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Driving a Roadster close to maximum range

Discussion in 'Roadster: Technical' started by John W. Ratcliff, May 19, 2016.

  1. John W. Ratcliff

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    Since I've only owned my Roadster for about two weeks, I don't yet have any experience about reaching close to the maximum range.

    However, this Saturday, I want to drive it 140 miles (70 miles each way) with zero chance of being able to charge it along the way.

    My car just had it's annual service with Tesla and they reported everything as being in great shape.

    My 'ideal range' on a full maximum range charge is reported as 212 miles.

    In that same state, it reports a usable range of 165 miles; which is 25 miles further than the 140 mile road trip I want to take.

    This sounds like it should be safe..but..I assume there are numerous variables at work. This 140 mile trip will be almost entirely on the freeway going 70mph.

    Based on your experience driving your roadster within 20-30 miles of it's reported usable range, does this seem 'safe' to do, or am I likely to end up getting stranded a short way from home?

    Also, I know there is a 'range' mode for charging, is there also a 'range' mode setting for driving as well?
     
  2. Mitrovic

    Mitrovic Member

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    To me this seems safe. But if you notice that you are getting closer to zero miles at your arrival lift your foot. The Roadster has a built in Range Extender: Your right foot.
     
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  3. MileHighMotoring

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    Charge the car in Range mode - and after it's done, press the TOP OFF button to add a little bit more. Its obviously bad practice to do this often, but once shouldn't hurt anything. As @Mitrovic said, just like in an ICE vehicle, your foot will determine your economy as well. But it'll make it just fine.

    I had a similar concern a few weeks ago and got home with way more miles left "in the tank" than I would have expected. Quick urgent question about charging rate
     
  4. wiztecy

    wiztecy Active Member

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    So what is the 212 mile reading in Range mode and where is this 165 usable miles coming from? That's not the right terminology. The correct terminology is "ideal miles" which is on the VDS screen and "estimated miles" which is on the speedo cluster. The ideal miles is an ideal world situation driving at 55 mph. The estimated miles comes from your previous 60 miles of driving, your driving habits such as hills, downhills, and how much you use or limit your foot on the accelerator.

    With that, when charging in range mode time it so when you're just ready to leave for your trip that the range mode charge is done. Don't worry about top off, I never use that. Just as soon as your range mode charge is done, unplug and go. Then beware, when driving in range mode or when the pack is close to 100% SOC you won't have any regenerative braking. Its scary at first so make sure you understand the Roadster will not stop as fast without regenerative braking. This is so the battery does not overcharge and its a protective mechanism. I typically immediately switch over to stand mode on the VDS when driving, why?, because its an extra reserve for me. I play it in a conservative manner when I do long trips. Regenerative braking still won't be active. Once the SOC has been dropped down to about 90 to 95%, forget the exact area, regenerative braking will kick back on.

    While driving you can switch into range mode to view how many max miles you have left. Also you may want to drive in range mode to get the feel of it, range mode will limit the acceleration of the Roadster to help conserve your energy. I actually want all the power all the time in case of an emergency and limit my energy use with my foot.

    Lastly Range mode has a lower reserve as well, meaning when you drive in std. mode, your miles will start to show 10 miles and then close to 0 miles. This is ok, it will switch over to Range mode unless you do that yourself. You then have about 30 miles left on your range mode / reserve. Note that when you get down to 20 miles in range mode the Roadster cannot calculate how much it has in the battery too well, so it then says "Range Unknown". In that case I switch over into diagnostics mode and view my SOC and the raw battery data to know how much energy my battery has. Don't drive the pack down to zero and if you can try not to use those lower 30 miles unless you have an emergency, its better on the health of the pack. Same with range mode charges, the more range mode charges performed, the more stress is put on the pack.
     
  5. AEdennis

    AEdennis Active Member

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    Might I suggest checking elevation changes to see what your expected consumption will be? (EVtripplanner.com does this) Just select Roadster, Route Direct, don't forget to put your weight in...

    It will give you your expected consumption...

    Lastly, if you even have a chance of 110V charging at the destination, do that if you're worried. But make sure to have Plugshare loaded on your smart phone.
     
  6. John W. Ratcliff

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    Thanks for all of the good advice!
     
  7. tvuolo

    tvuolo Member

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    EV Trip Planner is great. I usually put in 300lbs of payload, and a speed multiplier of 1.2. That usually gets me right around 300 Wh/mi which is pretty average for me doing a steady 70 to 75 mph. But like MileHigh, I always end up with more miles remaining than I was expecting... a good problem to have!

    Wiz, I don't think the SOC has to go down to 90 or even 95% to get regen back. I think it's closer to 98%. Where I remember it kicking back in was 5 miles from my house or roughly 2% (I get 225 ideal on a range charge). The last time I did it, I took off right when it was done range charging, so it should have been pretty near full.
     
