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Thread: 3 phase supply, single phase inverter

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    3 phase supply, single phase inverter

    Hello

    With regards to a 3 phase house how does one go about installing an inverter which is single phase...

    I may be quoting a job for solar but competing against a quote for a single phase inverter and now wondering how does one do it.

    Do you make the whole house single phase ?

    If using the Sunsynk the excess solar feeds back to the non essential laods. But if those laods are on another phase then you can't.

    So do you make the whole house single phase ? If so what about the meter for when you on the grid and it's only pulling from one phase ?



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    Also keen to know.
    When I installed my gennie I bridged the 3 phases in the switchover box so the single phase gen supplies all 3 phases

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    Dylboy (30-Jun-22)

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    Diamond Member Justloadit's Avatar
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    I changed my house from 3 phase to single phase. There was no advantageous reason to maintain the three phase. Made the genny and inverter easier and cheaper to install, and take advantage of the back feed.
    Victor - Knowledge is a blessing or a curse, your current circumstances make you decide!
    Solar pumping, Solar Geyser & Solar Security lighting solutions - www.microsolve.co.za

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    Dylboy (30-Jun-22)

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    Ah nice.

    I think all is fine to make it single phase. But only thing back of mind is the billing and phase balance of Eskom and there may be penalty fees for doing so.

    But if it's been done and no adverse effects of that sort then I think all fine.


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    Platinum Member Derlyn's Avatar
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    @justloadit. Evening brother.
    Wracking my coconut 😁😁

    Please explain to this sparky what you mean by taking advantage of the backfeed.

    Thanks .. Derek

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    Quote Originally Posted by Derlyn View Post
    @justloadit. Evening brother.
    Wracking my coconut 😁😁

    Please explain to this sparky what you mean by taking advantage of the backfeed.

    Thanks .. Derek
    Hi Derek,

    If you use the Sunsync or the Deye, and you rewire your DB into essential and non essential loads, where essential loads are fed through the inverter, then during the day if there is excess solar energy, that means that the batteries are fully charged, and the essential loads are drawing less energy than than is available from solar, then using the installed CT just after the DB incoming isolator, the inverter then feeds the excess available energy back into the non essential loads to reduce the energy from the grid to almost null if there is an over supply of solar energy..

    Its almost like having the inverter on the input of the DB, but not requiring to size the inverter for the full DB load.
    I think this is called backfeed.
    Victor - Knowledge is a blessing or a curse, your current circumstances make you decide!
    Solar pumping, Solar Geyser & Solar Security lighting solutions - www.microsolve.co.za

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    GCE (01-Jul-22)

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    @Justloadit
    Thanks brother. Neat. So the more panels you have, the better, always.

    I'm having loads of fun with my teeny weeny setup. This weekend I'm installing 3 analogue ammeters. Amps from panels. Charging amps to batteries. Load amps.

    This will help me understand what is happening in real time without me having to guess.

    Cheers.

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    Diamond Member Justloadit's Avatar
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    Quote Originally Posted by Derlyn View Post
    @Justloadit
    Thanks brother. Neat. So the more panels you have, the better, always.

    I'm having loads of fun with my teeny weeny setup. This weekend I'm installing 3 analogue ammeters. Amps from panels. Charging amps to batteries. Load amps.

    This will help me understand what is happening in real time without me having to guess.

    Cheers.
    Get these Digital Panel Meters from Mantech, I believe they are now in Port Elizabeth.
    Go for the ones with an external shunt, and the shunt direction can be for charge current, and load current.
    Just take note, there is a bad design here, do not switch the meters on with out the Shunt connected, else it damages the current measurement circuit.
    They can go up to 30V DC direct.
    In the case that you need higher voltages, and you are not scared to add a few capacitors to a module, then you can use this SMPS Module to do the meter supply directly off your source, alternatively you can use a small AC to DC PSU.
    Victor - Knowledge is a blessing or a curse, your current circumstances make you decide!
    Solar pumping, Solar Geyser & Solar Security lighting solutions - www.microsolve.co.za

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    Quote Originally Posted by Justloadit View Post
    Hi Derek,

    If you use the Sunsync or the Deye, and you rewire your DB into essential and non essential loads, where essential loads are fed through the inverter, then during the day if there is excess solar energy, that means that the batteries are fully charged, and the essential loads are drawing less energy than than is available from solar, then using the installed CT just after the DB incoming isolator, the inverter then feeds the excess available energy back into the non essential loads to reduce the energy from the grid to almost null if there is an over supply of solar energy..

    Its almost like having the inverter on the input of the DB, but not requiring to size the inverter for the full DB load.
    I think this is called backfeed.
    Well explained explanation of the use on a true Hybrid - Going to steal it to use

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    Justloadit (01-Jul-22)

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    Just be aware of the inverter full feedback load capability of the inverter. If I recall an 8 KVA can feedback a max of 12KVA. This is where the supply(input/mains) wiring calculations to the inverter is important.

    The way I understand it works, if you install a 8000 watt unit (around 35 amps) then the unit can feedback around 12000 watts (50 amps)

    If you install a 4 or 6 mm wire you are going to experience overheating on the cabling. You would need to install at least 10 mm wiring to the inverter input.

    The output/UPS/essential or whatever you wan to call it, will only require a 6 mm wire.

    Talking Sunsynk, you then have the aux terminal which can be assigned to be used as an output or generator connection.

    I cant wait to get my demo so I can start tinkering.

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