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Can charge but cannot supercharge

Discussion in 'Model S: Battery & Charging' started by Rockster, Sep 2, 2018.

  1. Rockster

    Rockster Active Member

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    After taking a short road trip out of the metroplex yesterday in my Model S, I stopped at the Southlake, TX supercharger to charge for the final leg home. The supercharging began, as normal, drawing about 90 kW. After a few minutes, however, the main display switched to "Charging Stopped." Plugging and unplugging and switching stalls didn't help. Each time I plugged in and car would display "Charging will begin momentarily," for a few minutes, and then switch to "Charging Stopped."

    Since then, I've charged successfully at two wall chargers but supercharging still doesn't work, even when trying at the Plano supercharger. (The only difference was that while at the Plano supercharger the instrument display periodically displayed a message saying "Cannot charge. Unplug and try again.")

    I spent nearly an hour on the phone with roadside assistance while at the Southlake supercharger and the technical people who dug into the issue were unable to identify a cause. We've scheduled a service appointment for Wednesday but I wanted to see if anyone had any ideas in the meantime.
     
  2. AustinP

    AustinP Member

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    I had the opposite experience: only SuC and Tesla Dec worked. UMC and public chargers not anymore. After many parts changes, SeC identified it was the high power junction box that needed replacement.
     
  3. Rockster

    Rockster Active Member

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    Interesting. I wonder if that component has two failure modes, one that prevents Supercharging and one that prevents AC charging? I wonder, too, how expensive this repair is going to be, now that I'm out of warranty. :(
     
  4. AustinP

    AustinP Member

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    Happened to our car just before end of warranty so can’t tell you what that did cost.
    Hope they associate it with the battery and drive train for you.
     
  5. gimmi80

    gimmi80 Member

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    It happened to me too. The in car charger has two separate wiring one for ac charging and one for dc charging.
    It was approx $3000 to replace the charger.
     
  6. David99

    David99 Active Member

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    The car doesn't have separate wiring for AC and DC. The info comes from Jason Hughes, and everyone that has taken a Tesla apart will confirm. The onboard chargers (that take AC) will just ignore the DC current during Supercharging. They are not disconnected from the power when charging at a Supercharger. There is a disconnect between the incoming power cables and the battery which will only close when the handshake with the Supercharger is successful.

    There is some error that prevents you from Supercharging and the car is not very helpful telling you why. Tesla can pull the logs from the car and get detailed info what is going on. We can just guess from here.

    That's messed up. The onboard chargers have nothing to do with Supercharging. Swapping them out because of a Supercharging problem seems very odd.
     
  7. MP3Mike

    MP3Mike Well-Known Member

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    Well they do actually have something to do with it because they are exposed to the charging power and have to ignore it. If a component in the charger has failed that is causing an isolation leak, or something else, then it certainly will impact Supercharging.
     
  8. David99

    David99 Active Member

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    Possible, but since the AC chargers work fine according to the OP, I doubt they have an issue. DC current just doesn't do anything to the chargers as they only work on AC. By design there should not be any power going through them whatsoever when DC is present.
     
  9. thecloud

    thecloud As rhythm raced inside, the ship came alive

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    When I was at the Tejon Ranch supercharger recently, I talked to another Model S owner who was sitting on hold with Roadside Assistance, having this same problem. He could charge normally from J1772 or the wall charger, but supercharging did not work. Ended up loaning him an adapter, and when we met up later, he told me that Tesla's diagnosis was that the contactors and main charger needed to be replaced.

    I took it as a reminder to always bring the UMC, the 14-50 extension cord, and all possible adapters with me on a long trip, even if it seems like there are going to be superchargers every few miles along the way. If you can't supercharge, it's like being thirsty on a boat in the middle of the ocean.
     
    • Informative x 1
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  10. Rockster

    Rockster Active Member

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    It seemed that’s what the technical people to whom roadside assistance escalated the call were doing. They made reference during the call to “seeing the successful charging the night before” but not seeing anything anything amiss. I really expected them to see something in the logs. Puzzling.
     
  11. cmf

    cmf Member

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    I had this happen to me recently, ironically on a trip to McKinney from Atlanta.

    The car had trouble starting to charge at Superchargers along I-20 and finally when I got a hold of roadside they were able to see that the DC charger had developed a 'leak' which I thought was an odd symptom description. On my trip I had no choice but to wait at the various superchargers before charging would begin, sometimes taking 30 minutes just for the charge to start. I had the same display messages of "Charging will begin momentarily," and "Charging Stopped." It would just cycle through those messages and the charge ring would flash blue. Luckily it would end up charging but took a long time.

