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Charging, limits, and predicted charge level at destination

Discussion in 'Model S' started by D.E., Jul 26, 2017.

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  1. D.E.

    D.E. Member

    Joined:
    Oct 12, 2016
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    Location:
    Chattanooga, TN
    If have my charge limit set to 80% which should be a little over 200 miles, is it normal for the supercharger to exceed the limit and go for a full charge? I get phone notification of sufficient charge to continue on the trip but charging doesn't stop at my selected level.

    How about on cross country trips where the Tesla navigation calls for charging en route, does the car override my limits in order to provide more charge buffer for the next charging stop?

    When I've charged, I've seen a next charger arrival prediction of 7% charge. With interstate driving at 70-75 MPH the prediction rises and winds up at 20% by the next charger arrival. That is with clear weather, flat roads, steady traffic, 85-90F ambient with A/C set to 70F. Is this what others see? Measured consumption is about 290 or so watts/mile over a 30 mile average. Is there a way to see what value the car is using for predicting consumption in the calculation of residual arrival charge?
     
  2. KarenRei

    KarenRei KarenRei KarenRei KarenRei KarenRei KarenRei

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    According to the Tesla range calculator, at a steady ~75mph, 86°F, AC on, 19" wheels on a 75D, and with the 75D's usable battery capacity of 72,6kWh, you should get 325Wh/mi. At ~68mph, same conditions, it should be 293 Wh/mi.

    Other factors not mentioned by you that can improve range:

    1) Wind: While headwind and crosswinds reduce range, tailwinds increase it
    2) Terrain: Even subtle terrain variations can have a significant impact on range. What matters most is the difference in height between start and endpoint (although if you have to start regen going downhill, obviously that significantly lowers range versus a more gradual decline)
    3) Tire age: Old tires, surprisingly, have lower rolling resistance than new ones. The tread becomes harder and thinner.

    There's also a number of factors which can decrease range, such as aging on the pack, aging on the drivetrain, loose panels, windows down, uneven acceleration profiles, and so forth.

    But in general, your numbers sound quite reasonable.
     
    • Helpful x 1
  3. appleguru

    appleguru Member

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    Location:
    US
    Supercharger will charge to the limit you set.

    It will alert you when it thinks you have enough charge to make it to your next stop, but won't stop charging until it reaches your set limit (or a fault occurs).
     
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  4. animorph

    animorph Member

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    Location:
    Scottsdale, AZ
    Usually I have to deal with the destination charge estimate declining, so your doing pretty good. But it always depends on the particular terrain. For the Interstates it was usually pretty close.

    My first drive from Scottsdale to the Holbrook AZ SC had lots of elevation changes. Although it looked easily doable in my X100D on EVTripPlanner, with 20% remaining at the end, at times the car was freaking out, estimating -6% at the end and telling me to slow down. Mostly that was when I was going uphill for a while. I went with EVTP, kept driving normally, and got to Holbrook with right about 20%. However, for other segments of the road trip the in-car planner was more accurate than EVTP. And both were usually a little optimistic for our driving. I think we had only two segments out of about 40 where I had to slow down about 3 MPH to keep the destination charge estimate at 10% or above.
     
  5. mspohr

    mspohr Active Member

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    Location:
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    Couple of things here:
    - Charging should stop at the level you've set regardless of whether or not you are Supercharging. If it's not stopping, contact service.
    You will get various notifications during charging such as "Charging almost complete" and "You have enough charge to continue".

    - The estimates of charge remaining at the destination are just that, estimates, and can vary with a lot of factors... temperature, speed, wind, rain, snow, etc.
    I use the energy monitor (top center of the screen... it's the graph icon) to watch my consumption as I drive if I have any concern about range. It will adjust it's estimates every few miles based on your actual usage. It usually starts out somewhat pessimistic about range. If it looks like you are going to run short, just slow down. That will increase your mileage.
     
    • Informative x 1
  6. D.E.

    D.E. Member

    Joined:
    Oct 12, 2016
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    Location:
    Chattanooga, TN

    Home charging stops, supercharger charging continued through the limit. I've got an update since then so I'll need to recheck before contacting service. I do get the notifications.

    Many thanks.
     

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