Secondary battery device

A secondary battery device is provided, comprising: a secondary battery capable of being charged and discharged; a charger for charging the secondary battery, the charger operating in at least two operation modes including first and second operation modes in which said secondary battery is charged to predetermined charge end voltages different from each other, and the charge end voltage in said first operation mode being set higher than the charge end voltage in said second operation mode; a time measuring device; and a timer device for switching the operation modes of said charger based on a time acquired from the time measuring device and a schedule previously stored.