The magnetic resonance coupling method is recognized as the most suitable to achieve highly efficient wireless energy transfer for battery charging. However, the performance of this method is highly sensitive to the magnetic coupling and the load parameters, whose variations cause the system to change its resonant frequency. In order to resolve the sensitivity problems of the magnetic resonant coupling in Wireless Energy Transfer (WET) systems, an effective method of frequency tuning is proposed. In this paper, the modelling, design, and implementation in a prototype of a two-coil WET system is presented. The system is keeping simultaneously the necessary data transfer between the receiver and transmitter of energy. The operation frequency of the prototype is kept below 100 kHz, while the data channel operates at 2.4 GHz. The application software which allows the tuning of the operating frequency of the prototype is specifically developed. The experimental results show that the WET system prototype together with the data transmission have the capability of tuning to the resonant frequency, or to another calculated one, allowing to achieve the best possible efficiency of the system at the energy transfer.