Nexergy has completed a portable power system for an unmanned aerial vehicle (UAV) for the military/aerospace market. The high-reliability solar-and-battery-powered system, developed in conjunction with SION Power, utilizes SION lithium-sulfur (LiS) battery cells in a custom battery pack assembly complete with a sophisticated charging circuit developed by Nexergy.
The UAV is designed to stay airborne for months at a time at altitudes exceeding 50,000 feet. Nighttime flight must be fully battery-powered. In initial test flights, the portable power system increased the UAV’s battery-operated flight time by 80%. The engineers had to develop a “step-charge” system that would vary the amount of charge based on the power being supplied by the solar cells, leaving enough power to drive the UAV motors. This was essential to the design solution, since the solar panels not only charge the batteries, but also power the motors during the day.