In this paper, a new power electronics topology and battery charging method is introduced. The topology is based on a bidirectional isolated Cuk converter. The charging method provides positive and negative current and resting periods. This charging method results in less generated heat and longer battery life cycle. During charging cycle, constant current is applied to the battery from the source. In discharging cycle, which is a small fraction of full period, the battery is discharged with constant current and the energy storage capacitor is charged. In resting period, no current is applied to help with the electromechanical reaction and neutralization of the battery's internal electrolyte. Different operating modes of the system and its small signal analysis are presented in this paper. Simulation and test results are also provided to validate the mathematical analysis.