 mph for the first 40 minutes or so), elevation changes were minimal to moderate (zip code 14719 to 15090), had seats on level 2 for first 40 minutes and then off for the rest of the trip (but they stayed nice and warm), climate set at 67 but only the windshield fan was on, level 5 and later down to 4 and 3. We felt like the crew of Apollo 13 in the LEM Lifeboat scenario, kids were huddled in back under a quilt, and I was seriously considering turning off Nav and the USB Audio to conserve milliamps. Drive was 1 hour daylight, two hours in the dark: headlamps consume energy, also!

    Thanks much to Doug for tips on the climate settings for anti-fog. Using outside air and fan on the windshield, fogging was a non-issue on the return trip...it was a major issue on the way up, when I had recirc on in an attempt to keep the cabin warm.

    I also had the Range Driving mode set to On, and I wonder if that was surreptitiously heating the seats, even though the display showed them as off. I turned this off for the last hour, as things were looking pretty grim. I had a buffer of only *six* miles on my 30-mile average Projected Range, but thankfully it held up for the last two hours of driving, and that is what I arrived with.

    All this tells me that we desperately need the Supercharger network. I did *not* buy this car to drive at 55mph. Nor did I drive it to be a fairweather Sunday driver only!

    The trip there had 30 miles of range to spare when we arrived, but we were ten degrees colder today, which I think was the main difference. I really should have stayed to get the full 265 max range charge, but I turned on climate to HI and seats to 3 to warm the cabin when I hit 30 minutes remaining (showing 250 rate miles, charging at 40A)...and fifteen minutes later, I was still at 250 miles, and it said two hours and fifteen minutes remaining! At that point I pulled the plug and hit the road, hoping to catch daylight. I believe my battery pack was nice and warm, I never got the "Battery Pack is warming, you will have more power as you continue to drive" message.

    Note to Tesla Motors: PLEASE put a Supercharger in Erie, PA. It will be a godsend to everyone traveling I-90 between Chicago-Cleveland-Buffalo-Syracuse, as well as folks heading north on I-79 from Pittsburgh and points south. Plenty of restaurants in the area...overcrowded with them, actually.
     
  5. Doug_G

    Doug_G Lead Moderator

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    Glad to hear you made it... but 6 miles is not much margin!

    Seat heaters and headlights are negligible in terms of power consumption. You're talking dozens of watts versus ten thousand plus to keep the car moving. So feel free to use them liberally. The more important reason to avoid driving at night is that it gets colder.

    Cabin heat uses thousands of watts so it matters a lot more. That's why the Range mode is so useful, and why I suggested turning off cabin heat altogether if you're in risk of falling short.

    Next time you had best finish that Range mode charge! In the winter you need it!

    Anyway I'm glad to hear everything went okay, even if it got a little close.
     
  6. AnOutsider

    AnOutsider S532 # XS27

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    One concern of mine, is how this is going to shake out in X years when our battery capacities begin to drop. If we're (I have similar experiences) "just making it" now... We're screwed in the future unless we get more SC stations. The talk of packs not being upgradable doesn't help :(
     
  7. JakeP

    JakeP S P4996 / X P6028

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    Yes, it was a screwup on my part not to get the full range charge...it was going to finish sooner than we wanted to leave, and I idiotically turned it OFF instead of reducing the amperage to a trickle. And hour later my grandpa showed up and I took him for a drive (his dad was on the list for a Tucker, and he has read about Nikola Tesla, so he was very interested). This killed me because I lost several kWh warming the pack and driving 5-10 miles, so when we got back I was down to 221 rated. So I had to start over the range charge, and then the 30-minute cabin heat then seemed to prevent the range charge from completing, after an hour and fifteen minutes to get from 221 to 250 at an outside temp of 17F, charging at 40A on a welders NEMA 6-50 in the shop.

    How does one shut off Cabin control but maintain outside air flow to the windshield to reduce fogging? I had the cabin set at 67, the lowest it will go besides LO. Should I have had climate OFF, but still somehow selected outside air instead of recirc? I wanted fan on that windscreen, to keep the fogging down!

    - - - Updated - - -

    Here's a pic of my baby charging this morning in white-out conditions southeast of Buffalo. Despite my being shocked at the range loss due to cold, and a rather harrowing experience of making it home with only six miles to spare, let us remember that I absolutely LOVE this car. We just need Superchargers, and I am willing to have patience as an early adopter in this arena!

    TeslaBobCin.jpg
     
  8. kendallpb

    kendallpb Model S: P 8061

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    The battery replacement option (which, once one loses enough range, is a lot like a pack upgrade...) sounds more tempting, reading this thread/your comment. ;-)
     
  9. ModelS1079

    ModelS1079 Member

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    Only disappointment with this otherwise amazing revolutionary car: decreased range in cold weather. JakeP, do you recall your average watts/mile for the trip?
     
  10. Doug_G

    Doug_G Lead Moderator

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    You pretty much have two choices: HVAC off; or HVAC on, select LO temp, outside air, and put it on the windshield. Either way, the windshield will probably still fog up over time, so you can periodically use the DEFOG mode, but sparingly - just enough clear the windshield.

    In my experience, if you keep the heater on in Range mode, you can get maybe 80% of Rated Range (70% of Ideal Range) at best in very cold/humid conditions. I haven't tried it with heat off altogether because I haven't needed it.

