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What does a EV charging point actually do?

Harry Macdonald

I have bought a 2nd hand Nissan leaf and have been happily charging it slowly from a 13A socket (fed by solar panels) for 6 months using the "granny lead" that comes with the car.

Yesterday, when I turned it on, the READY and CHARGE light flashed about once per second, as did the lights on the dashboard, and there was a click each time from the unit. The manual does not list this combination as indicative of anything.

This lead me to wonder what the "charging unit" actually does, It lists its input and output as 250V ac so it clearly is not a transformer/ rectifier. If it is a protective relay measuring neutral earth voltage, then maybe the ON / OFF is caused by something happening to the voltage in the house?

I have not found any information on the internet as to what is inside these units.

Parents
  • 0

    Thank you for all the helpful replies.

    Yesterday my "granny lead" was cycling on and off at about one cycle per second, with the Power and Supply lights going on and off and the Fault light staying off. Today, it is behaving itself.

    I was wondering if it could be detecting a high neutral - earth voltage at my house and turning off, which reduced the load and the voltage and turned back on again?

    I can't think of anything else that would cause it to cycle in this way, but I am not convinced by my own idea either.

Reply
  • 0

    Thank you for all the helpful replies.

    Yesterday my "granny lead" was cycling on and off at about one cycle per second, with the Power and Supply lights going on and off and the Fault light staying off. Today, it is behaving itself.

    I was wondering if it could be detecting a high neutral - earth voltage at my house and turning off, which reduced the load and the voltage and turned back on again?

    I can't think of anything else that would cause it to cycle in this way, but I am not convinced by my own idea either.

Children
  • 0 in reply to Harry Macdonald

    well if you suspect a fault, you could monitor the earth neutral voltage. and then plug in a kettle or something. Don't overlook simple under voltage drop out either.

  • 0 in reply to Harry Macdonald

    I think you are referring to monitoring live neutral voltage to help detect open pen faults, in an open pen fault the neutral and earth connection will raise to the same voltage. I don't believe the type 2 granny chargers support this feature, due to this and risk of overheating the socket and supply circuit they are not recommended for regular use.

    Under voltage implies an open pen issue. But it's more common to have an over voltage issue with solar because the grid wasn't designed to deal with solar generation being fed back in, quite often this results in high supply voltages, above 253V. If this is the issue it's time to ask the DNO to reduce the supply voltage.

    Cutting in and out could also be because of overheating or maybe a poor connection on one of the control pins?

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