Comprehensive Investigation of Performance Degradation of Old Photovoltaic Panels at Outdoor Exposed Condition: A Case Study in Bangladesh

This study investigates the comprehensive investigation of performance degradation of 10-watt old photovoltaic (PV) panels after four years in outdoor exposed conditions in Bangladesh. In this research, the photovoltaic panels were investigated for both visual identification of faults and electrical characteristics of the open circuit voltage, short circuit current, and maximum power. Observations from both sides indicated many different kinds of degradation causes, such as permanent dust, back-sheet damage, minor hotspots, and minor discoloration. Additionally, a PV analyzer was used outside of the module to evaluate electrical operation, and experimental findings showed how the panels degraded with time. The maximum output power of the old panel was found 9.911 watts and the minimum output power was 9.449 watts, The maximum and minimum percentage degradation rates for four years were 5.51 % and 0.89% respectively, and the maximum annual degradation rate of each panel was 1.3775 % among ten panels, and average annual degradation rate 0.6925% with the comparison between the measured data and the rated specifications. This study was conducted between both visual fault identification and observed change in the electrical output of PV panels for four years.