Patent ID: 7944175

Claim:
A system for charging a power tool battery, comprising: a battery side connector and a charger side connector electrically connected to each other; a charging device that charges the battery when the battery side connector and the charger side connector are electrically connected, the charging device comprising: a memory device that stores data of a plurality of sound patterns; a selecting device that selects a sound pattern data from the data of the plurality of sound patterns stored in the memory device; and a sound generating device that generates a sound based on the selected sound pattern data when the charging operation of the battery by the charging device is completed, wherein the sound pattern data includes at least a first sound pattern data and a second sound pattern data, the selecting device selects the first sound pattern data when the battery side connector and the charger side connector are connected to each other, and the selecting device changes the first sound pattern data to the second sound pattern data when the battery side connector and the charger side connector are disconnected and reconnected to each other after selection of the first sound pattern data, regardless of a charging state of the battery.