Refresh charging method for an assembled battery constituted from a plurality of lead-acid storage batteries and charging apparatus

摘要

Provided are a refresh charging method and a refresh charging apparatus for an assembled battery constituted from lead-acid storage batteries, by which a necessary charging rate may be performed while shortening a charging period. In a constant voltage charging mode, n intermediate threshold values S₁ to S_n which decrease stepwisely are set between a predetermined threshold value S₀ and a lower-limit current value, and n additional timer periods T₁ to T_n are set where n is an integer equal to or larger than one. Counting of the n additional timer periods T₁ to T_n is respectively started when the charging current reaches the n intermediate threshold values S₁ to S_n. A maximum timer period T_m and the n additional timer periods T₁ to T_n are set to satisfy a relationship of T_mT₁ . . . T_n. Charging is stopped when the counting of one of the maximum timer period T_m and the n additional timer periods T₁ to T_n is completed before the lower-limit current value is detected.