Re: How to get 240V split phase for off-grid
In general inverters not designed to be "stacked" won't; there's no way to synchronize the frequency. Using an autotransformer is best.
But back-driving a grid tie inverter from an off grid one has more than its fair share of problems too. There's more than one thread about it on the forum. Synchronization troubles, over-powering problems, et cetera. Some have done it with generators too. It's also likely to void any warranty as it is clearly not "intended use".
Maybe you want to look into the new Xantrex 600 Volt charge controller and a small, stand-alone emergency off-grid set-up. Still cheaper to use a gen for emergency power.
1220 Watts of PV, OB MX60, 232 Amp hrs, OB 3524, Honda eu2000.
Ohm's Law: Amps = Volts / Ohms
Power Formula: Watts = Volts * Amps