techniques are described herein that are capable of increasing efficiency of wireless power transfer . a wireless power transfer system includes features that allow the system to be deployed in public spaces such as airports or in commercial establishments such as restaurants or hotels to allow a user to recharge one or more portable electronic devices while away from home . to accommodate wireless recharging of a variety of device types and states , the system may receive parameters and / or state information associated with a portable electronic device to be recharged and may control the wireless power transfer in accordance with such parameters and / or state information . for instance , the system may increase efficiency of the wireless power transfer based on such parameters and / or state information . the system may also provide a secure and efficient means for obtaining required payment information from the user prior to the wireless power transfer , thereby facilitating fee - based recharging .