| 摘要 |
PROBLEM TO BE SOLVED: To provide a vacuum cleaner which prevents a lowering of charging cycle life of a battery by controlling charging current. SOLUTION: A state of charging is sensed by detecting a voltage of a charge sensing part 42, and charged by energizing a transistor Q1 for 1 ms of conducting period t. A resistance R1 of an input voltage detecting pare 44, a power source input voltage V1 between serial circuits of a storage battery E, and a battery voltage V3 between both electrodes of the storage battery of a battery voltage detection part 45 are detected. In case that the battery voltage V2 is smaller than a prescribed voltage Vy, and residual charge of the storage battery E is small, by calculating (V1-V2)/t and setting a mean value of charging current as I, 0.1 ms is added to the conducting period t so as to become a prescribed current I0. When the conducting period t of the transistor Q1 exceeds 7 ms as 70%, it is reset to 7 ms. A charging current with big current value is prevented. The mean current value I for charging becomes constant, and the life of the storage battery E is improved. Also a storage battery with different rated current value can be charged.
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