Two sets of phase change material (PCM) cooling systems experiment have been set up and investigated to enhance the efficiency of thermal dispersion for a small photovoltaic system. The experimental investigations have been done to obtain the high frequency data including temperatures, electrical power output of the photovoltaic panels, and environmental nature parameters such as solar radiation. To obtain the enhancement of efficiency due to the PCM cooling system, two contrast sets of identical size PV systems have been measured transiently at the same time. This natural convection based cooling system with phase changed material can help maintaining a relative more stable low temperature range for the immersed PV panel. The present experimental result shows that the present PCM cooling system can decrease the collector averaged temperature 1.49°C less than the pure water cooling system during the high solar radiation period and the improvement of corresponding PV output power is 6.71%. Finally, present experimental results show that using PCM is an effective way to maintaining lower PV working temperature and high level electrical transition efficiency.