Abstract: An electrical power system is provided for supplying DC power to electrically motorized vehicles, emergency standby sources, and the like wherein a lead-oxygen battery cell used as a source of DC power includes a positive charging grid, a conventional negative electrode, a positive discharging electrode, and a teflon membrane member coated with a catalyst contained in an atmosphere of oxygen which is admitted to the cell through the teflon membrane. Oxygen is given off during the charging cycle and is compressed in a storage tank for re-use during each duty cycle providing a closed system wherein contamination is minimized and a long-life cycle can result.