What would be the best method of switching between a solar cell and a battery, I'm currently implementing a system that is functional so long as the solar cell outputs a voltage between around 2V to 7V (7V is the max voltage the panel can output). However, once the panel output dips below 2V the system won't be able to function correctly.
What would be the best way of implementing a battery backup system of some sort so that once the panel output drops below 2V the battery will take over and provide a steady 5V for example, and once the panel goes back to producing above 2V the system switches back to being solar powered.
Since posting, I have been looking into Relays - what would be the advantages and disadvantages of using a Relay Module controlled by an arduino? A relay module such as the 'Parallax 27115' looks like it'd do the trick. That way I could electronically control when to switch between power sources using the arduino? Is this a good solution?