I believe it does have a mode where it will power loads with utility power first, then use panels and battery. However, it is not at all "grid tie" because it will not export power to the grid. If my recollection is correct, there is a max amperage that it will draw from the utility input. (I'm certain there's as max amperage it will draw from the utility input to charge the pack. I forget, but I want to say it's 30A.) Likewise, I think there is a mode that uses the grid input as a "boost" when the inverter is otherwise maxed out -- but I'm not sure.
In my case, where it is truly off-grid, I have leads for a gas generator connected to the utility input. One oddity is how the Growatt behaves when the generator is on. It's a pure sinewave inverter, and my generator is a pure sinewave output. Yet when the generator is running to charge the pack, the loads behave like they are connected to a modified sinewave inverter -- lights flicker, etc. I can't explain it, but it's decidedly annoying.
Nowadays it seems to me that grid tie no longer exactly means export to the grid. Electric companies started acting like they are being cheated and saying self generated power users are not paying their fair share. They started giving less credit for over generated power and started charging higher fees etc. In some areas its even worse. Also IMO it’s always been better to save excess power generated into a battery to use yourself rather than give it to the electric company for peanuts.
There is a few grid tie inverters out there that limit the production to only what the loads actually are. And allow excess power to be saved in a low voltage battery. They do this with CT clamps on the homes mains wires. Solark, outback, and SunG are the only ones that I found with this capability. The inverters will continue to supply full power when there’s surges (or constant load) above its max output (letting the utility supply the excess needed) like a grid tie inverter setup. They still allow for low voltage battery storage for excess pv power when there is more solar than loads are using like an offgrid inverter setup.
I’m not specifically referring to AC coupled systems. For example, my system uses a dc charge controller that goes to dc the batteries, which power the grid tie inverters that uses current transducers. I keep the utilities power (grid) for start up surges and occasional high loads. Besides that my electric bill is next to nothing. This way I don’t have to be so hard on the batteries. I saved a good chunk of change from not sizing the inverters and batteries for the surges and occasional high loads.Exactly, if you have a grid connection, then AC-coupled systems, as you are describing here are the future. You want the grid as a helper from a physical, but do not need it from a financial standpoint.