It is a compact unit for regular maintenance of single cell, especially for old cell. It plays three roles for complete solutions: charger, discharger and activator, which will facilitate your maintenance for batteries. The three functions could be used individually or comprehensively. When used comprehensively, lag-out battery will experience low-volt constant current charging and discharging in one or multi-circles (1~99). By activating the disabled Active-Material on battery electrode plate, it amends the battery malfunction caused by chemical failure and thus boosts the capacity of battery. it is very significant for resources utilization and efficiency increasing.