A 2023 Challenger Class car (JU). Photo: Anthony Dekker
Well, the World Solar Challenge 2025 Regulations are out. In the Challenger Class (above), changes include:
- A size increase to 5.8 m long and 2.3 m wide, together with a requirement for clearing 75 mm speed humps
- A solar panel increase from 4 m2 to 6 m2, to compensate for the earlier time of the race (24–31 August)
- Battery storage down to 11 MJ (approx 3 kWh)
In the Cruiser Class (below), changes were greatly needed, and I think the regulations have improved significantly. We now have:
- The same size increase to 5.8 m long and 2.3 m wide (apart from that, there is now no restriction on solar panel area)
- A formal requirement for a luggage storage compartment, which “can accommodate two items of luggage, each 560 mm × 360 mm × 230 mm”
- Battery storage up to 55 MJ (approx 15 kWh)
- Three wheels are now allowed
- There is unlimited overnight charging (equipment is up to the teams)
- Vehicles must have at least 2 seats, and have 2 occupants while driving (driving without a passenger is forbidden; more than 1 passenger provides no advantage)
The rules are now much more like the first Cruiser Class event. The Cruiser Class is a race again, which makes it much easier to follow. There is also a much wider range of possible designs, which will please some of the teams that have long been “thinking outside the box.” However, there is still a Cruiser Class judging (details to be announced later), where “the design score for each Cruiser vehicle will provide a time advantage.”
A 2023 Cruiser Class car (Sunswift). Photo: John Inglis
Scientific Gems 