... -performance Li-battery, continuous work 8 hours without any external power, convenient for filed test.3.Multiparameter, can test voltage, ... current fundamental wave,264 times harmonic wave, phase position, frequency, power, power factor and so on.4.Can set up different storage ... 0.01HzVoltage deviation≤0.2%Phase angle error≤0.1%Power deviation≤0.5%Display screen320×240,Colorful LED screenCharge ...