The article investigates power losses caused by aerodynamic forces in a stand-alone photovoltaic generator. The generator is designed to meet electrical energy requirements and is propelled by 3000 W electric motors in the rear wheels. To overcome resistances, including the variable air resistance at different speeds, the propulsion system is utilized. Numerical methods are employed to investigate the interplay between structure, shape, and performance. The contrast in pressure between the front and back of the generator creates a significant amount of pressure, mostly caused by aerodynamic drag. This occurrence is dictated by the body’s shape being examined concerning the airflow while in motion at a designated velocity, ascertaining the air’s force and dynamic pressure. During changes in speed, power is dissipated. The purpose of this study is to determine the value of this power. Numerical and analytical models provide results for this physical phenomenon. The findings of numerical simulations, which used ANSYS 2020 R1 and SolidWorks 2020 SP5 software, concerning the airflow over the generator are presented. The numerical and analytical methods show only a slight difference; 4.22% for drag force and 6.10% for dynamic pressure. These results indicate energy losses due to air resistance, revealing that a speed increase of 3 km/h results in a power decrease of 12.69 W, with rolling resistance being taken into account. It is worth noting that the total power lost amounts to 1438.55 W.