    I do have experience with heat completely off in my Roadster. I could get about 80% of Ideal Range in similar conditions. You do get pretty chilled despite the seat heater. I don't know how that might compare to the Model S. I get the impression the Model S does more pack heating than the Roadster, under the same conditions.

    If, in the future, you're that close to the wire then slow down just a bit more. If you knock just a few mph off over the whole trip it will save you a significant amount of energy.
     
  11. pilotSteve

    pilotSteve Member

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    Yes indeed, sorry for the typo and for pointing this out. I've edited the original.

    - - - Updated - - -

    JakeP - funny, something similar happened to me. I did the full Range charge at my friends's house in Bend (he has a shop with a 10-30 welding plug [30A/240V] so I made up a homebrew 10-30 to 6-50 adapter [I know to be careful here, labeled it for Tesla Charging only @ 24A]) and this morning had the full charge.

    Of course then a friend of my friends showed up and he talked me into a test drive. Then my friend's wife (all are true motor heads) took her test drive. We all know how it goes sharing the Tesla grin :)

    Bottom line: I had burned 30 Rated miles before even starting over the mountains for home! But (the major point of my post) is that I feel my sense of usable range and how to drive at close to the Rated budget is coming into focus and I still felt comfortable taking the family on the drive without a 60 minute 'top off charge' delay.

    And it worked out nicely. Granted this was only a 170 mile trip but I had good confidence it would be successful, as it indeed was.
     
  12. JakeP

    JakeP S P4996 / X P6028

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    #12 JakeP, Jan 21, 2013
    Last edited: Jan 21, 2013
    I snapped a pic of the Trip meter when I got home: 186.5 mi, 70.6 kWh, 378 Wh/mi.

    There was some snow on the road for the first hour, and a stiff headwind for approx 30 mins as we approached Lake Erie on I-86.

    - - - Updated - - -

    Yes, indeed! Though how prevalent will superchargers be in 8 years? Maybe you will only ever need to drive 100 miles.

    - - - Updated - - -

    Ok I will fiddle with HVAC off and/or LO. What we need is outside air blown on windscreen only, which should minimize need for power to the fan or heating components, especially at highway speed.

    You are not kidding about slowing down. Our projected range was below our target at our initial highway speed of 65, and at first I thought it was only due to averaging in the previous day fun driving. We adjusted the average window, and saw it truly was below our needed miles. Cranked down speed to 60, and it climbed to barely over our remaining distance. Finally gave in to being a highway jerk out of sheer desperation, set it to 55 and then we hovered between six and eight miles above our target for remainder of the trip, living in fear of each hill.

    I won't take a trip this long again under 32F...I simply did not buy this car to drive 55...call me Sammy Hagar if you must, but I would rather wait for a Supercharger! Cannot wait to do the same trip at 60F for comparison!
     
  13. JakeP

    JakeP S P4996 / X P6028

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    I should probably add that I am running the standard 19" all-season Goodyears, not the Pirellis or the Nokians. I had confirmed the Tire Pressure at 45PSI at temperatures in the low 40s, but I hadn't topped them off before my trip to account for the drop in temperature, so they were likely running a few PSI under 45 due to the cold.
     
  14. JakeP

    JakeP S P4996 / X P6028

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    Crap. Just went down to start cleaning the salt and dirt off the car, and noticed I had given her a completely unwanted and unwarranted Max Range Charge last night, after arriving home. Must have been distracted by unpacking all the luggage...I never sat back in the drivers seat after getting out. Never saw the Range Charge warning or the prompt to set it back to standard after the previous range charge (nearly) finished before our departure.

    I may well the the first idiot to do this, but I doubt I will be the last!
     
  15. Mike_Schlechter

    Mike_Schlechter Model S - P457

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    My car arrived in Max Range charge and when I was at service they swapped it and I didn't notice until the next day when I got in an saw my rated miles. Annoyed that twice it was Tesla that set it to max, and no clear idea why they would do that.
     
  16. pilotSteve

    pilotSteve Member

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    +1 JakeP, Mike -- this is dumb design to have Range stay 'locked in' just because we chose it on rare occasion to prepare for a long trip. Tesla really needs to change this as its contrary to their own advise that this be used only rarely. I started charging after my long trip and was cleaning up my garage. Opened the door and glanced inside to see how the charge was progressing and saw RANGE mode displayed on the 17" screen.

    I don't think the RANGE charge mode is even shown on the instrument screen (I could be wrong) but only by opening the door (hence powering up the large display) could I even tell I was in the wrong charge mode.

    I'm going to email ownership and request this be fixed by always defaulting back to standard charge.
     
  17. JakeP

    JakeP S P4996 / X P6028

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    Definitely agree. You should be forced to specify Range charge every time you want it, as it is the exception case, and is something to be avoided unless necessary.
     
  18. dsm363

    dsm363 Roadster + Sig Model S

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    I agree. If you select range mode charging, there could be a secondary toggle switch below that appears 'stay locked in range mode' that defaults to off as well. That way on a long journey you could leave it in range mode but you'd be responsible for changing it back but at least it would be your choice.
     
  19. montgom626

    montgom626 Active Member

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    The MS battery is doing exactly what it is supposed to do in cold weather, that is, lose range.
     
  20. ggr

    ggr Roadster R80 537, SigS P85 29

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    I know for a fact that you're not first. I don't think I was either.
     

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