Minimizing shadow effects to optimize solar energy input in the World Solar Challenge

Abstract

Efficient energy utilization is essential for the performance of solar-powered electric vehicles, especially for achieving extended range in competitive settings such as the World Solar Challenge (WSC25). This 3,000 km race from Darwin to Adelaide, Australia, presents unique challenges, particularly regarding efficiently capturing solar energy using a 6 m2 panel area. Factors such as the type of solar cells, their orientation, and the photovoltaic (PV) arrangement in clusters mapped to maximum power point tracking systems play significant roles in energy efficiency. This study examines the shading effects encountered during WSC25 on a vehicle measuring 5.5 m in length, 1.6 m in width, and 1 m in height, with a drag coefficient of 0.0973. We assessed the impact of shading on energy generation and vehicle performance. By analyzing solar irradiance along the race route using Hotell’s clear-day model, we aimed to optimize the roof angle of the solar panels to enhance energy absorption. The vehicle was equipped with a 3.35 kWh battery and 1.32 kWh solar panels, rated under standard test conditions. We also identified areas prone to shading that may affect the overall energy yield, utilizing Blender for visualization. A comprehensive energy audit was conducted to quantify power losses associated with shading and other factors influencing vehicle performance. Furthermore, we explored potential strategies to mitigate these losses and improve overall energy input, including the use of bypass diodes in specific shadow-affected regions. Our findings show that the use of half-cut solar cells in shaded regions can enhance energy generation by 3% compared to the best-performing full-cut cell cluster under similar shading conditions. These insights offer valuable guidance for the design of solar vehicles and the development of race strategies for teams competing in solar endurance challenges worldwide.