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Is Ideal Range obtainable?

Discussion in 'Roadster' started by benji4, Mar 2, 2011.

  1. benji4

    benji4 Roadster 2.5 #0476

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    I just got my car one week ago (Base model 2.5, Obsidian Black, black forged alloy wheels), but something doesn't seem right on my car regarding the Ideal Range displayed on the VDS. Over that past 3 days, I've done a number of tests where I drive between 20km and 30km as conservatively as I can, and see if I can get my actual mileage to match what is displayed as "ideal". Here are some points:

    1) All my driving has been done at night with lights on, stereo on, heater off.
    2) All city driving, a lot of stop and go.
    3) Accelerate very slowly, max speed about 60km/hr, no friction braking used if at all possible to avoid it. Anyway, I'm driving as "ideal" as I possibly can for these tests.
    4) Outside temperature is quite cool, but not freezing.
    5) Fairly flat course.
    6) Driving alone, I weigh about 85kg.
    7) Soft top is on the car...
    8) Ideal km remaining seems to drop in 2km increments most of the time (sometimes 1km, but more often 2km which seems strange)
    9) Charing in standard mode with 100V / 15A. Generally I start off with the battery pack about 1/2 full.
    10) All driving done in standard mode.

    Anyway, pretty consistently I'm getting 20-25% less ideal km than the VDS shows, even though by all counts I'm driving in a manner that should yield the ideal range at least! The other thing that seems strange is that I went for a drive in a Tesla demo car today (2 people in the car), and conservative driving seemed to make actual mileage and ideal range track pretty closely. The demo car is also a brand new 2.5, but a sport in this case.

    * Could it be because my car is new (just 3 or 4 charges so far)? The demo car was new, but it has more than 2000km logged so far.
    * Is it possible something is wrong with the ESS?
    * Do different cars just have different efficiencies depending on the car? (20-25% seems like a pretty big variance though!)
    * Are my 20-30 km drives just too short? (we just went 6km or so in the demo car though, and it seemed to track)
    * Could it be it's just too much stop and go? Should I expect 20-25% percent less range in such an environment even when driving like a grandma?

    Unfortunately I had to take the car back to the dealer today because a reflector fell off the back, but should be back tomorrow. I'll get the log analyzer fired up and see if that might offer any clues.... would be helpful to hear about peoples' experiences in trying to get ideal range out of the car, and how it's possible to do it.
     
  2. Eberhard

    Eberhard #421 Model S #S32

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    Hi benji4,

    first think you have to do: increase your tire pressure to range level (2.1 front 2.8 back).

    It takes time to adjust estimate range to ideal range because it been calculated over a long distance (200-300km?). On my last trip over 5200km i got often an higher estimated range then ideal range. my highest estimated range was 610km when i descent from the pyrenees mountains from 1600m to 100m over a distant of 80km. Ideal range declined from 304 to 272km in Standard mode.

    you may match ideal range with driving around a consumption of 140Wh/km and less
     
  3. AndrewBissell

    AndrewBissell Member

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    I guess the 2km drops interspersed with 1km drops might arise from the underlying measure being in miles with a simple rounding to km.
     
  4. AndrewBissell

    AndrewBissell Member

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    I have observed that even using no cabin heat, energy consumed goes up dramatically when temperature drops from say 12C to say 2C. I guess this relates to pack heating requirements. If you drove the store demo car in the day and your own at night, if there was a difference of that kind it would contribute (I note that seems about right for Tokyo currently).
     
  5. Dragon

    Dragon Lightning Green Fairytale

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    The reflector fell off on a brand new car? WTF? Was it placed there with a chewing gum?
     
  6. benji4

    benji4 Roadster 2.5 #0476

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    Yes, the reflectors below the rear bumper actually are glued on with something that does look very much like chewing gum! The left one fell off (and unbelievably I was able to find it later the next day in the street where I thought I heard something fall off), and the right one looks like it is about to fall off as well. The dealer said they are having this problem with a number of new cars that have come in lately... that's Lotus engineering!
     
  7. benji4

    benji4 Roadster 2.5 #0476

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    Yes, generally this has been the case, and last night during my drive the little snowflake indicator even came on. However, today on my 5 km drive to the dealer from my house at around 12C, I was still dropping off a lot more ideal km that what I saw on the dealer car. I believe I was running at about 125Wh/km (I really was going slow!), but I'll need to test further... anyway, still just not sure why I am not hitting closer to ideal range in these conditions. I will adjust the tire pressure as Eberhard recommends....
     
  8. donauker

    donauker Member

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    From my experience you will not get close to ideal range with any significant amount of stop and go driving. Regen is certainly a help but it is not close to 100% efficient. The only time I see ideal is open road driving with a limited amount of stops at 45 to 55 mph and in moderate weather.
     
