Patent ID: 7759822
Filing Date: 2010-07-20
Classification: H02J

Abstract:
1. An uninterruptible power supply device for supplying power to a load and for floatingly charging a storage battery from a converter connecting to a alternating current power source, and having a degradation judgment circuit for the storage battery, the degradation judgment circuit comprising; a control circuit for controlling an output voltage of the converter to be lower than a steady state, so as to cause the storage battery to discharge at a more limited current than the rated current of the storage battery, and so as to cause the converter to supply a part of load current to the load; a judgment circuit that judges the degradation of the storage battery based on a charging time when the control circuit controls the output voltage of the converter to return to the steady state voltage to a time when the battery is fully charged, the judgment circuit including a timer connecting to a comparator for comparing a charging current of the storage battery with a base current, which use the charging time to determine whether the storage battery is degraded or normal, a degraded storage battery having a maximum storage capacity that is less than a maximum storage capacity of a new storage battery of the same kind thereof.