RGE battery-electric racing car

The battery-powered supercar

A group of London students is driving a battery-electric racing car from Alaska to southern Argentina. E&T caught up with them in Texas.

As publicity stunts for zero-emissions engineering go, this has both style and substance: Take a hot, low-slung racing car that has no windscreen, so the driver and passenger must wear helmets; convert it to electric power using $100,000-worth of batteries; and drive it 15,000 miles from the northern tip of North America to the southern tip of South America.

Called Racing Green Endurance (RGE), the project is the brainchild of a group of engineering students from Imperial College London, all of whom have an interest in energy futures and want to promote electric motoring. It spun out of Imperial Racing Green, a college team that builds alternative-fuelled vehicles to race in competitions such as Formula Zero and Formula Student.

E&T caught up with RGE at the NIWeek developers conference in Austin, Texas, about one-third of the way through the Odyssey. After wowing the assembled developers with the car - which incorporates a CompactRIO controller from project sponsor NI - the students had a well-deserved weekend off before heading for Mexico.

'The objective is to drive the Pan-American Highway in a battery-electric car and thereby change public perception,' said Toby Schultz, RGE's chief vehicle and energy systems manager. 'If you want to change public perception, you need to get attention. If we were sensible, we'd have chosen an SUV, but, since we're not sensible...'

Team spokesman and PR director Andy Hadland joked: 'We needed something that would grab attention. It's worked - we've got pulled over 15 times so far.' He added hastily that those stops were nothing to do with speeding - most resulted from curiosity, either in the car itself or else in its British numberplate - not a common sight on US roads.

Called SRZero, the 1,100kg car was put together in just nine months. Design started in August last year, it ran under its own power for the first time in March, and it became UK road-legal in April at the first attempt. Trials then included driving two laps of London's M25 on a single charge, followed by travelling from London to Paris, again on a single charge.

It uses the body of a Radical SR8, plus a new chassis built by Radical, which is one of the project's key sponsors. To this the team added 164 Lithium Ion Phosphate batteries from fellow sponsor Thunder-Sky, giving the car 54kWh of energy storage, plus the NI CompactRIO controller.

'The NI technology is the brains of the car - it integrates all the subsystems and makes them all work together,' explained Schultz. 'It manages the status of the car, the auxiliary power, traction control, and so on. One of the subsystems is battery management; it balances the cells on charge and so on. The RIO can then take action on the battery status, for example.'

The rear wheels are independently driven by two Evo-Electric motors, so there was no need for a mechanical differential. The direct-drive motors were originally capable of 400 brake horsepower each, but were rewound to half that so that their most efficient speed matches a cruise speed of 55-60mph.

'A lot of work went into calibrating the controls and the braking so it would all feel similar to a petrol car - we wanted it to drive very similarly,' said Schultz. He added that the big difference is no gears: 'It's got nice straight flat acceleration.'

'When they think of electric cars, people still think of the GWiz not the Tesla. One of the key factors is range,' said Hadland. 'Our brief was endurance.'

The result, he said, is 'the longest-range electric car in the world.' SRZero has a range of at least 350 miles, yet costs just one penny a mile to power - and is still capable of 0-60mph in just seven seconds. The team drove some 300 miles a day in the US, although Hadland noted that they managed 430 miles in one day with an intermediate top-up charge.

As the team headed towards South America, the roads and weather made the choice of an open-topped sportscar over a 4x4 increasingly interesting. But as Hadland said, it was all part of turning battery propulsion into an adventure.

He concluded: 'The three pillars of this project are sustainability, education and adventure. It's all about trying to get kids to study engineering.'

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