March 30, 2009 A Solar car called Power Of One (Xof1) claimed a new unofficial world distance record for a solar powered car when it arrived in Los Angeles on March 6th having driven over 12,5000 miles (20,000 km) using only sunshine as fuel.
There is some debate about exactly what constitutes a Solar car world distance record. We wrote about the Solar Taxi setting the Solar car world distance record at 52,000km (32,000 mile) in December. The primary difference between the two is that Xof1 covered the entire distance with power generated by solar cells on the vehicle and has never been plugged into the power grid while the Solar taxi had a solar power plant on a rooftop in Berne, Switzerland with which they fed solar electricity into the grid and used this for overnight battery charging anywhere in the world, much like paying money into a bank account and withdrawing the money from an ATM somewhere else.
The first solar car record was set in 1982 when Larry Perkins and Hans Tholstrup drove the 4,000 km (2500 miles) across Australia from Perth to Sydney in “Quiteachiever”. That record stood till 2000 when “radiance” from from Queens University in Canada drove 7,000 km (4375 miles). The Australians retook the title in 2002 with “Aurora” and set the mark at 12,000 km (7500 miles). The Guinness World Records Longest journey by a solar electric vehicle is still held by The Midnight Sun solar car team from the University of Waterloo in Ontario, Canada, traveled a distance of 15,070 km (9,364 miles) through Canada and the United States in 2004.
The Xof1 Solar car was inspired by the Solar race cars that contest the World Solar Challenge (WSC) across Australia. The super aero shaped vehicle weighs 300kg (including the driver) and is powered by a 900 watt solar array made from 893 Shell solar cells. The car carries a 108 volt Li-ion polymer battery that can store 4 kwh while propulsion is provided by a 7 Kw (9 hp) NGM blushless DC (BLDC) axial flux wheel motor based on technology licensed from the University Northern Territory developed for the WSC. This is the same basic configuration as most current Solar Race cars.
Xof1 uses regenerative braking to extend it's range along with ultra low rolling resistance tires. These specially made tires have a rolling resistance of 2.5 kg per ton, compared to 11 to 13 for a normal car tire. This means the effort required to move a 1000 kg car on a flat surface is 2.5 kg, compared to 11 to 13 kg for a normal tire.
With a full battery the Power of One can travel 200km (125 miles) with a top speed of 120 kmh (75 mph). The cost of building the car is an estimated $500,000. The trip has been without any reported major technical problems so far and there is no reason the solar car can not keep driving, setting a new solar car record with every turn of the wheel.
Paul Evans
Best regards. Ola Gunnarsson.