Abstract: A backup power supply device to be connected to a conduction path from an external power supply to an external load includes a plurality of secondary batteries connected in parallel, a plurality of charging switches that can individually pass and cut off charging power from the conduction path to the plurality of secondary batteries, and a control device for performing discharging control on the plurality of secondary batteries when the power supply voltage of the conduction path drops below a predetermined power failure detection threshold value. When battery voltages of the plurality of secondary batteries drop below a predetermined charging start threshold value, the control device performs charging control with a time difference set between charging start timings of the secondary batteries.

Abstract: A power storage control apparatus includes a processor that computes a remaining charge time of a power storage apparatus that supplies power to a load apparatus operating by power supply from an external power source in case of a power supply emergency of the external power source, and the processor computes the remaining charge time of the power storage apparatus based on linear approximation of correlation between an operating environment of the power storage apparatus and a charge time of the power storage apparatus including a charge stop time.

Abstract: A battery indicator estimates a remaining battery capacity when a controller instructs a driving power source to start the power supply based on a battery voltage detected at a timing when the controller instructs the driving power source to start the power supply. The controller instructs the driving power source to stop the power supply after the discharge of a secondary battery by a charge-discharge circuit is ended and at a timing when a battery voltage being measured by a voltage measurer is stabilized.