After a string of European solar-car startups went bust, two Chinese suppliers are betting that solar panels on a car's roof can earn their keep in a different way: by powering the electronics that keep draining the battery while the car is parked.
Fuyao, the world's largest auto-glass maker, has listed a solar sunroof on its website and said it is ready for mass production, according to an article on the Chinese outlet Huxiu. Around the same time, state-owned automaker FAW showed a prototype photovoltaic sunroof it calls "passive recharging," aimed at keeping the cabin ventilated, running the refrigerator and supporting sentry mode.
Why European solar cars failed
The European attempts were focused on using solar power to add driving range. Dutch startup Lightyear, founded by veterans of the World Solar Challenge, covered 5 square meters of a car in photovoltaic panels, tuned the body for ultra-low drag and fitted in-wheel motors. Under ideal conditions, it could add about 70 km (43 miles) of range from a day of sunshine. The car was priced at 250,000 euros (about $275,000), and the company burned through more than 100 million euros before collapsing in January 2023 when a would-be investor backed out.
Germany's Sono Motors took deposits of at least 500 euros from tens of thousands of customers for its Sion model, but ran out of money in February 2023 and scrapped the car. It pivoted to fitting solar panels on buses and trucks, then shut down on July 31 this year. The International Energy Agency later blamed the failures on endless cash burn, the difficulty of small-scale production and a poor deal for customers.
Powering the always-on car
The Chinese approach is different. Modern smart EVs never fully shut down: cameras keep recording in sentry mode, the telematics unit stays online and the GPS keeps reporting position. A test of 14 models cited by Huxiu found parked cars typically draw 1 to 3 kWh per day, with some older Tesla architectures consuming up to 7 to 8 kWh overnight.
FAW's prototype sunroof is said to generate about 400 kWh per year, or roughly 1.1 kWh per day - enough to cover sentry mode and other standby loads, though nowhere near enough to push a two-tonne car. Fuyao's promotional material focuses on dashcam power, GPS anti-theft, ventilation and connectivity.
The economics still look thin. A 1.5-square-metre solar panel on a roof, at a peak output of 150 W per square metre, can harvest about 1 kWh from three to four hours of strong sunshine - enough for less than 7 km (4 miles) of driving on a typical 15 kWh per 100 km consumption. But the Chinese suppliers are not chasing range; they are chasing the vampire drain that owners already pay for.
The article also notes that improvements in crystalline-silicon cell manufacturing, inherited from the semiconductor industry, are making automotive solar panels more practical, even if the technology is not about to eliminate the need for charging.
