Inverters installed in the photovoltaic (PV) powered uninterruptible power supply (UPS) system consist of battery and also PV module. An optimum number of PV module and battery should be considered to reduce costs and technical works. The PV powered UPS system is operated directly by the PV module, therefore, an optimization sizing of PV powered UPS system should be studied in terms of optimum PV module number that related to the power capacity of PV powered UPS system, solar radiation and temperature. This paper presents an optimum sizing of PV powered UPS system application. A mathematical modeling is created to obtain the optimum number of PV module and battery. The result shows that for 12V, 100W PV powered UPS system applying the 60W, 21V PV module, 12V, 100Ah battery, 700W AC load power, thus, the optimum number of PV module and battery are 20 modules and 5 pieces, respectively.
