Wireless binaural hearing device system with adaptive control of transmission voltage

A system includes: first and second hearing devices, each hearing device comprising an output transducer, a wireless communication unit, an antenna, and a power supply having primary and secondary voltage sources, wherein the secondary voltage source provides a lower voltage than the primary voltage source; and a detector arrangement to provide a quality indicator indicative of a quality of a wireless link between the first and second hearing devices, wherein each of the first and second hearing devices comprises a control unit configured to operate the respective hearing device in: when the quality indicator is above a threshold, a first power mode in which the respective hearing device uses its secondary voltage source to drive transmission with its antenna, and when the quality indicator is below the threshold, a second power mode in which the respective hearing device uses its primary voltage source to drive transmission with its antenna.