Charging Mode IN: By setting the upper voltage limit UP and lower voltage limit dn; when the battery voltage lower voltage limit dn, the relay conducts, and the charger starts charging the battery; when the battery voltage upper voltage limit UP, the relay de-energizes, completing one automatic charge cycle; when the relay is on, IN flashes, indicating charging is in progress.Note: This product is a simple voltage controller, using a relay to turn the output on and off. It only functions as a switch and does not transform voltage.Function Description:1. Voltage percentage calculation: Battery voltage / (Upper voltage limit - Lower voltage limit)2. Button functions:UP button: Short press toggles between displaying percentage and time; long press for 5 seconds to switch modes: Charging mode: IN, Discharging mode: OUT.SET button: Short press to view currently set parameters; long press the SET button to enter the parameter setting interface, setting UP: upper voltage limit, dn: lower voltage limit, OP: conduction time, dOP: delay conduction time (0-999 seconds), and FOP: forced conduction time (0-10 seconds) in discharge mode.DOWN button: Short press to turn the relay enable (emergency stop function) off. After turning off, the LCD displays OFF, and the relay is disconnected.Long press the DOWN button to set the LCD backlight status: L-P: OFF (backlight always on), ON: backlight automatically turns off after 5-10 minutes; wake up by pressing any button after turning off.3. Parameter Settingsa. Enter the parameter settings interface by long-pressing the SET button;b. After entering the parameter settings interface, switch parameters by short-pressing the SET button;c. After selecting a parameter, you can set it using the UP/DOWN button, which supports both short and long presses;d. To set other parameters, repeat steps b) and c);e. After all parameters are set, long-press the SET button to exit and save.Material: ABS, Package Contents: 1 * Blue.Note: 1. Due to differences in monitors and lighting effects, the actual color may be slightly different from the image!2. Please allow a 1-3 cm deviation due to manual measurement!