Do I need a smart phase controller with a Multi plus 2
If you are installing the Multiplus II 2x120 then this is a single inverter that works off of L1 only. L2 is passed through unmodified. When inverting, L1 and L2 out are in phase and fed from the inverter. Shore power is disconnected.
If you plan to connect two of the standard MP II 3000 models, they need to be configured for split-phase operation with 180 degrees phase shift and "floating phase". Also turn off switch as a group so that when you provide 120 volt shore power one inverter will accept the incoming AC input and pass thru/charge the battery while the other inverts.
Devices that maintain phase relationship between legs are not required in either of these scenarios. But I'm guessing what a "smart phase controller" might be.
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