[vteco]

Well redpoint5, the proof of the pudding will be in the actual running.

In theory the ratings of these components can provide 500 watts of house power, and your battery/ inverter method can absorb some degree of surge current and also provide inverter rated wattage above 500, depending on the batteries' capacity and usable discharge rate, and on sufficient wire sizes to handle the battery current. (Also you definitely need a transfer switch to ensure power line safety when testing a real house circuit.)

If demand, or the demand period, or any other cause exceeds those ratings or capacities, or the wiring is insufficient, one or more of those components will fail.

The two you don't want to fail most are the battery wiring, and the transfer isolation. The others may simply brown out or not work.

Be aware that some appliances don't tolerate low voltages well or altered AC frequency or waveform, which can happen if a source component like an inverter is overloaded.

I would like to see you try it, I'm not a nay sayer, but I would suggest gradually adding circuits while testing to ramp up slowly to your target power. And trying only resistive loads to start. Those are getting harder to find at least in the house circuit with the demise of the incandescent bulb. But I'm sure you could rig up a non house test circuit.

An electric coffee maker (if not too smart an appliance) can provide a test of an excess load, if you're already running a test circuit with incandescents at 500 watts.

If that works out, maybe run a small shop vac to test motor start and inductive load. Relatively inexpensive, and unlikely to burn out. Not like a refigerator.