1 phase, 2 phase, 3 phase charging

[Tinbum1]

Some cars now allow the charging to be changed between 1 phase, 2 phase or 3 phase charging while the car is actually being charged without having to stop charging.

When charging from PV there is not always enough available PV power to run all 3 phases so;

The OpenEVSE has 3 outputs that it controls. Relay1, Relay2 and AC relay.

Could a facility be added so that;
The AC relay output controls a 4 pole relay that would supply 3 phase to the car as normal.
Relay1 could control, separately, a dc controlled Solid state relay to switch on or off Phase 2. (Wired in series to the 4 pole relay output.)
Relay2 could control, separately, a dc controlled Solid state relay to switch on or off Phase 3. (Wired in series to the 4 pole relay output.)

Both DC1 and DC2 would be controlled over MQTT or RAPI, or even in the firmware. It would also require the state of Relay1 and Relay2 to alter the kWh being recorded from the simple 3 x single phase current currently used.

Chargers like the Myenergi Zappi 22kW have this feature.

[gangajain]

I think this could be a useful feature, especially for installations where the available power changes throughout the day.

Using a solid state relay for switching Phase 2 and Phase 3 seems like a practical approach since it allows fast and reliable control without frequent mechanical wear. The firmware would just need to ensure that phase switching only happens under safe conditions and that the charging current is adjusted before any transition.

It would also be important to keep the energy measurement synchronized with the active phases so that power and kWh reporting remain accurate. If implemented correctly, this could make automatic 1-phase to 3-phase switching much more efficient for PV-based charging systems.

[Tinbum1]

There does seem to be some movement on this, but not quite as I envisaged. I wanted the ability to change the number of phases being used as the car was in the process of charging. It seems, as I understand, that the proposed changes only do it at boot.
I have done some work on this myself and am using it to charge my Skoda and it's working really well. One thing I have found is that the car does not like an SSR due to the leak voltage. I tried a resistor across the output but that didn't work. Best to stick with a contactor. I have use a 4 pole to switch all phases and then added 2 other contactors on its output to switch off phase 2 and or 3.