Abstract
In this paper is presented a numerical method for measurement and analysis of the charging characteristics I-λ-t (battery current-irradiance-time) of storage batteries for photovoltaic (PV) power systems. The experimental data is obtained from the PV modules by a data acquisition system built in the charger component. An algorithm developed as a Matlab source code is used to model the charging characteristics of the batteries connected to a PV system. Using the interpolation method, the mathematical function of total battery current and depending on time and illumination are obtained. The numerical values of the errors between the theoretical and experimental results prove the accuracy of the proposed method.