Patent ID: 8680814

Claim:
A battery charger for charging a parallel-arrangement battery pack comprising a plurality of secondary batteries arranged in parallel, comprising: a charge parameter change means for setting and changing a charge parameter, a charge current detection means for detecting charge current, and a battery SOC detection means for detecting individual SOCs of the secondary batteries, wherein the battery charger starts charging with the charge parameter set to a first value by the charge parameter change means, the first value being predetermined to ensure that the secondary batteries are charged up to and maintained at a predetermined SOC lower than full charge, and when the charge current detection means detects that the charge current has decreased to a predetermined value, goes on charging with the charge parameter set to a second value by the charge parameter change means, the second value being predetermined to enable the secondary batteries to be charged up to full charge, and when the battery SOC detection means detects that at least one of the secondary batteries has reached full charge, terminates charging.