Caterham, the iconic British sports car manufacturer, is set to unveil two prototypes of an electrically powered Caterham Seven sports car at the Goodwood Festival of Speed in July. The cars are designed to match the 3.4-second 0-62mph performance of a 237bhp Seven 485, with enough battery power to perform flat out on track for 20 minutes and be able to fully recharge via a 150kW charger in just 15 minutes. The prototypes have been prepared by British Touring Car Championship engine builder Swindon Powertrain and are part of Caterham’s preparation for where legislation or parts availability might take it.

Caterham CEO Bob Laishley told Autocar that the electric prototypes feature a wide-bodied latest-generation Seven chassis, with the engine and transmission swapped out for a 50kWh (38kWh usable) battery. Elsewhere, a 322bhp electric motor and limited-slip differential are packaged where the boot would usually be and incorporate a Seven’s de Dion rear suspension. The biggest aim is a 150kW charge rate, which, Swindon says, is feasible because it has dielectric fluids cooling the battery pack.

Creating an EV that can cope with the demands of a race track in a lightweight sports car form “is the complete opposite of what everyone thinks about making EVs” and is one of the hardest use cases to develop. The pack is the “lion’s share of development” and heat management is the challenge. The system is a “slight evolution of what we have on the shelf”, said Swindon managing director Raphaël Caillé, and Caterham has come “with an aggressive target weight”.

Overall, the electric Seven tips the scales at 701kg, up from the 626kg of the petrol Seven 485 – or about the same as carrying a passenger, said Laishley – and the prototype will not have its own on-board charger. “We wanted to build a car to give us the best chance to match something we produce today as a reference,” said Laishley. “We ballasted [a 485 to 700kg] and drove it all day at Snetterton. I think there was a huge amount of scepticism about whether a 700kg Seven would be true to the values. Let’s say the naysayers are not quite converts but had very positive comments.” After their Goodwood debut, the cars will be used as demonstrators.

Laishley said it’s not a project that will be on sale any time soon, but added: “I don’t mind doing anything so long as there’s a business case.” The biggest challenge for track-based EVs is weight, and Caterham is keeping this simple and matching the performance of something that already exists. “We’re trying to be true to the production car,” said Laishley.

“We think a future Caterham Seven has to be able to deliver,” he added. “We’re keeping this simple and matching the performance of something that already exists. We’re trying to be true to the production car.”