  8. Stefan T

    Stefan T Member

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    It's easy to drive 20% under idal if you are careful with speed and the wether is good
    And no high speed roads and heat in the car
    I did 320 km with avrage of 121 wh/km and i could done it bettre with little more carful driving and half and i have of the way with heat in coupe
     
  9. supersnoop

    supersnoop Tesla Roadster #334

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    EV Trip Planner has been off by an order of magnitude when I select the Roadster option.
    I'd try to keep it closer to 60. At 60MPH, you could probably squeeze out 190 miles safely. Power consumption increases exponentially as you go faster.

    Some things to be aware of:
    In "standard" mode, the car will complain when you reach 25 miles remaining and will notify you that it's reducing the power available.
    "Range" mode unlocks an additional 10% of battery capacity. If you hit 0 in "standard" mode, there should be another 25 miles of range hiding in "range" mode. However, in "range" mode, once you reach 10% remaining, the car will complain constantly that it doesn't really know how much power you have left. I'd never do more than 5 miles or so after this point.
    "Range" mode not only unlocks additional capacity, it also reduces the power output. Acceleration will be a little slower in an effort to reduce consumption.

    Personally, I set the VDS to the trip screen and reset the counter, and I set the dash to the estimated range display. As long as estimated range is greater than trip mileage, you should always be able to turn around and get home.
     
  10. wiztecy

    wiztecy Active Member

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    Note that the Roadster doesn't charge more than 97% SOC (from diags) to protect the battery :)

    Also note that with highway driving, no hills, if I set the cruise control to 60-65mph I can have my estimated miles match the ideal miles, that's what you want, to have those match or have the estimated miles creep a little higher than ideal.
     
  11. gregd

    gregd Member

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    For what it's worth, I did a trip last February of 146 miles (one way). My car charges to 215-ish miles in Range mode (165-170 in standard), so very similar to yours. I kept the car in Range mode during the trip, and kept the main cabin heat off (seat warmers are free), and arrived with 70+ miles still available. So, the predicted range was just about right. Range charged at the destination, and made the return trip in similar fashion. Most of the trip was freeway, but with some traffic at times, so the average speed was a bit lower.

    On a round-trip, altitude effects should nearly net out. Speed does make a difference, but unless you crank up the A/C and have a lead foot, you should be fine.
     
  12. supersnoop

    supersnoop Tesla Roadster #334

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    I should note, on that that same VDS trip screen, you can see the average watt-hours-per-mile. Ideal miles are based on about 230Wh/m. If you keep it at or below that, you'll be fine. For your range, you'll probably be fine up in to the 260Wh/m area. I have a 200 mile trip that I normally take at an average of 58MPH, and I can make it on one range charge, arriving right when the car reaches 10% remaining.
     
  13. jerry505

    jerry505 Member

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    Why not plug in at your destination? A standard outlet is slow charging, but every little bit helps.
     
  14. hcsharp

    hcsharp Active Member

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    Hmmm... I see where the expression "Your mileage may vary" comes from. If I drive 60mph with no heat, AC off or on low, it's not raining, and it's warm outside I will virtually always equal or beat ideal miles. I routinely pick up/drop off people at an airport that is 104 miles from my home, 92% highway at 65mph. I've never had a problem doing the round trip 208 mi unless it's raining or snowing and I need to use defrost. Even then usually all I have to do is slow down.

    If you don't believe me, perhaps the Roadster owner on this forum who I picked up and dropped off at that airport will chime in. When dropping him off we were having so much fun talking that I missed the exit and drove 20 miles out of my way. I still made it home without charging.

    John - I don't know what you mean by "usable" miles. There is no such thing on the Roadster. Do you mean "estimated" miles? They imply two different things. I don't use estimated miles very often because it's only based on your driving patterns of the last 30 miles. Once you get used to applying a factor to the ideal miles based on what's ahead, you will find it more useful IMO.

    I'll end this post the way I started - YMMV.:)
     
  15. Stefan T

    Stefan T Member

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    And one more thing, the tires make big diffrece if you have Yokohama tires or other that are low roling recistance
    I have Dunlop Blue sports with low rolling recistance
     
  16. dhrivnak

    dhrivnak Active Member

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    I
    I agree with Henry as I routinely make 200 mile trips. If I do not need HVAC and there is no strong headwind or rain I can do a little better than ideal miles by keeping the speed under 60. My record is 244 miles whe the VDS said 224 ideal miles.

    But rain and HVAC can easily drop my range 20%.

    And while I am not sure if I am the person Henry is talking about he did pick me up at the airport and we did drive 100 miles to his lovely home. When he picked me up his battery was just over half so the math worked out.
     
  17. tvuolo

    tvuolo Member

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    Ahh! Then your estimate is pretty accurate. I did not know that 97% was max.
     
  18. tvuolo

    tvuolo Member

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    When I range charge, it's usually to go somewhere with my wife. She either has max heat, or max AC... there is no inbetween. ;-)
     
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  19. gregd

    gregd Member

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    ...which is why the Roadster comes with a small trunk :)
     
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  20. John W. Ratcliff

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    I meant the difference between 'ideal range' and the *actual* miles you can get based on your driving style. For example, my car might show 212 'ideal range' but on the dashboard, based on my current driving style I suppose, it's shows a much smaller number, which I figured was the 'actual range' you can realistically expect.
     

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