Change solar power supply to AC charging
240KW/400KW industrial rooftop - commercial rooftop - home rooftop, solar power generation system.
My idea: Get a large capacity 12V battery, a smart/trickle charger, 12VDC relay, and a large AC/DC 12V power supply. Relay coil connects to the power supply. Relay contacts switch the load between (NO) the power supply output and (NC) the battery. Add a buck converter for 5V devices. Add low battery protection as you described above.