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Wall Connector powered by 13A wall socket

Discussion in 'Hong Kong' started by ivan3721, Aug 24, 2016.

  1. ivan3721

    ivan3721 Member

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    I am currently renting my place so I have no intention of spending thousands of dollars on electrical work.

    What I plan to do is wire up the Wall Connector to a regular 13A plug, and simply plug it into a wall socket (all waterproof, of course). I will also set the Wall Connector to charge at 13A.

    Here is the interesting bit: A Tesla recommended electrician told me that the Wall Connector setting of 10A or 16A works, but the 13A setting does NOT work. He said Tesla told him so.

    Any idea what this is all about? Anyone sees any problem with this setup otherwise?
     
  2. garethmchau

    garethmchau Member

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    Only thing wrong with it is that it would be dog slow. You'll get max 5km/h means that you'll get 50kms of charge parked overnight for 10 hours which is almost no point. Might as well park somewhere near work which has a type 2 charger like Star Ferry car park which gives you 32km/h and all paid for by the govt too.
     
  3. ivan3721

    ivan3721 Member

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    Thanks, I have taken this into consideration.

    Just wondering if anyone has this setup and does it work? (slow charge rate aside)
     
  4. ediot

    ediot Member

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    if you're setting it at 16A you may want to check that wiring from your main circuit board to your socket can support it, since a constant 16A draw may have heating issues etc - best to check with your qualified electrician. you may not even need a "Tesla endorsed" electrician BTW, the wall charger install manual makes things very clear, and is easy for any qualified electricians to follow it step by step.

    charging your car at 10A or 16A at home is painfully slow, and you'll encounter some moments where you get home late, the car charge is low, and the next morning you need to be out and about the whole day. The charger wouldn't provide enough charge, unless you do what some owners do now - pop round to a supercharger to fill it up like a slow gas station up to 80% or so (supercharging will start slowing down then), and top it up to 90% at home with your trickle charge

    is your waterproof socket already in place? if not, pulling a 40A copper wire from the MCB to give proper charge MAY still make sense, since it's a simple copper wire from MCB to your charger, and when you move, you can take off the wire and bring it with you to your new place as well.
     
  5. markwj

    markwj Moderator, Asia Pacific

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    Running that BS1363 at 13A for extended periods of time will probably melt it and/or the plug on the EVSE. If the wiring behind is not modern and well laid, it might also damage that. That socket is really designed for boiling kettles for a couple of minutes, not 13A continuous draw all night long. The socket is not rated for 16A and that should never be done.

    In general, the recommendation is to limit to 10A. Lots of roadster owners have been doing that for 5+ years here, without much issue.
     
    • Like x 1
  6. jsiu

    jsiu Member

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    All depend on your daily mileage. I only travel 60-70km per day. 10A charging via 13A socket implies a rate of 10km/hr. An overnight charging has already been more than sufficient to top up the battery. In the circumstances, only a proper well-built 13A water proof socket will be good enough for me. In fact, I have never used SC and most of my charging is either from 13A socket or 32A medium charger. To conclude, if you simply travel around say 70-80km per day and you are able to charge your Model S every night, even a well built properly constructed 13A socket will be good enough.
     
  7. jsiu

    jsiu Member

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    I think we have to change the mind set of 'tank-up'. For ICE, you only go to petrol station when the tank is empty. For EV, the practice should be 'plug and charge' whenever and wherever there is a charger. No matter fast or slow, when there is a charger, just 'plug and charge'.
     
    • Like x 1
  8. garethmchau

    garethmchau Member

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    are you sure you get 10km/hr from a 13A socket though?? When I first got my car, I tried in car park of Science Park and it was a dog slow 5km/hr which was totally not worth so I unplugged and went up to queue at the Supercharger...
     
  9. jsiu

    jsiu Member

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    100% sure, 10A x 220V = 2.2Kw, my 70d consumes 1 KwHr for every 5km. 2.2Kwhr x 5km = about 10Km. This in fact shown on my Tesla Iphone App at 10km/hr. If you cannot get 10km when charging at 220V @10A, I would suggest you contact service centre. Or you have a bad 13 A cable. Sometimes, you get slower if the AC voltage drops below 220V.
     
    • Like x 1
  10. ivan3721

    ivan3721 Member

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    Thanks all for your response. But I guess I'm not clear on my question.

    The tesla appointed electrician told me that although the Wall Connector has a 13A setting, it does not work because the vehicle does not recognise that setting and will not charge.

    My question: does anyone run their Wall Connector at 13A and whether it works?
     
  11. mattse

    mattse Member

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    I guess there may not be anyone using the wall connector at 13A, you may need to email Tesla about your situation and ask them for a specific reply

    I thought of one way to get around the problem (I am no electrician so it's purely out of my imagination), have your electrician set the wall connector with 16A setting, and then you limit the charging current to 13A in your car. So the wall connector and the car will "think" they are running on a 16A track but only using 13A all the time (while they are in fact running on a 13A track)

    But the most important issue here is, as a few members have pointed out, the wiring behind that 13A plug. If it's designed for (up to) 13A only, it's not wise to draw a 13A current from it for extended period, otherwise it will overheat. And you won't have any protection from the circuit breaker as there is no overcurrent (13A is the permitted current size).

