Stand-alone solar system is solar system that is not connected to the grid. The stand-alone system requires battery as energy storage to store energy that is collected by the solar panel and to supply power consistently. The objective of this research is to revise an existing stand-alone system beside BH building in Universiti Tenaga Nasional. Every equipment in the existing system shall be checked using proper equipment to determine the functionality of each equipment. Simulation of the solar panel is done using MATLAB SIMULINK to compare the results obtain from the existing solar panel. PSCAD software was used to simulate Surge Protective Device (SPD) and to determine whether the application of SPD can protect the entire system or not.