I have an off-grid system with PVs and Phoenix inverters C 12/2000 working in parallel. I would like to add a grid-tie inverter to the AC output of the Phoenix inverters to increase power. What I have learned so for from previous discussions is that this should work, Phoenix inverter is the same as MultiPlus just without AC input for the grid connection and can charge the batteries? Is this right? If yes, then the 1:1 rule applies.
So this setup will work only with grid-tie inverters that support frequency shifting. How can you know if a certain inverter has this feature? I can get Fuji FU-SUN 3kW inverter or FUJI Microinverter 2kW at great prices, but I don't know if they support frequency shifting.