Ensuring that the electrical current only flows in one direction “OUT from the solar panel” of the series array to the external load, controller, or batteries.

Blocking diodes are basically used in solar photovoltaic arrays when there are two or more parallel branches, or there is a possibility that some of the array will become partially shaded during the day as the sun moves across the sky. The size and type of blocking diode used depend upon the type of solar photovoltaic array.

This is widely used when you have multiple solar arrays connected under different angles or locations.