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EV Charger Solution Needed

Discussion in 'Electrics UK' started by Basinguy, 19 Sep 2021.

  1. Basinguy

    Basinguy

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    Hi All,

    I'm in the process of buying a PHEV car, but could do with some advice over the charging side.

    I've been looking at the mainstream charging points from the major suppliers who all quote about £500-600 to install a 7Kw charger (plus all the additions you know will be needed when they come and do their tut'ing), but as its only a PHEV with a 14KWh battery, charging from a 13A socket would only take 6h which is fine.
    Plus the fact that my overnight rate would only be 10p/Kwh cheaper, the charging point would take about 15 years to even break even due to the decreased electricity cost (4h of charging at cheaper rate and 2 hours at normal rate) by which time I'm sure it'll be obsolete or knackered.

    So … for now at least, my plan is to have a 13A socket installed outside, which I can plug the car into using a 2.3Kw mode 2 cable. The car can be setup to only charge during the cheaper hours.

    However, how do I stop some unwieldly neighbour coming and stealing my leccy?
    I've searched for lockable boxes but found nowt that looks suitable, does such a thing even exist?
    The car has a 'lock' for the cable on it's end, but nothing for the other!
     
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  3. flameport

    flameport

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    If that really is a problem, then have a switch inside the house which will turn the socket off when not required.

    Millions of homes have outdoor sockets and don't have a problem with electricity being stolen.
     
  4. Risteard

    Risteard

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    A granny lead shouldn't be considered as a permanent solution.
     
  5. Basinguy

    Basinguy

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    How come?
     
  6. Risteard

    Risteard

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    You will have a long duration substantial load which is liable to overheat the plug and socket-outlet.
     
  7. Basinguy

    Basinguy

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    Good point those 3pins probably aren't ideal for long term load.

    I Could rewire to a commando socket, that should be a more suitable long term
     
  8. ericmark

    ericmark

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    I did a google for child lockable sockets UK and got [​IMG]the link here there are also versions which lock down a lid, [​IMG] again link here and of course you can fit the socket in any box you want, as long as there are some holes for cooling.

    It seems odd that at the railway where I work there are loads of sockets like this [​IMG]put there for volunteers caravans etc. And in spite of being in view and easy to assess no one has been caught stealing electric from them, the EV charging points 22 kW we have had problems with, first 15 minutes is not charged for, and we have found people sitting there unplugging and plugging back in to get extra 15 minutes free.

    What is more of a problem is fitting a socket where the item using the socket needs an earth, outside when the supply is TN-C-S.

    How much it is a real problem not so sure, I am sure however you will get more comments, but there are two major problems with EV charging.
    1) RCD protection, due to having a battery which can allow DC under fault conditions to be superimposed on the AC supply, which can freeze the standard type A or AC RCD either there needs to be a detector which monitors if there is DC over 6 mA and will auto disconnect if there is, or the RCD needs to be type B, and you can't take the feed from any existing RCD's as it could freeze them. It does not matter which type of supply this is still a problem.
    2) With a TN-C-S supply should the PEN be lost, there is a danger outside due to the DNO earth not being same voltage as real earth, could be 230 volt between the two, if this happens then the voltage will also vary outside limits, so the EV charging point is set to auto disconnect if the voltage is not between 207 to 253 volt, i.e. it fails safe. It not only disconnects the lives (line and neutral) but also the earth bonding.

    So to use a 13 amp or 16 amp socket you also need to have at least 2.7 meters from the home, and use an earth rod and convert to TT, and fit a type B RCD so by time you add the costs type B RCD around £250 and earth rods not expensive but likely need a paddies motorcycle to install them, plus testing, so likely will cost around the £400 mark to fit a 13 or 16 amp supply. DIY you will not have the meters required to test, so not really a DIY job.

    As @Risteard says the granny lead is for emergency use, the chance of some thing going wrong on the odd time you recharge from some ones house, is slim, but to do it every day, sods law it will at some point go wrong, and a risk assessment shows it is not the way forward.

