UNINTERRUPTIBLE POWER SUPPLY UNIT

摘要

In an uninterruptible power supply unit (10) of the present invention, during the charging of a first battery pack (121) and during the time interval until the voltage (V21) of the first battery pack (121) drops down to the upper limit voltage or less of a load device (30) after the first battery pack (121) is charged up to a fully charged state, the first battery pack (121) is not allowed to discharge and a second battery pack (122) is allowed to discharge. During the charging of the second battery pack (122) and during the time interval until the voltage (V22) of the second battery pack (122) drops down to the upper limit voltage or less of the load device (30) after the second battery pack (122) is charged up to a fully charged state, the second battery pack (122) is not allowed to discharge and the first battery pack (121) is allowed to discharge.