  9. Lancelac

    Lancelac 2010 Roadster Sport #690

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    donauker is correct. It's driving in a straight line at 40-50mph that will get you the best mileage, not stop and go at those speeds. You can see on the tach, that even mild acceleration uses much more energy than staying at constant moderate rate of speed. I don't really try to conserve energy around town, and end up getting about 60-75% of ideal. But when I make longer trips, it is another story. At 50mph, I reliably get 100-105% of ideal. At 60mph I reliably get 88-94%, At 70mph it's 75-80%, At 80mph 63-68%, 90mph = 50-55%.
     
  10. benji4

    benji4 Roadster 2.5 #0476

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    #10 benji4, Mar 3, 2011
    Last edited: Mar 3, 2011
    Thanks for the helpful comments... what it seems like my problems are from reading these posts so far:

    1) Stop and go driving.
    2) Relatively cool weather.
    3) Tire pressure settings.

    This weekend I'm going to do some much long controlled driving on the expressway and we'll see how I do then (if the dealer gives me the car back of course!!!)

    edit: actually, I just thought of something -- the dealer said that ideal range is based on the EPA cycle and is thus a mix of highway and city type driving. That would indicate that just going in a straight line at 50mph should yield some very good results beyond what ideal range shows.
     
  11. ckessel

    ckessel Active Member

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    That's good to know. Dissapointing, but good to know. It means the Model S 240 mile or 300 mile range really isn't close to realistic. When you're traveling 250 miles, most if it is going to be 70mph freeway speed, so a "300 mile range" is really more like a "225 mile range" for anything resembling normal distance driving. It confirms for me that the 300 mile battery on the Model S is an absolute must have.
     
  12. tennis_trs

    tennis_trs 2010 2.0 Roadster Sport

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    The distance I've seen written about before is the previous 30 miles.
     
  13. benji4

    benji4 Roadster 2.5 #0476

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    #13 benji4, Mar 3, 2011
    Last edited: Mar 5, 2011
    In my opinion, "estimated range" is really pretty meaningless because there is no way the car is going to know things such as what my course will be for the drive, how fast I'll go, how many times I'll stop, etc. Ideal range is much more meaningful I think because you should be able to hit it if you drive conservatively, do better if you drive REALLY conseratively, and do worse if you do "spirited driving". The dealer tells me I should shoot for 200 Wh/mi to do better than ideal, around 250 Wh/mi to match it, and don't worry about it at all if I don't care about range for any particular drive. He says that he hits about 325 Wh/mi when he drives aggresively. Rather than estimated range, it would almost be nice if you could dial in a targed kw/mi number or at least punch in what type of style and course your are going to be driving on.... but anyway, just having ideal range shown and making a mental adjustment is fine too --- IF I could somehow hit it now and then! I'll report back after my long controlled drive on the expressway this weekend. I'll be going about 200km total with one stop in the middle only.
     
  14. Doug_G

    Doug_G Lead Moderator

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    Benji4, bear in mind for your test that speed matters quite a lot. See Roadster Efficiency and Range | Blog | Tesla Motors

    If you drive slowly but at a constant speed you will maximize the range. In theory, from the graph, you could drive over 650 km on a charge, but you'd have to drive the car verrrry slowly for nearly 24 hours!
     
  15. Sparrow

    Sparrow S105/ Roadster 189

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    On my 2008 Roadster it seems that something like 230 WH/mile plus or minus is closer to "Ideal". So far conservative driving in moderate temperatures around 60F can yield me something closer to 220 WH/mile and thus I beat the Ideal value.
     
  16. cinergi

    cinergi Active Member

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    EM is based on the last 40 miles (64.3km) of driving, so you'll need to drive at least that far in "conservative mode" to see it.
    My EM went over IM on my commute without trying (I just happened also not to be aggressively driving). 16 miles each way with 6 stop lights and various speed limits (ranging from 30 to 50 MPH) just after rush hour (so still plenty of traffic and cars in the way causing me to slow down and speed up a lot). 30-35 minutes of driving (so average speed is 30 MPH). This is only possible if I'm not running the heat.
     
  17. stenkb

    stenkb Roadster 938 Model S 5957

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    #17 stenkb, Mar 3, 2011
    Last edited: Mar 3, 2011
    I can leave with a full charge on range mode of 400 km - I drive 180 km at highway speed and I have about 40 km left...of course depending how fast you are driving...
     
  18. samcarney

    samcarney Sam C

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    Benji4; Cruise control on the highway is a must to get the best range. Have fun!
     
  19. benji4

    benji4 Roadster 2.5 #0476

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    Thanks Sam! I previously drove and Estima Hybrid (Toyota hybrid minivan sold only in Japan unfortunately) and a late model Prius. In both cases I did much better with cruise control for highway driving and could even get 60mpg+ in the Prius much of time.

    BTW, looks like the CarbonOne hood and spoiler project is coming along well, am really looking forward to seeing the new parts! Maybe these lighter parts will also improve range :smile:
     
  20. Lloyd

    Lloyd Active Member

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    I have a story about the Prius. I rented one in Los Angeles. I wanted to see how bad I could make the gas mileage. I drove about 250 miles with this car, Jackrabbit starts, floored it wherever I could 80 mph on the highway, used the brakes hard, etc. I still got 41 mpg! I was shocked and impressed.
     

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