The Realities of Using Solar Panels on Vehicles
While the idea of using solar panels to power a vehicle seems appealing, there are several technical and practical challenges that make it less feasible than it might at first appear.
Myth vs. Reality
The premise that solar panels can power a vehicle is often oversimplified. A common misconception is that these panels can generate the necessary power for a vehicle. However, the reality is quite different.
According to a simple calculation, the power generated by solar panels is significantly less than what a vehicle requires. The maximum power output from solar panels is approximately 1.5 HP. This is far from sufficient to power even a small car, let alone a larger one. Driving a vehicle involves overcoming numerous mechanical and aerodynamic resistances, which require much more energy.
Energy Requirements for Vehicle Operation
Driving a average 3500-pound car requires about 25 HP to overcome various resistances such as drive train friction, rolling resistance of tires, heating of the suspension system, and wind resistance. Additionally, a heater or air conditioner can use another HP.
To put this into perspective, 25 HP is approximately 19 kW. Under perfect conditions, with solar panels converting about 20% of available sunlight, it would take about 95 square yards of PV array to generate the necessary power. That's an array nearly 30 feet by 30 feet, which is far too large to fit on the roof of a typical car. Furthermore, the array would need to be perfectly aimed at the sun, which is impossible while in motion.
Practical Solutions
A more practical approach would be to install a solar array elsewhere and use the power to charge a battery that is then used to drive the vehicle. This method allows for a solar-powered vehicle to be more feasible and efficient.
Fortunately, there are already examples of companies working on this solution. For instance, Lightyear has developed vehicles with integrated solar panels, such as the Lightyear 0 and the Lightyear 2. These models use their solar panels to extend driving range, but they still rely on a large external solar array or a power grid for the majority of their energy needs.
Rooftop Solar Panels and Vehicle Design
Even with advanced solar technology, the rooftop of an electric vehicle (EV) is typically too small to generate a meaningful amount of energy. While a rooftop array might be sufficient to power basic vehicle features like the audio system, it is not enough to power the entire car, especially during extended driving.
In conclusion, while the concept of solar-powered vehicles is promising, the current technology and practical limitations make it difficult to completely power a vehicle solely with solar panels. Using solar power in conjunction with electric batteries and external charging methods provides a more realistic and efficient approach.