In this paper, a high efficiency single stage bi-directional battery charger for light electric vehicles (LEVs) is proposed. In Grid-to-Vehicle (G2V) mode, single stage operation is achieved by sharing switches between totem-pole bridgeless power factor correction circuit (PFC) and bi-directional half-bridge LLC resonant converter; in Vehicle-to-Grid (V2G) mode, by turning off the mode selection switch, the proposed topology changes into the form of a half-bridge LLC resonant converter and a full-bridge inverter. Meanwhile, the magnetic control instead of the widely used frequency control is adopted to achieve a better performance. The control circuit and EMI design is simplified, and constant frequency operation is achieved. By carefully designing resonant tank, zero voltage switching (ZVS) and zero current switching (ZCS) operation for switches are guaranteed. Experimental results about variable inductor are presented and analyzed. A simulation case is introduced to verify the feasibility and validity of the proposed topology.