This is smart solar charge controller. You can connect solar panel. Battery. Load all together in the controller. Controllerhas the features to protect the battery from over change and low discharge. Controller has also facility to change phones. There are two USB plug of max 2.5 A currentrating for direct phone charging. Current Support - max 10A Means you can connect maximum load current or charging current of 10Amps. Simply 50 watts panel privide 1.5 A current. So you can able to connect aprox 600 watts panel to this controller.