This product works with DJI original charger or 17.5V DC power source. Using the 1 to 3 battery charging board, users can charge up to 3 Phantom 4 batteries in one shot. With intelligent charging management, the batteries will be charged in sequence depended on their remaing power (battery with highest voltage will be charged first). Users don't need to change battery during the charging process. Estimated charging time using original charger : 60~70 minutes per one battery.