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Should Supercharging Respect Charge Limit?

Discussion in 'Model S: Battery & Charging' started by VxJasonxV, Oct 14, 2016.

  1. VxJasonxV

    VxJasonxV Member

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    Hi folks, I've been an 85D owner for a bit over a year, and am consistently blown away by the substantive updates Tesla Motors continues to push out. I've been thinking about various optimizations and convenience features that they could include after being inspired by the now fully automatic Homelink since taking delivery of my car.

    One feature that I wonder about is Supercharger behavior. I alternate between limiting my charge to ~155 miles of range and ~200 miles of range depending on the amount of city driving I may be doing, but that got me thinking; I very occasionally use a nearby Supercharger for a quick bump if needed, and as far as I recall, it only charges up to the limit you've set.

    Considering that we don't directly pay for Supercharger energy, and the scheduling/limiting controls on the display are disabled when using a supercharger, should it respect your set charging range?

    My current opinion is:

    A Supercharger should always charge up to full 90% "Daily" range, but up to 100% if set.
    Put another way, it should never charge lower than 90%, but should charge up to 100%.

    Do any of you have a reason for why you'd want the Supercharger to respect your set charge limit?
     
  2. Max*

    Max* Autopilot != Autonomous

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    :facepalm:
     
  3. mikeash

    mikeash Active Member

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    The only real reason to have a charge limit in the first place is to go easier on the battery, and that applies equally at SCs as anywhere else. I don't see why it should act differently there at all. I'd be very confused if I set a lower charge limit and then an SC blew right past it.
     
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  4. Rocky_H

    Rocky_H Member

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    I am already thinking of several sarcastic analogies to this, but the forum police will get me, so I'll just say that I hate that idea.
     
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  5. evp

    evp Nerd

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    Another reason: going across country, you want to stop charging when you have enough juice to make the next SpC, so you don't waste time in taper. Added bonus - the car will notify you at the lunch counter when it's getting close to your commanded charge level so you can move your car out of the way of the next person waiting to charge. This will become more important when we have 400,000 new Model 3s waiting in line.
     
  6. TES-E

    TES-E Member

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    I absolutely want it to respect the limits I have set. They are there for a reason.
     
  7. VxJasonxV

    VxJasonxV Member

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    #7 VxJasonxV, Oct 14, 2016
    Last edited: Oct 14, 2016
    I chose my words very deliberately. We don't pay to plug into a Supercharger, nor are we invoiced. Yes, the charge is rolled into the cost of the car, but you don't pay at an SC per use.

    I definitely thought about this, but it's not a negative problem. So you come away with *more* energy and *more* miles of range? There's nothing wrong with that. And yes, I set about a 70% charge limit myself. That said, I posted this because of my own personal desire for the charge to exceed beyond that when at Superchargers, without having to continually change the setting. The display can easily communicate that it will charge up to 90% unless set higher, the same way that it disables the charge rate and scheduling settings. It could just replace those when plugged into a Supercharger.

    I *always* charge beyond when it says I have sufficient charge. If I don't, I always get "stay below $mph" warnings.

    Sufficient charge notifications already happen. If you're just driving, at an SC you get: Starting charge, nearly done, and done notifications. IIRC, the "nearly done" notification is a fixed amount to complete, not 20% until your set limit. If you have a trip set, you get; Starting charge, sufficient charge, and if you let it continue, you still get the nearly done generally, and done supercharging notifications. Adding another one for "reached your set charge level while supercharging" seems reasonable to me.

    I may be the uncommon case here, because there is a supercharger just about 20 minutes away from me. That said, I've only ever used that supercharger around 10-15 times in my 1 1/2 years of ownership, and a good amount of those have only been short term use in demonstration for others. Though this brings up another question, how does the display notify you that your set charge level is too short to make it to the next supercharger when on a trip?

    And that reason is... ? All I'm asking for are reasons.
     
  8. WannabeOwner

    WannabeOwner Member

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    You could set your charge limit at supercharger to 100%

    Then check your phone to see when it is approaching having enough for the next leg ... but if you are still waiting for the kids to finish up, whatever, so if it takes you 5 - 10 minutes longer getting back to the car it might as well be charging, rather than just sitting there.

    You could leave a note on the windscreen with anticipated finish time (for the charge you need) and phone number. If someone needs your spot they are welcome to call you

    That said: If your car is set to charge limit 100% and you have navigation on (for the next stop) will you get a notification when you have enough charge, rather than when you are approaching 100%?

    I suppose you could also set the Charge Limit to 43% (whatever you actually need for the next leg) and then when you get the notification if the kids etc. are not ready just increase the charge limit from your phone?
     
  9. Chuq

    Chuq Member

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    As I understand it, the issue isn't reaching 100% charge, but sitting at 100% SOC for a long period of time.

    When you are charging at home overnight, you may not be heading out straight away the next morning - in fact you may even be at home all day.
    When you are charging at a supercharger, you are going to start driving straight away once you are done, usually for a long distance.

    My Leaf works the same way - when the timer kicks (11pm - 7am), it will only charge to 80%. But if I activate it from my phone, or if I'm somewhere else during the day and plug in to a charger, it will keep going to 100%.
     
  10. mattmass

    mattmass Member

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    While I am in general agreement that the user-set limit should be respected, I have a question. What happens if I've limited charging to 70%, but arrive at a SC where the trip planner wants me to charge to 80%?
     
  11. SDRick

    SDRick Member

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    I like the idea. It makes sense to me. With proper notification, I see no downside.
     
  12. bxr140

    bxr140 Member

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    IMO, we've kinda moved beyond the charge limit slider--there's really no technical need for it, and in fact it perpetuates unnecessary paranoia amongst owners. This thread is case in point: It wouldn't exist if there wasn't the option in the first place.

    I know people think they want more control, but I believe tesla owners as a whole would be better off with sensible, discrete settings, even if that means a handful if people looking for (so to speak) android flexibility end up with iOS rigidity.

    Pick your terminology and pick your percentage, but i think what tesla owners really need boils down to: Daily, Trip, and Storage.
     
  13. VxJasonxV

    VxJasonxV Member

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    And now that Tesla Motors has announced that Superchargers will no longer be free for life as of cars manufactured in 2017 forward, the charge limit makes sense again. So...
     

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