TEAM | Tshwane University of Technology Solar Team
CAR NAME | Sun Chaser III
COUNTRY | South Africa
CLASS | Challenger
The Tshwane University of Technology (TUT) team competed in the Sasol Solar Challenge for the fourth time in 2018.
Their new car, Sun Chaser III, was substantially different to the 2016 car, which did a total distance of 2 200km. The team worked 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 was replaced with aluminium and carbon fibre. The two motors were replaced by a single, more powerful motor, which cut 20kg off the weight of the car. Even the electrical system was refitted with lighter wires, and a number of components were removed, shaving another 5kg off its weight.
To test the aerodynamics, TUT had built a 3:1 scale model of the car and tested it in the University of Southampton’s wind tunnel in the U.K. Based on these results, the designers reduced the openings of the wheel arches, changed the cars wing shape, and crafted the cockpit canopy in the shape of a teardrop.
Top of the range Michelin tyres which were imported from France helped reduce friction on the road.
The TUT team was proud to have done the majority of their own design and manufacturing on site, however, the solar array, electric motor and charge controllers were specially purchased. Sun Chaser III had 257 mono-crystalline solar cells that made up its solar array.
To prevent the entire array from shutting down when a single cell was in the shade of a tree, a passer-by’s hand, or its own cockpit, TUT included bypass diodes in parts of the array so that sections would operate independently.
For the first time in 2018, the chase car - which followed behind the solar car when it was on the road - sent 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 the 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.
In the local battle, Tshwane University of Technology's Sun Chaser 3 finished an impressive 2,397 kilometers. TUT's solar team also experienced a tough first day, with their solar panel blowing off on the road to Kroonstad and having to be significantly rebuilt.