A battery control system for controlling charging/discharging of a nickel-metal hydride battery having a hysteresis characteristic for a relationship between voltage and a state of charge, the battery control system comprising: a storage medium configured to store information regarding a plurality of state of charge use ranges having different state of charge upper and lower limits; and a control circuit configured to select one of the plurality of state of charge use ranges depending on a condition of use according to a temperature of the nickel-metal hydride battery to control the charging/discharging of the nickel-metal hydride battery in accordance with the selected state of charge use range, wherein: the plurality of state of charge use ranges include a first use range , and a second use range that includes an state of charge of the same level as the state of charge lower limit of the first use range , characterized in that the control circuit is configured: to detect a voltage of the nickel-metal hydride battery and calculate the state of charge therefrom; to determine whether a current state of charge of the nickel-metal hydride battery is equal to a predetermined state of charge that is included in both the first use range and the second use range ; when it is determined that the current state of charge is equal to the predetermined state of charge, to obtain information regarding a memory effect of the nickel-metal hydride battery ; and to control the discharging of the nickel-metal hydride battery by lowering a lower limit voltage of each of the state of charge use ranges using the obtained information regarding the memory effect. a storage medium configured to store information regarding a plurality of state of charge use ranges having different state of charge upper and lower limits; and a control circuit configured to select one of the plurality of state of charge use ranges depending on a condition of use according to a temperature of the nickel-metal hydride battery to control the charging/discharging of the nickel-metal hydride battery in accordance with the selected state of charge use range, wherein: the plurality of state of charge use ranges include a first use range , and a second use range that includes an state of charge of the same level as the state of charge lower limit of the first use range , characterized in that the control circuit is configured: to detect a voltage of the nickel-metal hydride battery and calculate the state of charge therefrom; to determine whether a current state of charge of the nickel-metal hydride battery is equal to a predetermined state of charge that is included in both the first use range and the second use range ; when it is determined that the current state of charge is equal to the predetermined state of charge, to obtain information regarding a memory effect of the nickel-metal hydride battery ; and to control the discharging of the nickel-metal hydride battery by lowering a lower limit voltage of each of the state of charge use ranges using the obtained information regarding the memory effect. to detect a voltage of the nickel-metal hydride battery and calculate the state of charge therefrom; to determine whether a current state of charge of the nickel-metal hydride battery is equal to a predetermined state of charge that is included in both the first use range and the second use range ; when it is determined that the current state of charge is equal to the predetermined state of charge, to obtain information regarding a memory effect of the nickel-metal hydride battery ; and to control the discharging of the nickel-metal hydride battery by lowering a lower limit voltage of each of the state of charge use ranges using the obtained information regarding the memory effect. <EOS>