I want to run a number of mains powered appliances from a 12V battery. The battery is charged from solar panels, and I have a pure sine inverter running from the battery.
Now I want to switch automatically between mains power from the grid and mains power from the inverter. That is: take power from the inverter when battery can deliver, otherwise from the grid. So I need a switch. Requirements are:
Must break before connect, but connect so fast that appliances will not discover.
I am considering a good old mechanical relay or back-to-back power mosfets optically controlled.
Other ideas are welcome. I already have an AVR, controlling loads from the battery depending on state of charge, it can easily control inverter and switch too.