12 V automatic charging power control protection board automatically charge when the battery voltage drop to about 10.5 V (low voltage adjustable) , and shut off when the power is about 14.4 V (adjustable). Red light on when charging, off when fully . Relay disconnect and 220 V input end charging, thereby save energy. Assembled with special voltage control IC and special automobile relay. Small volume and large current. Voltage shutoff accurate and stable. Complete functions and reliable performance.Automatically charge and shut off. Connect any wire of 220 V with the COM port of relay, and connect charger with OFF port. The charger must be full bridge rectified output. The DC output voltage can be between 13.8 and 14.8 V. Charging test for the first time: battery voltage should be about 10 V. Function 1: Current cannot be larger than 10 A. Function 2: The board has reverse connect protection function. There is no output if no battery is connected. No output if the polarity of battery is wrong. Output short circuit automatically shut down: It is a practical protection. As long as the output short circuit, the charger automatically shut down output, so the charger from burning. Color as shown Material: pc+ metal Package Contents: 2 * 12V Battery Automatic Charging Controller Module 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.