TEAM | Tshwane University of Technology Solar Team
CAR NAME | Sun Chaser III
COUNTRY | South Africa
CLASS | Challenger
The Tshwane University of Technology (TUT) team is competing in the Sasol Solar Challenge for the fourth time this year.
Their new car, Sun Chaser III, will be substantially different to the 2016 car, which did a total distance of 2 200 km. The team has been working on the new, roughly R2 million car for more than a year, making improvements to its weight and aerodynamics.
To make it lighter, the heavy steel suspension has been replaced with aluminium and carbon fibre. The two motors have been replaced by a single, more powerful motor, which has cut 20 kg. Even the electrical system has been refitted with lighter wires, and a number of components have been removed, shaving another 5 kg off its weight.
To test the aerodynamics, TUT built a 3:1 scale model of the car and tested it in the University of Southampton’s wind tunnel in the UK. Based on these results, the designers reduced the openings of the wheel arches, changed the car’s wing shape, and crafted the cockpit canopy in the shape of a teardrop.
Top of the range Michelin tyres imported from France will help reduce friction on the road.
The TUT team is proud to have done the majority of their own design and manufacturing on site, however, the solar array, electric motor and charge controllers have been specially purchased. Sun Chaser III will have 257 mono-crystalline solar cells making up its solar array.
To prevent the entire array from shutting down when a single cell is in the shade of a tree, a passer-by’s hand, or its own cockpit, TUT has included bypass diodes in parts of the array so that sections can operate independently.
For the first time this year, the chase car - which follows behind the solar car when it’s on the road - will send optimal speed values to the solar car driver on an LCD screen on the steering wheel. In previous years, this was done over radio conversations!
Solar cars contribute significantly to global research and development of energy systems and aerodynamics, and one Sun Chaser III team member’s doctorate thesis on energy management and estimation will be informed by the lessons learnt in 2018.