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Superchargers A and B lane slots

Discussion in 'Model S: Battery & Charging' started by modelx007, Mar 5, 2016.

  1. modelx007

    modelx007 Member

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    I've read that proper etiquette when pulling into a supercharger is first go to a slot where someone isn't in the A or B slot. But then if you have no choice but to use the slot next to someone else, does it slow down charging for that person too and how much? I'd think that person says "I hope they don't use the slot next to me and pick that other one next to someone else"? If this is the case do others have this go through your thoughts?
     
  2. bmah

    bmah Obscure Member

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    The car that's already there in the paired slot gets priority...it takes whatever current it can handle and you get whatever's left. As the other car's battery gets closer to "full", it begins to slow down its rate of charging and more current becomes available for your car. If that car leaves before you do, then you become "the car that's already there" and you get priority over the next car.
     
  3. studiojon

    studiojon Member

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    The A and B of each number are powered together. Therefore if someone is in an A slot, try not to park in the corresponding numbered B slot as this will be slower for both of you.

    Also in some locations the A and B slots for a given number are not next to each other so you have to look carefully.
     
  4. Saghost

    Saghost Active Member

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    "For both of you"? That's not my understanding.

    The lone car that was already charging got as much power as it could take before you arrived, and I don't believe its power gets reduced.

    The newly arrived car gets much less power than it might want, but I don't believe it hurts the car that was already charging at all.
     
  5. Adrian

    Adrian Title(D)

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    Not true. First car to connect gets priority, it gets whatever it can take. The subsequent cars to connect will get what's left. If the first car plugs out and in for just a second or two, it'll drop in priority.
     
  6. bmah

    bmah Obscure Member

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    Not to dog pile, but no.

    This part here is actually correct. In most places, the A and B stalls are next to each other, but it's believed that Tesla was for awhile experimenting with some other Supercharger configurations, which resulted in some other configurations. Also some sites are for various reasons just "odd", one example is Petaluma, which has both head-in and back-in/pull-through stalls, and where the stalls in most pairs are adjacent except for one pair that has its stalls on opposite corners of the site.
     
  7. roblab

    roblab Active Member

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    Thank you. You're right.

    Understand that every car that charges starts out at a high rate of charge, and then almost immediately starts tapering off to protect the battery pack. Nobody charges at full rate more than a few minutes. Nobody. And unless you can see their screen, you have no way of telling.

    A car may pull in to charge, with a hundred miles still in the pack. The charger ramps up to the rate that is safe for that battery. If the car has only 25 miles on the pack, the batteries can take a higher rate of charge for a few minutes. If the battery is hot, the charge rate is reduced while the fans cool the pack.

    What this says is that hardly any car will start with getting full charge (lets say 120 kW), and then it gets highest charge ONLY for a few minutes. The charger quickly starts to ramp down. You can see this on your charge screen by watching how many miles per hour of charge you are getting, and it drops minute by minute.

    What this also means is that, into the charging cycle a few minutes, the charger is not putting out full power, and a second car can plug in to charge with what's left of the 120 kW.

    The problem is, you can not know what the first car is getting. If they have been of the charger for 30 min, the second car will get almost full charge, almost as fast as if car #1 was not there. If, on the other hand, car #1 just pulled in with 10 miles of charge left, car #2 will get a smaller amount, which also depends on the charge of car #2.

    So. Try to pick a stall that is not sharing. if you must share, and have a choice, pull into the spot beside the car where the lady is reading her book: She's probably been waiting, and her car is ramping down, and she will leave. Better yet, get out your own book.
     
  8. Mike K

    Mike K Member

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    To correct a statement that was previously made, I've noticed that power doesn't automatically ramp up when that other car leaves. You need to stop charging and re-start to take advantage of the newly available current. I vaguely recall reading this somewhere and it's been my experience as well the few times I've shared a charger.
     
  9. omarsultan

    omarsultan Active Member

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    I do not believe that is true, its certainly not my experience: first car gets priority, as soon as that car is done the second car gets priority, no driver intervention needed.
     
