This paper introduces a new application of wireless power transfer, enabled by our reconfigurable bi-directional wireless power transceiver chips. Here, two reconfigurable wireless power transceivers, which reuse almost all of the hardware, are briefly discussed. In particular, a novel cross-connected structure for the differential class-D power amplifier in the transmitter mode is proposed for reducing the switching losses. Fabricated in 0.35 μm CMOS process with 5V devices, over 78% battery-to-battery charging total efficiency and over 0.6A wireless charging current are demonstrated with two identical transceiver chips with printed coupling coils on board.