Abstract
This paper studies the case of electric vehicles (EV) with D.C. motors, where the power transfer is obtained by D.C. choppers, the charging degree of the battery has a big importance in the performances of EV.
A new battery has a small internal resistance, and this increase with the aging of the battery. Also a bad maintenance and a wrong charging of the battery grow up this internal resistance having direct consequences upon the autonomy of EV. The author present the study of the influence of the internal resistance of a battery in the case of power transfer through buck converter, this one being the most useful converter for the EV with D.C. motors. The calculus and graphics regarding the influence of internal resistance of a battery, in case of power transfer through buck converter versus frequencies and duty factor are presented.