How do I decide which ARM board to go for if I am aiming to use it as a micro-controller to run sensors, actuators, motors, and solar panels? And I wish to power up the board via Li-ion battery pack.
Choosing a good arm card is quite complex because there are many. Everything will depend on the project you want to realize. The number of associated peripherals, uses (WiFi, ethernet, HDMI, ...). The environment is also important (embedded or not use, the electric power available: battery, power, solar panel, ...). We can help you in your choice but you should be a little more explicit when at the final use you want to do.
For make the good choice you have to tell us, expressly the numbers of captor, actuators, motors, the electric consummation you mean acceptable and the approximate size of software you mean use on it.