| 摘要 |
PROBLEM TO BE SOLVED: To provide a power supply unit efficiently operating monitoring means for monitoring the voltage of a secondary battery to reduce power consumption.SOLUTION: The power-supply unit used for a power tool comprises: a battery set formed by connecting a plurality of secondary battery cells; a connection part connected to at least one of the power tool and battery connection means of a charging device; monitoring means monitoring the voltage of at least one of the plurality of secondary battery cells, and outputting a signal to the outside when a voltage value or a current value of the battery set is within a predetermined numerical range, or when out of the numerical range; and breaking means breaking current output from a port from which the monitoring means outputs the signal. The monitoring means includes: a monitor mode in which the monitoring means monitors at least the voltage of one of the plurality of secondary battery cells; and a standby mode in which the monitoring means breaks an internal circuit for monitoring the voltages of the plurality of secondary battery cells. The breaking means breaks the output of the port when the monitoring means is in the standby mode. |
