Power supply system and state of charge estimating method

This application is based upon a Japanese patent application, serial number 2000-093726, entitled "Power system For Running Vehicle", of Ookoshi et al., filed on Mar. 30, 2000, Japanese patent applications, serial numbers 2000-128741, 2000-128742 and 2000-128743 entitled "Power system For Running Vehicle", of Shimoura, Ookoshi et al., filed on Apr. 28, 2000, a Japanese patent application, serial number 2000-209284, entitled "Power system For Running Vehicle", of Okuda et al., filed on Jul. 11, 2000, a Japanese patent application, serial number 2000-228688, entitled "Power system For Running Vehicle and State of Charge Estimating Method for the System", of Ookoshi et al., filed on Jul. 28, 2000, a Japanese patent application, serial number 2000-231620, entitled "Power system For Running Vehicle", of Okuda et al., filed on Jul. 31, 2000, and a Japanese patent application, serial number 2000-231621, entitled "Secondary battery For Running Vehicle", of Maeda et al., filed on Jul. 31, 2000. A power system where energy generated at a deceleration time of a running vehicle such as an automobile can be accepted as regenerative energy sufficiently and safely is provided. In a power system a non-aqueous solution system secondary battery group where 10 to 11 lithium ion secondary battery cells are connected in series and an aqueous solution system secondary battery group where control valve type lead-acid battery cells are connected in series are connected in parallel. The battery capacity of the non-aqueous solution system secondary battery group is smaller than that of the aqueous solution system secondary battery group The non-aqueous solution system secondary battery group and the aqueous solution system secondary battery group are charged at a current value of C or less from a motor generator and the ratio of the charged current value of the aqueous solution system secondary battery group to the charged current value of the non-aqueous solution system secondary battery group is 0.05 to 1.00.