    13A vs 10A means only a less than 3 km/hr charging rate difference. This difference will be very close to 3 km/hr if you have a constant 220V current, which is not common in HK 13A plug. The voltage usually fluctuates around (and below) 220V. You won't want to risk your car and all the trouble that follows a fire from overheat for this small difference.
     
    • Informative x 1
  12. ivan3721

    ivan3721 Member

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    Thanks mattse. I agree that it'd be wise to use 10A instead of 13A.

    I found that behind that 13A wall socket is a 20A circuit breaker which is shared with several ceiling lights and a washing machine. Does that mean the wiring behind the socket *should* take at least 20A, since the breaker is 20A?

    Anyway, to be safe, I will set it to 10A for now.
     
  13. markwj

    markwj Moderator, Asia Pacific

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    Unfortunately, that means it doesn't follow the standard for wiring EV charging in Hong Kong.

    http://www.emsd.gov.hk/filemanager/en/content_444/Charging_Facilities_Electric_Vehicles.pdf
    That is really the concern with using general house wiring for EV charging - the cabling behind the plug may not be designed for it. Of concern in your case is running the washing machine at the same time as EV charging.

    Anyway, in normal case the limiting factor is the socket itself (13A for short periods). Setting to 10A _should_ be ok, but I wouldn't run the washing machine at the same time.
     
  14. Jason90

    Jason90 Member

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    Your main circuit board should have a few spare slots, and, as suggested above, you could ask your electrician to run a separate cable for your charger - I can't imagine that would be a very large additional fee above the existing charge for wiring in your charger, and far cheaper than burning down your building and, if you survive the fire, facing the legal consequences....
    I agree that 10A is enough - you will get 9 - 10 Km range per hour of charging (that's what I get with my 'old' P85), which is sufficient unless you do unusually high mileage.
    My wife has put 38,000 Km on it in a little under two years, mostly with 13A sockets charging at 10A.
    Agree you should charge opportunistically whenever you park - although it is getting harder to find available chargers in car parks as there are now so many EVs on the road.
     
  15. ivan3721

    ivan3721 Member

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    Yes, my plan is to charge at 10A now.

    But why would charging at 10A using an existing socket with a 20A circuit breaker (albeit shared with a washer) cause a fire? Isn't that exactly what a circuit breaker prevents?
     
  16. Optic

    Optic Member

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    If the circuit breaker fail to deploy at 20A while your wire harness is only rated for 16a, it can cause a fire. It is like you want to drive into a wall at 60km/hr and assuming the airbags will save you. Most likely yes, but the circuit breaker needs to deploy properly.
     
  17. jsiu

    jsiu Member

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    This will depend on the current capacity of the wiring behind the socket. Assuming the wiring behind the socket can only support 13A, your charger takes 10A and the washing machine takes 5A, then the total is 10+5 = 15A which is higher than the capacity of 13A. Under this situation, the wiring will be over heat and on fire before the 20A circuit breaker functions.
     
  18. mattse

    mattse Member

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    Yes or No. The one who laid the wiring may put those good enough for 20A, or just good enough for 13A (which is cheaper and can cover most routine household use). You need an electrician to look into that. And since the circuit should be connected in parallel rather than in series, it's most likely that all the wiring from the circuit breaker is (up to) 13A only while the circuit breaker itself is good for 20A

    (In case you are not familiar with parallel or series circuit stuff)
    Think of the roads connected to the cross harbour tunnels, most of them are 2 - 3 lanes (some even are 1 lane only), but when you get close to the toll gates, you have many more lanes.

    The roads connected to the tunnel are your wiring. The toll area is your circuit breaker. You may have many small roads (up to 13A) connected to the toll area (your 20A circuit breaker).

    I guess you are referring to the comment from Mark about not running the washing machine at the same time. The Wall Connector and the washing machine use "two different sockets" in our eyes, but as jsju has pointed out, they may be sharing the same wiring behind those two sockets. You leave a good margin of safety running the Wall Connector at 10A, and the washing machine will take away that margin without you knowing it (if both your car and washing machines are drawing power at the same time)

    If your Wall Connector and your washing machine are running on completely different wiring, let's say they run in opposite directions, it still could not eliminate the possibility of them sharing some common path before parting.

    Let's put it in another way using the cross harbour tunnel analogy. Question is are the "Wall Connector road train" and "washing machine truck" using the same road? If so, since both are very big, big vehicles, you will have traffic jam (overheat) in that particular road (wiring) while the toll area has normal traffic (total current still under 20A). When you look at the traffic at the toll gates, we are having a beautiful day (circuit breaker won't be triggered). When you look at the traffic in one of the roads, we may be heading into a disaster.

    Options are:
    1) ask your electrician, he will know if the Wall Connector and washing machine are sharing any wiring or not at all; or
    (As suggested above)
    2) build a new road for the "Wall Connector road truck" (separate wiring); or
    3) while the Wall Connector is in use, stop all other major user, i.e. the washing machine
     

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