The short summary and promotional piece accompanying a creative work is about for battery charger system using ZCS (PWM) Resonant Converter Dc-Dc Buck. The aim and scope of this work to investigate the high efficiency of charging for battery level. The idea is forced to gain high efficiency, low circuit volume, minimize switching losses and satisfactory performance. The brief discussion of battery charger system and on use able functional methods. The short study of circuit descriptions, operating modes, output voltage gain and normalized voltage gain is also summarized. This high repetitious work which will give gratification fulfillment with the theoretical predictions to readers. I have special thanks to Engr. Rizwan Jamil to help me with research and development of the scope of this work.