Solar charge-consumption parity in multirotor UAVs: a reproducible simulation study

Abstract

Solar power has enabled multi-day continuous flight in fixed-wing unmanned aerial vehicles (UAVs), and it is natural to ask whether the same approach can free multirotor UAVs from their short endurance. This paper tests that question with an open, reproducible energy-balance simulation. A 24-hour model couples a clear-sky solar resource model, a photovoltaic panel model, momentum-theory hover power for a quadcopter, and a battery with charge and discharge losses. For a reference vehicle (3 kg quadcopter, 1 m2 of panel at 22 percent efficiency, 500 Wh battery) flying continuously at 100 m over Dhaka on the summer solstice, the model harvests 1567.3 Wh against a flight demand of 6612.8 Wh, a net deficit of 5045.5 Wh per day. A parity solver shows the solar input would have to be multiplied by 4.22 to break even, equivalent to about 4.2 m2 of panel on a 3 kg quadcopter, or a physically impossible 93 percent panel efficiency at 1 m2. Sensitivity analysis shows the deficit is structural: battery size does not change the daily balance at all, halving vehicle mass still leaves a deficit, and no latitude or season closes the gap. The conclusion is that charge-consumption parity is not reachable for small solar multirotors with current photovoltaic and battery technology, and that the realistic role of solar on multirotors is partial endurance extension, while the larger near-term gains lie in autonomous energy management. All code, parameters, and figures are released under an open license with a citable DOI so that every number in this paper can be regenerated.