ELI5: Explain Like I'm 5

Battery charger

A battery charger is a device that helps make sure your battery has enough energy so it can work properly. It works by taking energy from a wall outlet or solar panel and turning it into a form the battery can use. It then connects to the battery and sends energy into it to charge the battery's cells. When complete, the charger will lets you know that the battery should be ready to use.