Never mind. The manufacturer indicates that it can't be done. Even tho the unit is rated for 3500 Watts, I can only draw up to 15 Amps from any of the 4 outlets (not to exceed 29.2 total). I think it'll still work for my application. I prolly coulda saved some ching tho & got an 1800 with a single output.
Working the math: If I'm drawing 15A from the output of the inverter, it's drawing 168 Amps from the battery - that's sobering.