The way PV are used is generally divided in to the following catagories
Simple PV Systems
Simple systems are used for devices which do not need to be operating
all the time. Eg. A water pump.
Battery PV Systems
A battery system's are generally used for unatennded devices which need
to be running all the time or during the night. Eg. a park light.
Generator PV Systems
Generator systems are used when the PV's cannot provide all the electricity
required to run the Device. Eg an airconditioner.