Electronic apparatus with low power consumption, and control method and storage medium therefor

A control method for an electronic apparatus constituted by plural apparatuses that operate when supplied with power and including a conversion unit configured to convert AC power supplied from an AC power source into DC power for output and a secondary battery configured to be charged with the DC power output from the conversion unit and configured to be capable of supplying power to a part of the plural apparatuses, comprising:

• a switching step of being capable of switchingly supplying to the part of the plural apparatuses, on a per apparatus basis, either the DC power output from the conversion unit or power from the secondary battery;
• and
• a control step, in a case where conversion efficiency of the conversion unit attained when required power for all apparatuses to be operated, among the part of the plural apparatuses, is supplied from the conversion unit is higher than power use efficiency attained when the required power is supplied from the secondary battery, of controlling said switching step such that the DC power output from the conversion unit is supplied to the apparatuses to be operated, and in a case where the power use efficiency is higher than the conversion efficiency, of controlling said switching step such that power is supplied from the secondary battery to the apparatuses to be operated.