Hi - I am considering buying a 22kW X22 charger. I have a 3 phase grid connection and a 6 kW enphase solar system. The enphase system only seems to be feeding one of the three phases.
Will the X22 be able to provide solar only, solar + 3 phase grid top up and 3 phase grid only charging?
thanks.
Hi there.
The short answer is yes, but there’s a bit of nuance in there which means you may also need a longer answer…!
First it’s worth mentioning that your car may only charge on one phase - many new ones will charge off all three but some don’t. And almost all three-phase ones will still only charge at 11kW rather than the full 22kW, so bear that in mind too.
The X22 will monitor all three phases, and will look at the net export across all three to decide how quickly to charge under “solar-only” mode. So if you export 6kW on one phase and 0kW on the other two, then it will charge at 6kW to balance that out. This is done by supplying 2kW to the car on each phase (phases have to remain balanced to the car). So in a net calculation you will consume your 6kW of solar, but under the hood there will technically be import on some phases and export on others.
If you want to consume from the solar and grid then you can charge at full speed during the day. The maths for your power bill will cause you pay for just the proportion of the energy which came from the grid.
Finally grid only charging can occur whenever there’s no surplus solar beyond your home consumption. If there is a surplus then the only way to “prevent” it from going into the car is to stop charging.
Having said all of this, my gut feel is that the best option for you would actually be an X7 charger because your solar setup is less than 7kW so it will never need the speed that an X22 can deliver. The X7 can monitor all three phases and ensure you match the net import / export, even though it will only charge on one phase. The only reason to get an X22 would be if you think you will occasionally need to charge at higher speeds from the grid (and even then you may well be limited to 11kW by your vehicle).
If you choose this option then mention to our sales team that you have a three-phase home so that they can ensure we send three clamps to measure all three phases (by default the X7 only comes with one to measure one phase).
Kind regards,
Tom
Great - thanks Tom for the comprehensive explanation. Good to know that it will work.
The car is max 11kW but I expect I will need to charge quickly from time to time so will go with the X22 I think.
To clarify a bit further, what does the x22 do in the following situations?
It will depend on how it is configured, and I’ve assumed that the charger L1 input is wired to the phase which has the solar on it.
If the “Use three phase switching” toggle is switched ON, and the schedule says Solar
If toggle is off, schedule says Solar
If toggle is on OR off, schedule says Charge
If you are in NZ and only have solar on one phase, you are likely best off using a single phase charger wired into the phase with solar, unless you think it’s very likely you’ll need to charge at 22kW much of the time.
Tom
If instead the solar is distributed across 3 phases and at times the generation is low, maybe 0.5 kW per phase. Can the x22 aggregate the phases to provide enough single phase load to the car to charge it or is there a minimum per phase load that must be achieved?
It’s not possible to offer less than 6A to the car (~1.5kW), so when there is 0.5kW per phase, the “three phase switching” charger will offer 1.5kW on one phase and 0 on the others, while the “not three phase switching” one will offer nothing.
This 1.5kW minimum limit is due to the signalling standard used between charger and car.
Tom
Coming back to this question because of another response about 3 phase handling.
To me this suggests that the charger will take 0.5kW from each phase and offer 1.5kW to the car on one phase. Extending this, the charger could take 3kW, 2kW, 1kW on each phase respectively and could offer 2kW on each phase to the car. These have the charger being able to move power between phases to send the car what’s appropriate.
The other explanation that seemed to be implied elsewhere that when the charger sees 0.5kW on each phase it chooses to pull 1.5kW from one of the phases which it uses to send to the car. This alternative has the inverter moving power between phases to meet what the charger is drawing.
Which of these explanations describes the charger’s behaviour? Can it move loads between phases or relies on the inverter to match what it’s drawing?
The charger can’t “move” power from one phase to another, and indeed all it is doing is connecting the wires through to the car and telling the car the maximum it can draw. So when it sees 0.5 kW on all three phases, it connects one live wire to the car and signals a maximum of 1.5 kW to be drawn on that wire. The other two live wires remain disconnected.
Some (but not all) inverters can move power between phases. So when they see uneven draw on the home they can alter their output to balance the phases. So in the above scenario the home would move from exporting 0.5 kW on each phase, to zero on each phase, with the excess from phase 2&3 moved across to balance the extra load on phase 1.
Hope that all makes sense.
Tom