    I do not agree that it may over heat, designed for 13 amp only using 10 amp, but I do agree should not be used on a regular basis.

    My EV's both use 13 amp sockets, and are charged in doors so the TN-C-S supply is not a problem, both chargers are class II so there is no earth connected anyway, one is 36 volt the other 48 volt, and they have some where around 12 Ah batteries, and I use a standard type AC RCBO, maybe it should be type A, but the ring final which they are plugged into is in the flat under the house, so the risk assessment I did shows very unlikely to be a problem, both EV's by law are limited to 250 watt on a continuous basis, so your 14 kWh battery seems huge when compared with the 300 Wh battery fitted to our Ebikes.

    I have looked at 10 amp chargers [​IMG] there is a box which clearly does something, maybe this does what is required to make it safe? What we need to know is what is in that box, and I don't know.
     
  9. AndyPRK

    AndyPRK

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    You could have a 16A timer inside the house to only turn it on during cheap hours + a bit more.

    if it were a switch you may forget and be really annoyed!

    https://www.ebay.co.uk/itm/293305356139

    but again the cost would be more than the cost of stolen electricity !
     
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  11. Basinguy

    Basinguy

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    Thanks for the comprehensive reply.

    What is concerning here is that selling a charger with a 13a plug on the end suggests it could be plugged in anywhere and nobody would be wiser of their earthing arrangements. Including me slinging the plug through the garage door and plugging it in.

    I have a TT system and a dedicated socket in the garage which the previous owners had fitted to connect their camper van hooked upto.
     
  12. SUNRAY

    SUNRAY

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    IF you decide to change the 13A plug to a 16A be very careful as it is extremely likely there are more than 3 wires and the colours tend to be very different to that expected.

    Edit; Apologies I've repliedto the wrong post but I'll leave as is.
     
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  13. Basinguy

    Basinguy

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    The current socket is a standard 2g 13a metal clad in the garage, wired in 2.5mm back to a dedicated 20mcb in the garage cu, only ever used it for the pressure washer :cool:

    I was hoping to just extend that circuit to an outdoor socket to make life a little easier.
     
  14. ericmark

    ericmark

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    So for you it seems yes you can use a granny lead, personally not worried about the RCD, we have worked for years without them, however do ensure the house and garage are not on same RCD. DC freezing the RCD supplying the house is clearly a problem.

    The problem as I see it is items offered for sale like this [​IMG]it has a socket and a RCBO why it has a RCBO fitted I really don't know, as the instructions say it must be fed from a type B RCD, see data sheet I think it is misleading where it says need a type B RCD and a type B RCBO is fitted, it does further down say the type B RCBO is a combination of two functions, a type B MCB and type AC RCD. Which seems daft as it also states you need "Type A RCD and appropriate equipment that provides disconnection of the supply in case of DC fault current above 6mA or Type B RCD" so type AC is no good.

    So in real terms the socket shown is an expensive bit of rubbish.

    The big question is if the garage if fed from the house RCD or its own? Also is the car to be charged in the garage, if charged inside the garage no problem with a TN-C-S supply, that is only a problem if charged outside.
     
  15. Basinguy

    Basinguy

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    So, the garage is supplied by a dedicated 32A RCBO on the house cu and 6mm T&E from the house to the garage.
    The garage then has its own small cu with 3 MCBs
    20a for sockets radial
    6a for lights
    20a for the 2g camper plug.

    The car would be outside, but plugged in either inside the garage on the camper plug or potentially an outdoor socket
     
  16. davelx

    davelx

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    Delete!
     
  17. davelx

    davelx

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    Your wish....

    IMG20210920091722.jpg IMG20210920091211.jpg IMG20210920091203.jpg


    Note the toroidal transformer around the incoming CPC. Also 3 chunky relays. If you look at the rear label, you will note that it has 30mA AC and 6mA DC IΔn protection.
     
    Last edited: 20 Sep 2021
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