Battery pack charging apparatus and method

DETAILED DESCRIPTION What is claimed is: 1.
A charging apparatus for charging a plurality of detachable battery packs, said charging apparatus comprising: a charging device configured to charge the plurality of battery packs one after another; a monitoring device configured to monitor attachment of a battery pack to the charging apparatus; a memory configured to store attachment history data based on monitoring of the battery pack by the monitoring device; a switching device operative to switch from one of the battery packs to a next one of the battery packs; a voltage detecting device configured to detect a voltage of the next battery pack before charging of the next battery pack commences; a charging manner setting device operative to set any one of constant current charging and constant voltage charging in accordance with the voltage detected by the voltage detecting device; and a charge current detecting device configured to detect a current during charging of the next battery pack.
2.
The charging apparatus according to claim 1, wherein when the detected voltage is lower than a first voltage level a preparatory charging process is performed to the next battery pack until the detected voltage increases to the first voltage level, when the detected voltage is higher than the first voltage level a constant current charging process is performed until the detected voltage increases to a second voltage level, and after the voltage of the battery pack has reached the second voltage level a constant voltage charging process is performed until charge current flowing through the battery pack becomes less than a prescribed level.
3.
The charging apparatus according to claim 1, wherein when the switching device switches to another battery pack, and said another battery pack is recognized as new based on attachment history data of said another battery pack from the memory, charging of said another battery pack is performed by starting from a determination process for determining whether the detected voltage of said another battery pack is higher or lower than a first voltage level