Someday I want to have a solar powered home, and I've been gathering supplies for it. I have about 710 Amp Hours worth of batteries, but I keep shying away from buying the panels, which tend to run in the hundreds of dollars. Obviously, this dream will have to wait.
Or will it? An electronics engineer has created a system to automatically switch between a solar-battery system and mains power. Why? The solar-battery system is free to you once paid for, but it can run down, especially if there's multiple cloudy days in a row or if your need for electricity is high (especially for air conditioning in hot summer months...my home city is technically a swamp.)
The system periodically takes a read of the battery capacity. If it's full it swaps the entire house over to battery power. If it's half full, it starts swapping circuits back to mains. And if it's empty...mains for you while the system recharges. Once set up, the user of this system could get the most economical power possible at all times.
One issue -- there is a brief cutoff while it swaps electrical systems. Users of lamps and refrigerators probably won't notice. Users of computers would have theirs inexplicably reboot. A UPS (uninterruptable power supply) would be required for all computers in this house. Preferably with the alarms turned off, as they by default sound an annoying alarm every time there's any issues with the power whatsoever.