Most off-grid houses (and small boats) use DC coupling for the electrical system where power sources (PV panels, wind or water turbines, alternators, generators, etc) feed DC electricity to the battery via a charge controller. The DC from the battery is then either used as such or converted via an inverter to AC at normal household voltages for use.

A few, though, use AC coupling where the power sources feed their output as AC into the “mains” wiring to form a sort of mini-grid with the power flowing in and out of the batteries via an appropriate inverter which also acts as a charger.

I'd assumed I'd just use DC coupling for my house but I'm gradually coming round to the idea of using mostly AC coupling. I'm not really clear about some of the details so here's a snapshot of my thinking to help make things a bit more concrete.