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MultiPlus II 3-phase selective passthru

Hello,

I have 3 MultiPlus II 48/5000 connected to the three phase grid. Most of my house is connected directly to the grid, and some circuits after the Multis for emergency power. ESS works flawlessly with an external grid meter. I run my own ESS logic in a python script, mode set to "external control".

I noticed that the three inverters always seem to switch on or off together. When the battery is empty and there is no PV power, all three switch to passthru mode. When the battery starts charging and there is enough solar yield the next day, the inverters switch back on.

What I'd like to do is switching 2 of the 3 Multis off selectively when demand is low. At night, power consumption is only around 250W, but with the 3 Multis running, the PV system alone uses around 80W, which significantly decreases efficiency. I read somewhere that this would only be possible with a fourth, small Inverter, but that seems unnecessary with the Multis having all the hardware built in.

I can set the grid setpoint to 0 for any of them or stop sending setpoints altogether, but that does not disable the inverter, as it still supplies power for critical loads. Would it be possible to make it go to passthru mode instead, switching the inverter off and only passing power from the other inverters?

I am allowed to do phase compensation via grid for up to 4.5kW, so only one inverter running at night would be enough to keep the total sum at 0, and lower the overall power consumption. When demand gets higher, I could start a second inverter, and finally the third.

Is there a way to achieve this? Have I missed something? Or is it just not within the firmwares capabilities to switch the inverters separately? They would not be off completely, just in passthru until needed again.

Multiplus-II
2 |3000

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