A socket, a battery weighing almost half a tonne and 200 kilos of dry ice every day in the box at the race track. These are some of the features that have emerged with the rise of electric racecars, and the new models have completely changed the way racing teams do their work. CUPRA engineer Xavier Serra, mechanic Jordi Martí and race driver Jordi Gené explain the keys of this transformation during a day of testing with the e-Racer.