DefinePK

Abstract

The effect of battery characteristics on the performance of PV Energy System is experimentally investigated. The employed system consists of a number of lead acid storage batteries, a set of photovoltaic (PV) panels, a charge controller, DC/AC inverter and an electrical load. The system also employs a monitoring unit (MU) that consists of voltage and current sensors and data acquisition cards. The MU was specially developed to monitor energy system performance parameters; such as PV voltage and current, battery voltage, battery charging and discharging currents and inverter current. The monitoring unit is controlled through a specially developed, LABVIEW® based, computer program. In the study, the effect of battery SOC on charging and charging efficiency was investigated. Also, the effect of battery’s loading conditions on its useful charge was investigated. Finally, the effect of battery SOC and supported load on battery performance was investigated. Results of the study showed battery’s SOC had a minimal effect on charging efficiency. It also showed that higher discharge current (load requirements) leads to significant decrease in energy system performance caused by decrease of battery discharge efficiency by up to 50%. On the other hand, low batteries SOC proved to have insignificant effect on meeting load demand. The results emphasize the importance of proper selection of batteries size as well as characteristics including cost, to match load requirements, as those would highly affect renewable energy system’s performance and feasibility.