In certain high-altitude regions of China, harsh climatic conditions pose significant safety risks for manual inspection of equipment. To address this challenge, small unmanned aerial vehicles (UAVs) can be employed for remote inspection tasks, thereby enhancing both operational safety and efficiency. This study focuses on the design and optimization of the UAV energy system, utilizing a hybrid power supply scheme based on photovoltaic (PV) panels and battery storage. Given the strict lightweight requirements of UAVs, and considering practical operational scenarios and load demands, a real-time energy management strategy based on logical rules is proposed. To achieve a lightweight energy system, a particle swarm optimization (PSO) algorithm is applied to determine the optimal series-parallel configuration of PV modules and batteries under given constraints. The result is an optimized configuration scheme that enhances the performance and feasibility of the UAV energy system.