XH-M604/HCW-M634 18650 Lithium Battery Charging Control Board DC 6-60V Li-ion Lead Acid Battery Charge Protection 12V Digital Voltmeter. This product is suitable for 6-60V battery charging control, and can be set free to start charging voltage and stop charging voltage! In the IN input charger 660V voltage, in the OUT terminal battery, for example, set 12V start 15V stop when the voltage is below 12V when the relay is closed to the charger charging voltage to the battery when the charge voltage is greater than 15V Relay off to stop charging, can be used in household chargers, solar, wind turbines. Use: In the set voltage value, the start button play button raised, about stop button role to down key 1. Set the start voltage: Normal display voltage state, press a starting voltage button, to display the start charging voltage. long-press the start button, digital flashes, by start and stop button, set the start charging voltage value. 2. Set Stop voltage: Normal Voltage normal display mode, press a Stop voltage button, to display the Stop charging voltage. long-press the Stop button, digital flashes, by start and stop button, set the Stop charging voltage value. 3. Setting Error: Energized state while holding down the start/stop button, digital display 888, which is the factory setting