Student-Built EV Wins 1,864-mile Australian Solar Race Against Global Rivals

A team of students from Hong Kong’s Vocational Training Council (VTC) has made history with their creation Sophie 8X, a solar-powered electric vehicle that claimed victory in the Cruiser Class of the 2025 Bridgestone World Solar Challenge.

The biennial competition, regarded as the world’s toughest test of solar-powered vehicles, took teams on a grueling 3,000-kilometer journey across the Australian outback, from Darwin to Adelaide. Sophie 8X completed the route in just 44 hours, covering 3,021.5 kilometers at an average speed of 68.7 km/h (42.7 mph).

Since its launch in 1987, the World Solar Challenge has drawn elite engineering teams from universities and research institutions worldwide. The extreme desert heat, vast distances, and unpredictable conditions make it the ultimate proving ground for renewable energy innovation.

This year’s event saw Hong Kong’s Sophie 8X take the Cruiser title, while the Netherlands’ Brunel Solar Team from Delft University of Technology triumphed in the Challenger Class. Estonia’s Solaride III Enefit secured second place in the Cruiser race, finishing just four minutes behind Sophie 8X. Italy’s Onda Solare, Taiwan’s Apollo IX Plus, and Australia’s Sunswift team rounded out the competition.

What set Sophie 8X apart was not just speed, but efficiency. Unlike mainstream EVs such as the Tesla Model Y, which tips the scales at 1,900 kilograms (4,200 pounds), the Cruiser-class entries are featherweights between 400 and 800 kilograms. Sophie 8X itself weighs far less than a production EV yet achieves remarkable energy output.

Its 15.2 kWh battery pack weighs only 40 kilograms (88 pounds). The car’s roof is equipped with six square meters of solar panels, directly feeding the motor and charging the battery simultaneously. The VTC team also employed 400 Wh/kg lithium battery pouches, balancing compactness with high energy density.

The Sophie 8X project wasn’t just about efficiency; it was about precision engineering. For the 2025 iteration, the Hong Kong team partnered with Guangdong manufacturers to develop in-wheel permanent magnet synchronous motors that are 18% lighter than the 2023 version.

These motors are paired with a third-generation silicon carbide (SiC) semiconductor controller, allowing for smoother and more efficient power conversion. According to team engineers, this innovation alone can cut energy use by up to 30% at highway cruising speeds.

Aerodynamic optimization was another critical factor. Using computational fluid dynamics (CFD), the team sculpted a lightweight carbon fiber body to minimize drag, while also updating environmental and road models to fine-tune race strategy.

The payoff was evident in the outback, where Sophie 8X managed to balance speed, endurance, and efficiency, clinching victory in one of the most closely fought Cruiser races in the event’s history.

Beyond the trophy, perhaps the team’s proudest achievement is that Sophie 8X is legally authorized for use on public roads in Hong Kong. This milestone means the car isn’t just a research prototype it has met recognized automotive safety standards, putting it one step closer to real-world application.

Event ambassador Chris Selwood praised the achievement: “What a credit to this team. In 2023, they finished in the non-competitive class. Now in 2025, they’ve returned to win the Cruiser Cup.”

The Bridgestone World Solar Challenge has now seen more than 10,000 participants since its inception, with teams from Stanford, Cambridge, and Tokai University among its past competitors. Each edition pushes solar vehicle technology further, shaping innovations that could one day influence mainstream electric cars.

For Hong Kong’s Sophie 8X team, this victory is not just a triumph of engineering—it is proof that lightweight, renewable, and road-legal solar cars can move from the research lab toward the streets. And with every edition of the race, the dream of sustainable, self-powered vehicles inches closer to reality.