I thought SUB/SBU meant it does NOT mix and does NOT do grid assist/peak shaving and does NOT have the necessary inverter control to achieve this. Just a transfer switch to lock out the grid vs the inverter
And when I say SUB/SBU I mean only one AC source can carry the load, with no blending. If the inverter cannot carry the load then the full grid can carry the load.
Otherwise, how the heck is everyone getting away with parallel operation?
However since these are inverter/chargers, when charging from grid the inverter hardware is connected albeit configured in charging mode