Abstract: The valve control type lead-acid sealing battery has strict request to charging current, the voltage, the time and the temperature. The characters of maintenance-free accumulator were introduced, such as maintenance, seal, temperature and charge. The disadvantage of direct current operation way in the Hua’an hydropower station was pointed, and the improvement method on the replacement and charge way technique was suggested, while the complete set microcomputer charging set transformation was transformed. The system was stable after the improvement.

Key words: maintenance-free accumulator, constant-voltage &, current-limiting, microcomputer control, GZDW DC power set