Abstract: A portable battery charger having at least one charging pocket for recharging a battery pack mounted on a mobile station or a separate battery pack, comprising a charger housing including a pair of inside walls facing each other, a ceiling connecting the inside walls, at least one opening side, a mounting space enclosed by the inside walls and the ceiling, and a printed circuit board providing at least one pair of electrical contacts; a charging unit having front and rear surfaces, a pair of side surfaces, and at least one top surface detachably mounted in the mounting housing for independently recharging the mobile station while traveling; a guide structure for horizontally or vertically mounting the charging unit in the charger housing; and an electrical connection device for electrically connecting the charging unit with the charger housing.