The VAG series volt-ampere meter is a new type of coulomb counter that can measure various physical parameters such as voltage, current, power, charge and discharge capacity, watt-hours, time, etc. It can also set parameters to realize multiple protection functions such as over voltage protection, under voltage protection, over current protection, overpower protection, over temperature protection and time limit protection.The meter can automatically identify the direction of the current, and can monitor the battery capacity in real time and display the measured data in use color LCD screen. The VAG series voltage and current meters add voltage and current curve display and export functions on the basis of the original functions. At the same time, the mobile phone APP and host computer can be used to control, and the firmware can also be updated and upgraded in real time.