Twice Around London – Without Recharging

Dean Sigler Electric Powerplants Leave a Comment

On May 27, Imperial College students driving their electric race car around the M25 orbital road that cirles London looked more like ninja thieves (because of headgear that protected them from early morning breezes) headed toward a convenience store than serious test drivers, but their mission was far more benign than their appearance.

Their mount, a white and green two-seater that looks more destined for LeMans fame than for ecological breakthroughs, was the RGE (Racing Green Endurance) based on a Radical Sportscars SR8 chassis. Its power comes from two Evo-Electric motors each with a motor controller, propelled by a Thunder Sky 56 kWh battery pack and monitored by a National Instruments CompactRio unit which combines management of the motor control function, battery management system, and driver interface. RGE is capable of 200 kilometers per hour top speed (124 mph) and 400 kilometers (268 miles) range. The motors are light weight “pancake” type units with a power density of 4.2 kilowatts per kilogram, worthy of attention by the aeronautically minded.

Last year, a Tesla Roadster had made one lap of the M25 (184 kilometers, or about 115 miles) on a single charge, and the students were committed to doubling that. This is all in preparation for a 26,000 kilometer (16,000 mile) trip along the Pan-American Highway in July, running from the northernmost driveable point in Alaska to the southernmost point in South America. Since they used only 42-percent of their total charge on the first lap, they elected to go for a second. With the sun coming up, the drivers were able to shut off their headlamps, saving the equivalent of about 1kWh of energy.

The team’s enthusiasm is almost hyperbolic compared to stereotypical British stiff-upper-lip reserve. “Early in the morning we arrived back home in West London – a round trip of 264 miles on the car odometer and the energy meter still at 14% full. This is slightly longer than the map suggested, probably due to the fact that our west London base is more than the 10 miles estimated away from the M25! And having done this at motorway speeds without recharging the pack with a single electron! This is a FIRST for electric vehicles and another important milestone in the bag for the project. The fact that we had so much left in the “tank” afterwards didn’t really provide for a very tense and nervy finish as I had imagined it to be. Anyhow, we have definitely fulfilled the design brief in building an efficient highway cruiser for a long distance endurance trip!”

Imperial College has been featured here before, with a February 12 entry, “Structures as Batteries – Or Is It Batteries as Structures?” detailing the work to use carbon-fiber structures as energy storage systems.

Another Tesla Roadster has since gone on to accomplish a record of its own, cruising 313 miles across part of the Australian outback last October without a recharge.   The previous record, set on October 3, 2003 by the T Zero roadster developed by Alan Cocconi and driven by Tom Gage, was 302 miles without charging, at an average speed of 58 mph, between Sunnyvale and Santa Barbara, California

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