We check it's the right type, model, brand, design. Then we check if the right number of cells in the battery, they're not slipping one or two extra ones in. Because we don't want teams swapping batteries and cells in and out all the time because they will be charged from the mains and this is a solar powered race. But the most severe restriction is the size of the solar panel. That's why they call this a challenge, not a race.
Solar cars are electric cars, they just make their electricity from the sun.
All the working parts of these cars, developed especially for this race, will run the battery-powered electric cars that Honda, Nissan and Toyota expect to market within the decade. We may have a couple of decades' or half a century's supply. Either way these children will live to see it run out. This race has pushed solar panel technology forward by decades. When you're driving on an energy source as diffuse as sunshine, every bit has to count.