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Tesla Wall Connector defaulting to 16A charge

Discussion in 'The UK and Ireland' started by ACarneiro, Sep 21, 2019.

  1. ACarneiro

    ACarneiro Active Member

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    Dear all: wondering if anyone has a similar problem or any ideas on how to fix this.

    The problem:
    My car seems to intermittently (not always and no discernible pattern) charge at 16A instead of 32A from its Tesla Wall connector.

    The setup:
    The house has two all connectors (one for a BMW i3 which reliably charges at 32A every time) and there’s is a comms cable joining the two (in case I want to load share but not sure the sparkies actually connected it).
    My M3 is setup to start charging at 0130 (when cheap tariff starts).
    Occasionally I will wake up in the middle of the night to see it drawing only 16A. If I use the app to stop charging and start again, it’ll then start drawing the 32A.

    This is a problem because I commute 100 miles every day and leave home around 0515 so only really have 4 hours of charge time. If the charging rate is only 16A I won’t be able to charge enough to replenish the previous day’s use.


    Has anyone seen a problem like this? Any suggestions on what to do?
     
  2. WannabeOwner

    WannabeOwner Well-Known Member

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    Hmmm ... not sure about that bit.

    You can "dial down" the AMPS from the dashboard and that location is remembered (GPS). So if you delibrately dial it back up again it should stay there (unless something senses a problem with the circuit.

    Is the voltage dropping maybe? (If you have TeslaFi you can see that (Menu = Help : Raw data - you may have to EDIT LAYOUT and change one of the existing columns to CHARGER VOLTAGE, but you can use EDIT LAYOUT after-the-fact). Also "Charge Current Request" - mine sits at 16 until charging starts, and then it increases to 32 ... and when charging is done it drops back to 16.
     
  3. Rooster6655

    Rooster6655 Active Member

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    Had a similar issue with a public charger, every time it went to 32A initially then it would stop charging but if I change it to 30A it works fine, I assume it does this in the day time also, so perhaps try lowering the amperage...
     
    • Like x 1
  4. ACarneiro

    ACarneiro Active Member

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    Voltage is absolutely fine, never saw it less than 230V even when both cars are charging.

    It doesn’t stop charging, either. It simply defaults to 16A.
    Annoying if I have to wake up at 01:30 every day to check I’m getting enough juice...
     
  5. WannabeOwner

    WannabeOwner Well-Known Member

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    Might be worth checking TeslaFi to see at what point the AMPs drop ... my thought is that such info could help a Sparky figure out if there is a problem at the outset, or only after everything has started to "strain" a bit
     
  6. NorfolkMustard

    NorfolkMustard Active Member

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    Do you perhaps have other stuff coming on in the house overnight - immersion heater etc, that could cause the charger to reduce its draw
     
  7. VanillaAir_UK

    VanillaAir_UK Moderator UK and Ireland

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    #7 VanillaAir_UK, Sep 21, 2019
    Last edited: Sep 21, 2019
    TWC is either load share or fixed output - its set via internal rotary switch and, in case of load share, via interconnect, one as master, the other slave.

    So you need to be ether one or other.

    If load share, the master will take the bulk of the charge, the slave will take the remainder. Sounds like Tesla might be slave so maybe worth swapping which charger each car uses, to see if things change. My uneducated guess is that i3 is on Master, Tesla on slave, so charge profile of i3 dictates what Tesla would draw. Makes even more sense if TWC is configured for >32A charging, but doubt that is the case unless you are 3phase.

    But you probably knew all that.
     
    • Informative x 2
  8. DaveW

    DaveW Active Member

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    My car is defaulting to 16A too, even when I set it to 32A and schedule a charge it often drops to 16A, happened this morning, despite leaving the ‘ready to charge’ screen at 32A.

    I posted about it today on the TOGUK group, seems we are not alone with this issue!
     
  9. booyaka76

    booyaka76 Member

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    weirdly - I'm the same - just home and wanted to test my new Rolec charger installed yesterday with my New SR+ picked up today.

    Starts at 32A but then drops off to 16A as well - this is despite car showing 32A max etc.......
     
  10. LEE3

    LEE3 Member

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    I am having this happen this evening and have just increased it to 25amp from the touch screen but it’s still only charging to 17amps.
     
  11. LEE3

    LEE3 Member

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    Just did a search and this can apparently happen if the charge plug is not inserted correctly. It will still charge but at a reduced rate. Worth a try.
     
  12. ACarneiro

    ACarneiro Active Member

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    Thank you for your comprehensive answer

    Yes, I suspect it may be related to the Master/Slave setup. I’ll have to open them up and see what the sparkies did... I assumed that, once the master started drawing less power, the space would then take over and go full pelt

    Also, I have often seen both cars drawing the full 32A each so I’m not entirely convinced it’s a simple load sharing problem...

    Thank you again. :)
     
  13. LEE3

    LEE3 Member

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    Fixed ! Just unplugged and reattached and it’s now up to the max.
     
    • Like x 1
  14. booyaka76

    booyaka76 Member

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    Check it again in 5/10 minutes - let me know - mine started at 32A then dropped off after 5/10 minutes to 16A
     
  15. animorph

    animorph Active Member

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    For OP, we have Tesla Wall Connectors sharing a 100A circuit, so 80A to the cars is shared. If only one car is charging we usually get a full 72A (X) or 48A (3). With both cars charging they simply split the available current, 40A to both. For a while the Wall Connectors would only allow 40A if a second car was plugged in, even if it wasn't charging. I think a firmware update might have fixed that a few months ago.

    It seems like your two TWC's are either charging two cars at once or acting as if they were. An exact fit to the symptoms if this is a 40A shared circuit. Try disconnecting the i3 before charging the the 3.

    The TWC will reduce the current if it senses a voltage drop of something like >10V between starting at 0A and charging at 32A. But I haven't read of a 32A -> 16A reduction in that case.
     
  16. LEE3

    LEE3 Member

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    Mine finished charging at the max available.
     
  17. booyaka76

    booyaka76 Member

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    cool - I'll try again tomorrow and see - got plenty of juice in the car for the next few days
     

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