VEHICLE POWER SUPPLY

PROBLEM TO BE SOLVED: To provide a vehicle power supply easily and highly accurately detecting the cell short abnormality of a capacitor. SOLUTION: The vehicle power supply is equipped with: the capacitor 1 constituted of a plurality of directly connected capacitor cells connected in series; a motor generator 2 supplying power to the capacitor 1 through the regenerative braking at the deceleration of a vehicle; a capacitor voltage current detecting means 3 detecting the voltage and current of the capacitor 1; and an abnormality determining means 7 determining the presence/absence of the cell short abnormality of the capacitor 1 based on the voltage and current of the capacitor when the motor generator 2 supplies power to the capacitor 1. When the increase rate of the capacitor voltage to the integrated value of the charging current flowing into the capacitor 1 is a predetermined threshold or lower, the abnormality determining means 7 determines that any one or more capacitor cells constituting the capacitor 1 have a cell short abnormality. COPYRIGHT: (C)2010,JPO&INPIT