Two-way detection of current, users who detect charge and discharge can automatically identify and detect two-way current without changing the wiring direction. Power-off memory function, after power-off, the AH number before power-off can be memorized, which is convenient for observation and measurement. The time and AH number reset function does not affect measurement. The AH number can be filled up without affecting direct discharge measurement. It has protection functions such as overvoltage, overcurrent, overpower, time limit and overcharge. Voltage, current, charging capacity AH number, WH number, time, power are displayed at the same time, the display information is comprehensive and clear. The current is detected by the Hall sensor, and the wire that the current passes through can be passed through the round hole of the sensor. The current can be detected in both positive and negative directions, safe and convenient. This volt-ampere meter is a new type of volt-ampere meter that can measure physical quantities such as voltage, current, charge and discharge capacity, time, power, etc.The instrument uses color LCD to display the measured data, and the display information is comprehensive and user-friendly. This meter uses a Hall sensor to detect current, which is convenient and simple, and is very suitable for applications that need to monitor the output voltage and current, and charge and discharge the battery. Current measurement range: 0-500A Display resolution: 0.2A Voltage measurement range: self power supply (12-90) V external power supply (0-90) V Current accuracy: +/- 3% +/- 5 words Voltage accuracy: +/- 2% +/- 5 words Voltage: 0.01V Capacity: 0.01AH Time: 0.01H (1min) Measurement rate: 5 times/sec OVP (over voltage protection): 0.01V-90V OPP (over power protection): 0.01W-9.99KW (undervoltage protection): 0.01V-90V OCP (Over Current Protection): 0.1-100A (overcharge protection): 0.01AH-9999AH OFT (overtime protection): 1min-99hour59min colour: black Material: plastic size: 7.9x4.3x5.2cm Package Contents: 1 x Voltage and current meter Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.