| 摘要 |
To prevent a battery from being over-discharged and to thus improve a cycle life of the battery, a microcomputer electrically interrupts connection between the battery and a cordless power tool to compulsorily stop driving the tool when the battery voltage has become equal to or fallen below a first predetermined value. Also, to enable an operator to know that the battery is in a near over-discharge condition, the microcomputer performs a switching control of a load current when the battery voltage is above the first predetermined voltage but has become equal to or falls below the second predetermined voltage. As a result, the rotation of the motor of the tool goes abruptly slow down or the motor rotates in an irregular fashion, whereby the operator recognizes that the battery is in a charge-need condition.
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