Energy storage using electrochemical battery systems has been widely addressed as a key element to enable widespread integration of renewable energy. Here, an updated battery model is investigated in order to allow accurate standalone photovoltaic (PV) systems simulation, for performance assessment and long-term energy prediction. Battery models have been largely described in the literature. However, this study reviews the most commonly used models in PV application such as Shepherd, Manegon, and Coppetti models in order to validate the suitable mathematical model. The updated battery model based on experimental results and parameter extraction procedure is carried out using sealed gelled lead/acid battery during charge and discharge processes. A comparative analysis based on statistical tests and optimisation method confirms the effectiveness of the most accurate model among the three models using new proposed parameters. The simulation results of the model with new coefficients are compared with measured data, recorded from battery charge and discharge test bench to validate the accuracy of the updated model.