Small scale solar battery to grid transfer switch?

Hi all, new to this sub and solar in general.

I live in an apartment with a sunlit balcony and had the idea of doing a small scale solar project to save money on my electric bill and lessen my dependence on the electric grid.

I would get a battery and charge it with 400 or 800w panels. I want to know is it possible to have a solar system that can use the stored electricity generated from the battery, and automatically switch to the main line (grid) power when the battery inevitably depletes. I see transfer switches exists in homes in general, but the idea is for me to power a single large appliance on solar power as a main, but switch to grid power when the solar battery dies in a way that does not interrupt service, then switch back to solar when the battery is fully recharged. I would only be powering NEMA 5-15 plugs, so I want to avoid messing with the circuit breaker since this would be only powering one or two devices at most. Not even sure if this concept would work but I figured I would ask here.