The charge controller is the heart of any solar powered system like this. It takes the power from the solar panel and charges the battery in a precisely controlled way. Not too much if it's full and plenty if it's low in charge. Batteries can be expensive so it's worth having something that looks after them!

The diagram also shows an inverter attached to the battery. The inverter converts the battery voltage into mains voltage so you can run things like computers, lighting or other mains voltage appliances from the power stored in the battery.

Some charge controllers have a low voltage DC output where you can connect 12 or 24 volt lighting. This output is controlled by the controller so if it senses that the battery is running low it automatically turns this output off and protects the battery from being damaged by deep discharge. 

Learn more about how to choose the right components for your solar power or solar lighting kit here