Student-built EV crosses 3K KM in Australia to win 2025 Bridgestone World Solar Challenge

A student-built solar car from Hong Kong has beaten the odds to take top honours at the 2025 Bridgestone World Solar Challenge, the world’s toughest test for solar-powered vehicles.

The Sophie 8X, created by the Vocational Training Council (VTC), crossed the finish line in Adelaide after a 3,000-kilometre trek through the Australian outback, showing how far efficiency and innovation can take electric mobility.

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Engineering the Win

The Sophie 8X completed the journey in 44 hours, averaging 68.7 km/h across 3,021.5 kilometres. The challenge demanded not only speed, but also flawless energy management under extreme conditions.

Distance covered: 3,021.5 km
Average speed: 68.7 km/h
Race time: 44 hours

Despite fierce competition, Sophie 8X edged out Estonia’s Solaride III Enefit by just four minutes. Italy’s Onda Solare followed in third, with strong finishes also from Taiwan’s Apollo IX Plus and Australia’s Sunswift team.

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How It Stands Apart from Consumer EVs

The competition highlighted the contrast between purpose-built solar racers and today’s road EVs. While consumer favourites like the Tesla Model Y weigh around 1,900 kilograms, solar class entries typically come in between 400–800 kilograms.

Sophie 8X VS Tesla Model Y

Vehicle	Battery Capacity	Battery Weight	Vehicle Weight
Sophie 8X	15.2 kWh	40 kg	400–800 kg
Tesla Model Y	60+ kWh	770+ kg	~1,900 kg

The Sophie 8X’s roof holds six square metres of solar cells, which directly power the car and recharge the battery. Lightweight lithium pouches with an energy density of 400 Wh/kg keep weight down while delivering impressive range.

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Innovations That Made the Difference

The 2025 design marked a major leap forward for the VTC team:

In-wheel motors: New permanent magnet synchronous motors built with Guangdong partners were 18% lighter than in 2023.
Next-gen controller: A third-generation silicon carbide (SiC) unit improved efficiency, reducing consumption by up to 30% at 100 km/h.
Aerodynamic body: A carbon fibre shell, refined with CFD modelling, helped cut drag while optimising energy use.

These upgrades gave Sophie 8X the efficiency edge needed to outlast rivals across long stretches of the Stuart Highway.

From Track to Road

One of Sophie 8X’s most remarkable achievements lies beyond the race. The vehicle is legally authorised for public roads in Hong Kong — a rare step for a student-built solar car.

Event ambassador Chris Selwood summed up the progress:

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

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Key Takeaways

Sophie 8X won the 2025 Bridgestone World Solar Challenge, completing 3,021.5 km in 44 hours.
Lightweight design is the core advantage, with Sophie 8X weighing less than half of mainstream EVs.
Efficiency upgrades — including lighter motors and SiC controllers — cut energy use by 30%.
Solar integration (six square metres of cells) allowed sustained performance in the outback.
The car is road-legal in Hong Kong, signalling real-world potential beyond the competition.