This module is an adjustable buck module, and the output voltage can be changed by adjusting the blue adjustable resistor on the module. The input-output voltage difference is 1V, and the minimum output voltage is 0.8V. IN- (negative input), IN+ (positive input), OUT- (negative output) and OUT+ (positive output) marked on the module must be connected correctly, otherwise the module may be damaged. Usage of battery charging: 1. Determine the floating charge voltage and charging current of the battery you need to charge, and the input voltage of the module; 2. Adjust the constant voltage potentiometer and adjust the output voltage to about 5V. 3. Measure the output short-circuit current with the current stop of multimeter 10A, and adjust the constant current potentiometer at the same time to make the output current reach the preset charging current value; 4. The default shipment of the charging lamp current is 0.1 times of the charging current (constant current value). 5. Adjust the constant voltage potentiometer to make the output voltage reach the floating charge voltage; 6. Connect the battery and try to charge it. Usage of LED constant current drive: 1. Determine the working current and maximum working voltage that you need to drive the LED; 2. Adjust the constant voltage potentiometer and adjust the output voltage to about 5V. 3. Measure the output short-circuit current with the current stop of multimeter 10A, and adjust the constant current potentiometer to make the output current reach the preset LED working current; 4. Adjust the constant voltage potentiometer to make the output voltage reach the highest working voltage of LED; 5. Connect the LED and test the machine. Color: As Shown Material: PC+Metal Package Contents: 1 x Battery Charging Only the above package content, other products are not included. Note: Light reflection 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.