    Destination charging worked just fine.

    I ended up at the Plano service center and they ordered a new charger.
    I'm still under warranty, but I asked how much the part was and it was $2000, not including labor.

    I can dig out the part number if it helps.
     
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  12. Rockster

    Rockster Active Member

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    This is very helpful, thank you. Your post reminds me that my charge port, too, was flashing blue during this fun.
     
  13. EVCarGUy

    EVCarGUy Member

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    I had a similar, occasional, problem at superchargers. In my case, March 2015 S85D, Tesla replaced the "High Voltage Junction Box" under the rear seat. Among other things, it switches the power coming from the charging port either directly to the battery for Supercharging, or to the onboard charger (dual chargers in my case) for L2 charging. $1000 plus labor, plus $155 plus labor 12v battery because the HVJB needed a firmware update, and after 4 hours of trying, the Ranger gave up. The 12v battery had been run down and died. The car was a brick because the firmware update didn't work. It had to be trucked to the SC, and it took a week to get my car back.
     
    • Informative x 1
  14. N..8

    N..8 Member

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    This could be the HVJB you have the 2 50 Amp and 1 100 Amp but these won't be the issue. Here is a cut and paste from the manual about the HVJB.

    The HVJB allows current to flow between the HV Battery, drive inverter, DC-DC converter, onboard charger(s), and the charge port. An HVIL switch on the lid should disable the HV system when the lid is removed, but always follow the vehicle electrical isolation procedure and verify that no voltage is present before beginning work. The HVJB contains the fast charge contactors, which are controlled by the master charger, that close to create a direct link between the charge port and the HV bus. The contactors are normally open, and only close while supercharging to allow current to flow directly to the HV Battery. The HVJB contains 3 fuses: a 50A fuse on the DC positive output from each charger, and one 100A fuse on the DC positive supply circuit that goes to the DC-DC converter. If no slave charger is installed, the connectors are inserted into a holding fixture, and the vehicle harness connector is plugged into the dummy connector on the side of the HVJB, so that the HVIL and CAN circuits are complete.
     
  15. Rocky_H

    Rocky_H Active Member

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    You're being unintentionally misleading because there is a fact you seem unaware of.
    I see from your 3,000+ comment count that you probably have one of the older Teslas, so that is the paradigm you are in. On the older cars, the high voltage junction box was a separate piece of hardware from the onboard charger, and your statements would be correct about them being unrelated. But with the 2016 facelift refresh, when they reworked the charging system, they combined those into one unit, so the HVJB is a piece inside the onboard charger, so to fix a high voltage junction box problem, that does mean replacing the onboard charger.
     
    • Informative x 1
  16. N..8

    N..8 Member

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    Rocky, Good post. Although even when the HVJB was a separate box the Chargers sent a switching signal to the Fast Charger Contacts inside the HVJB to close them to allow the DC Voltage to the batteries. Without the Fast Charger Contacts the Charger Port would always have 350 or 400 volts present.
     
  17. Daniellane

    Daniellane Active Member

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    I haven’t read all responses. I literally had this exact issue with my previous Model S 90D while out of town on my first road trip in the first week of ownership last year. I had to use ChargePoint and a 110 outlet to get home. They replaced the onboard 72amp Charger and all was good. At the time it was explained to me that even though supercharging is DC and bypasses the actual AC to DC onboard charger, The circuitry on the charger does provide power management during supercharging. I can only assume this is somehow independent from the power management for AC to DC charging, since it also worked in my case.
     
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  18. David99

    David99 Active Member

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    I learned something new. Very poor design choice then IMHO. The chargers work perfectly fine themselves, yet when they are not needed (DC charging) they fail to just flip a simple switch to be bypassed. That has to one of the worst designs I have seen.
     
  19. Daniellane

    Daniellane Active Member

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    As I understand it, Tesla Power Management is elegant and pretty complex.
    Miles above competition.
    System is constantly monitoring battery temperatures in multiple regions of the pack and contralto controling temperature regulation and rate of charge to preserve health of pack. It’s fantastic that only one type of charging is still functional when the other is not. Otherwise I would have been stuck.
     
  20. David99

    David99 Active Member

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    I'm not talking about the BMS. I'm talking about the fact that a perfectly working AC charger has to be replaced and wasted because of a switching feature that is completely independent from AC charging.
     

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