[12V & 24V Car Battery Tester]: AUTDER AD-808 car battery tester works with all 12 volt and 24 volt batteries for vehicles, cars, motorcycles, trucks, mobile homes, all vehicles -terrain, SUVs, boats, yachts and mowers, even golf carts. The accuracy of car battery voltmeter is close to 0.01V, e.g. B. 12.29 V. [Generator Charging System Analyzer]: In addition to providing a quick read to see if a vehicle battery needs a crack or replacement, it can also test the output status of the generator to prevent damage to the battery due to overcharging or incomplete charging. [Ease of use]: We have creatively developed three speeds to test the alternator, 12V battery and 24V battery. If you keep the driveway in the middle, the LCD screen will show the voltage in real time, the LEDs will show the status of the generator. When switching to 12V or 24V, the LCD screen displays the real-time voltage and the LEDs indicate the battery status. [Reverse connection and overvoltage protection]: During connection reversed, the error code "ERR" will be displayed on the LCD screen and the built-in buzzer will sound. The test range for digital voltage is 4 to 20 V DC. If the voltage is out of range, LO ( 4V) or HI ( 30V) will appear on the screen.