The internal resistance of the battery is the key factor affecting the charge-discharge balance of the battery in series. The battery tester can help to judge the deterioration state of the battery. When selecting the type of battery tester, the functional indexes such as maximum voltage, maximum resistance, test accuracy and whether it supports testing in circuit or not should be taken into account. UNI-T Battery Tester has the characteristics of high precision, high resolution and ultra-high speed measurement. Compact and beautiful design, rich communication interfaces, can efficiently complete remote control and data acquisition functions can be used for almost all battery internal resistance testing, including lithium battery, lead-acid battery, button battery and other battery pipeline inspection.