A team of engineering students from the University of Johannesburg is putting the finishing touches to a R1m solar-powered car, ready to take part in the Sasol Solar Challenge 2014 race which takes place from 27th September to 4th October. This will be the third time that UJ Solar has entered the gruelling challenge, which sees drivers cover 260km a day to get from Pretoria to Cape Town, is by far its most ambitious yet.
Warren Hurter, a former student at UJ and driver of last year’s entry into the Sasol Solar Challenge, says that the original car designed by the team had a top speed of 60kmph. This year’s car has had to be artificially limited to a maximum 140kmph – higher than the speed limit on the public roads over which the challenge takes place.
“It doesn’t accelerate tremendously fast,” explains Hurter – who remains on the UJ team with the backing of his current employer, Resolution Circle, “But that’s just the way it’s set up to conserve battery life. If we wanted to, we could pull donuts in it.”
The new car is considerably lighter than the old one – a mere 120kg compared to 300kg for the original UJ vehicle – and is much smaller too. The 2012 car is a whopping 5.5m long while the 2014 model is just 3.6m says Hurter.
The reduction in size is largely down to more efficient solar panels, which have been supplied by sponsor Eskom as the car no longer requires such a large surface area. To get the weight down, the team has switched to a custom built carbon fibre chassis – the original car was all wood – with kevlar reinforcements around the cockpit.
More intriguingly, many of the internal fixtures and fittings – including the front part of the steering wheel have been 3D printed on consumer-grade RepRap-style 3D printers.
“The battery compartment in the original car weighed about 50kg,” Hurt explains, “By 3D printing all the mounts we’ve got that down to 20kg now.”
Despite the reduction in size, the new car is expontentially more sophisticated than the original racer, which Hurter says was little more than an engine, a seat and a mount for the batteries panels. Now, on board computers and sensors are capturing as much real-time data as possible about the car and feeding it back to the driver: everything from the angle of the sun to the topography of the road ahead is being taken into account for measuring efficiency. Ultimately, says Hurter, this is the research Eskom is most interested in.
“The system we’re using here is very flexible and can easily be adapted and used elsewhere,” he says, “We’re using it to get the most out of the car, but you could plug it into the grid.
“We often use the Formula 1 analogy. Investment in this project isn’t really about the car at all, it’s about the research that comes out of it.”
And the project has generated an enormous amount of research. Engineers on the UJ team have published an astonishing 23 academic papers in the last three years, which has direct benefits for the university’s funding. Plus, he says, taking the car itself out to schools has been a powerful tool for outreach projects and encouraging pupils to take up maths and science.
While South Africa does have a relatively well established solar industry, and two major power plants already online, Hurter says that the biggest advantage of the solar car challenge has been in developing South African technology and training local engineers – and that’s where its headline 2014 sponsor, RS Components came in.
“What we’ve done is tell them that they can have up one million rands worth of products, entirely of their choosing,” says RS Component’s general manager Brian Andrew, “It’s the first time we’ve done anything of this scale, and we want to get other universities involved too.”
Andrew says that like Eskom, it’s not the solar power side of the project that’s most interesting for RS, it’s what they can learn about energy efficiency and what’s useful from their own vast product line of components.
“Our target market is R&D engineers,” he says, “Because they’re our future customers.”
The UJ team has used its budget to build the monitoring systems from the ground up using essentially low cost electronics like the Raspberry Pi. As well as being cost effective, the Pi is also very, very low power – which is why the firm is promoting it for a lot of uses here.
“We’re passionate about the Pi in education, ” Andrew says, “And we’re looking for more partnerships there.”
RS has also helped with the 3D printing side of the project, lending its bot farm to the team as well as supplying printers as part of the sponsorship deal. Being able to build almost everything from scratch, says Hurter, has given the students and enormous opportunity to learn and build systems that simply aren’t available internationally.
While the ultimate aim for the UJ team is to compete at next year’s world championship in Australia, Hurter says this year’s race will be just as competitive and even more challenging.
“The Australian race is a lot simpler,” he explains, “Because the whole course is pretty much flat. Over here it’s very hilly and you have to contend with potholes. You’ll see South African solar cars are a lot higher off the ground than international ones. They’re like 4x4s.”
Hurter talks openly about the technology inside the car and the modifications the team has made for this year’s competition, but the one thing we don’t know is exactly what it looks like yet. The 2012 car is pictured at the top of this article, and the 2014 model won’t be unveiled until 5th August. Partly because UJ wants a big press launch, but also because they haven’t finished building it yet.
Now that we’ve heard so much about the UJ entry, we can’t wait to see the final design. And in the run up to the race itself we’ll try to interview as many of the other teams as possible too.