  10. OddB

    OddB Member

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    Choose the stall next to the car that has the slowest blinking green light at the charge port.
    (If people are sitting in the cars that is...)
    On rare occations the first on a shared charger CAN get a small reduction in power. That happens when the first is charging at full power. (110kW+) as the second gets at last two of the partial chargers (22kW) -EU
     
  11. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    Be careful of saying next to... Some sites have the A, B paired stalls next to each other, and some don't. For example, I have seen both of these orderings for a 3, Supercharger, 6-Stall site:
    1A 1B 2A 2B 3A 3B
    1A 2A 3A 1B 2B 3B

    There does not seem to be a rule. You just have to look at the pedestals.
     
  12. Saghost

    Saghost Active Member

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    Tesla knows the status of all stalls in real time, right? So I'm thinking/hoping that at some point they'll release an update and when you approach the SpC area, it'll bring up a map of the group and highlight the best option for you (as in, a remaining unpaired station if any are free, or the one paired with the car using the least power.)
     
  13. Mike K

    Mike K Member

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    I've never seen current rise as that first car pulls out though and I vaguely remember reading somewhere that this was normal. For you to take advantage of the newly available current you'd need to stop charging and start again. I had this perfect storm play out last week at the Burbank, Ca supercharger. I pulled in with probably 40 or 50 miles with one stall available. I started charging and the other car took off about a minute later with no change in my charging speed/ amperage. I had to stop charging and re-start before it ramped up. I removed the charge cable briefly as well but I'm not sure if that is or isn't necessary.
     
  14. OddB

    OddB Member

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    Are you looking at mi/h ( km/t) or kWh /A and V ?
     
  15. Max*

    Max* Autopilot != Autonomous

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    Once the other car leaves, you get priority.

    Your current does rise, I've seen it. I've heard the myth that you need to go unplug and re-plug yourself, but I have tested it, and that's not true. Just give it a little bit of time (I don't know, maybe 10 seconds?), and your rate of charge will shoot way up.
     
  16. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    I have always found the power goes up in the secondary car as the primary car tapers or leaves.

    I think that @OddB has hit the mark on this perception that one needs to disconnect and reconnect. The Model S has had the quirk from the first deliveries that charging kW is displayed as the instantaneous value, while the charging mph is displayed as the average for the session. Because charging mph is an average for the session, it will slowly rise as the instantaneous value steps up immediately. By restarting the charging session, you restart the averaging, and get the perception that charging has sped up.

    If you display charging mph (which is an average of the session), you can always calculate charging power in kW as V*A/1000, or the instantaneous mph as V*A/300 or kW/0.3

    If someone has not seen kW or instantaneous mph rise when the primary car tapers or leaves, please report that.


    BTW, the temporal distortion caused by displaying charging mph as the average of the session works the other way. During a Supercharger session, tha actual, instantaneous charging mph drops much more and faster than the displayed, average mph.
     
  17. Rocky_H

    Rocky_H Member

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    I think several of you were incorrect on this, and OddB is correct. I had read quite some time ago that in pairing, the secondary car will get a minimum of about 30kW. So if the priority car is almost empty, and is wanting to pull about 110-115kW, it may be slightly limited by the secondary car splitting it to 90+30 for a 120kW Supercharger. Now as most people have said, this hardly ever makes a difference for long for the primary car, since it will be down to 90kW anyway within about 5-10 minutes from its battery getting a bit less empty.

    And on the other topic of auto-rising or not when the primary car leaves, there is what it is supposed to do and what it does do, which are not always the same. As Max said, it is supposed to auto-increase once the primary car leaves, and I think usually does, but I have read many many reports of that being kind of buggy, where it just won’t. So clicking the button to briefly disconnect it will reset that logic and make it perceive you as the primary car if it is not working as it should.
     
  18. LetsGoFast

    LetsGoFast Active Member

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    This is my experience as well. I see this all the time at Newark, where there are only four stalls and it is extremely uncommon that you get a pair to yourself. If I'm watching the app, it is super-obvious when the other car disconnects.
     
  19. OddB

    OddB Member

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    Solli SOC.jpg
    Here is "proof" of the second car affecting charging power of the first. Blue is Charging power in kW, red is SOC reported by car.. Second car connects at 5 minutes, after 13 minutes the SOC is so high that it dosent matter. minimal total effect, maybe one minute extra charging...
     
  20. Rocky_H

    Rocky_H Member

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    That is really cool; thanks for the graph. That is probably one of the 135kW Superchargers that Europe mostly has. In the graph, it looks like your charging rate goes down to approximately 108kW. So that would be diverting about 27kW to the second car.
     

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