In this paper, we exploit an Unmanned Aerial Vehicle (UAV) as a data collector which first transfers wireless energy to an Internet of Things (IoT) node who then sends back the data packets to UAV. In particular, we present a resource allocation scheme for the data acquisition task by minimizing the overall energy consumption. We further investigate two optional allocations for wireless energy transfer time and data transmitting power as well as the applicable conditions. Numerical results show the adaptability of our allocation scheme with the varied value of channel-fading parameter and data size level.