Experimental Evaluation of a PEM Fuel Cell and Li-Po Battery for UAV Power Systems under Static Bench-Test Conditions

Nowadays, Unmanned Aerial Vehicles (UAVs) increasingly support applications in surveillance, logistics, and environmental monitoring, yet their operational capability is fundamentally restricted by the limitations of onboard energy sources. The commonly used lithium-polymer (Li-Po) battery provides low energy density, voltage degradation under various loading conditions, and short endurance, typically limiting the flight duration to approximately 12 minutes. Hydrogen PEMFCs exhibit higher energy density, stable voltage outcomes, and sustainable operation, making them a suitable alternative for long-endurance operations. To examine this inherent property, a 300 W air-cooled PEMFC is integrated into a 450 mm quadcopter test platform and experimentally evaluated under controlled static (non-flight) bench-test conditions at different electrical loading levels, and its performance is compared to a conventional power source. During the bench-scale UAV evaluation, the regulated UAV power bus maintained a stable output voltage of approximately 12.5 V with a current below 4.6 A, demonstrating stable power delivery to the propulsion system. The fuel cell polarization curve shows that voltage reduces from 35.6 V to 32.2 V as current magnitude increases, while power output reaches approximately 14 W. In contrast, the Li-Po battery provides a 0.8 V voltage drop during operation and significantly shorter endurance. During 30-minute operation, the stack temperature increased from 25 °C to 40 °C, indicating stable thermal operation. Comprehensive analysis shows that fuel cell stacks provide better voltage stability, constant power delivery, comparatively stable electrical performance relative to the Li-Po battery, ensuring that it is suitable for potential for long-duration operation UAV operations and improved operational reliability.