Using the most advanced AC discharge test method, it can accurately test the voltage and internal resistance at both ends of the battery, and judge the battery capacity and technical status of the battery. Customers can choose according to their own situation according to the internal resistance test, voltage test, and capacity estimation of batteries used in the communication industry. As the basis for the matching of the internal resistance of the new battery; the internal resistance of the battery is tested before and after discharge to identify the real backward battery; the key operation and the liquid crystal touch are two operating modes; it can test the battery in Strings or single cell.