I need to create a interruption-proof power for a project of mine, very similar to the design of this link.
My problem is that I need to adjust the current delivered of the solar panel (21V, 1.2A) to 5V and simultaneously charge a battery 12V, 18Ah. If the solar panel does not supply power, the battery takes its place.
Does anyone know any circuit to do something? Or can someone give me a light as do something?