the goal of this paper is to use the solar power to charge Lithium-ion (Li-ion) batteries, pulse width modulator (PWM) control method is implemented to design and build a solar battery charger prototype.Maximum power point tracking (MPPT) is used in the photovoltaic (PV) system to maximise the PV output power, irrespective of the temperature and irradiation conditions.MPPT system, consisting of a buck-type dc-dc converter, which is controlled by a microcontroller unit, is implemented.It is presented a model for the lithiumion battery (Li-Ion) that is suitable for computer simulation.The used model can be easily modified to fit data from different batteries.The simulation results achieved by using Pspice programs and are in good agreement with the experimental results.These results allowed demonstrating the reliability and validity of the proposed MPPT technique.The battery charger prototype was tested and the results obtained allowed to conclude about the conditions of permanent control on the battery charger.