| 摘要 |
PROBLEM TO BE SOLVED: To detect the amount of power remaining in a battery with higher accuracy than before.SOLUTION: A remaining power detection unit 14 includes: a voltage detection circuit 14a for detecting a voltage value of a battery 6; a current detection circuit 14b for detecting a current value of the battery 6; and a CPU 14c. The CPU 14c determines the remaining power of the battery 6 by a voltage method on the basis of the voltage value detected by the voltage detection circuit 14a, and determines the remaining power of the battery 6 by a current integration method on the basis of an integration value of a current value detected by the current detection circuit 14b. The CPU 14c acquires a first value corresponding to gradient of changes within a prescribed time in voltage value detected by the voltage detection circuit 14a. The CPU 14c selects the voltage method when the first value is smaller than a threshold, and selects the current integration method when the fist value is larger than the threshold. |
