This paper presents the design and simulation of a three-stage solar battery charge controller using ?uk DC-DC converter, functioning as the major interface between the solar PV module array and the battery bank. The charging current and voltage curves for the three – stage charge controller were obtained and discussed. The simulation curves for the converter in open – loop and closed – loop modes with and without PID controller, respectively, were also compared and discussed. The commonly used converters in solar charge controllers normally step down the non-linear DC voltage supplied by the PV module array to a stabilized desired DC voltage value, required to charge the battery bank. The ?uk DC-DC converter used in this paper has the capability of stepping down as well as stepping up the supplied DC voltage among other advantages, which include, minimum ripples at the output stage, faster rise and settling time and getting closer to the desired output value.