programming for switching between batteries and supercapacitors

Hi there. I'm currently doing a project to switch between the two energy sources. The vehicle will use the supercapacitors as the starter and later it will switch to battery with a specific time. Anyone can help me with the programming? Btw, I use Arduino Uno.

You can use SPDT solid state relay then once the car starts, you start a timer to then switch the source. You may/will also need a capacitor to provide a smooth transition.