Sasol Race Report #4

Here are the results for the Sasol Solar Challenge in South Africa, as at day 4 out of 8. Only the Challenger class is shown (not the car from Hong Kong, which is driving non-competitively). The daily “loops” are marked, and the photo is from here. See also the online tracker and my teams list and information page, which includes links to team social media.

Nuon had some minor technical problems today, allowing Tokai to take the lead. Nuon has some excellent videos about the race (Dutch with English subtitles) for day 1, day 2, day 3, and day 4.

I’m beginning to doubt that Central University of Technology (CUT) or Cape Peninsula University of Technology (CPUT) will ever get their cars working; but they clearly have not yet given up. In hindsight, universities offered the chance to start new teams should have been approached much earlier. However, Tshwane University of Technology (TUT) has done a fantastic repair job after the storm damage on day 1. I hope that they will be able to make it to Australia next year.

Weather forecasts for the rest of the race route are:


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Sasol Race Report #3

Here are the results for the Sasol Solar Challenge in South Africa, as at day 3 out of 8. The big storm at the end of day 1 is marked. Only the Challenger class is shown (not the car from Hong Kong, which is driving non-competitively). Black spots mark time penalties, and the photo is from here. See also my teams list and information page, which includes links to team social media.

In the Sasol Solar Challenge, teams drive a fixed route each day, with the option of detouring around a “loop” 0, 1, 2, 3, … times. These “loops” are highlighted in the chart above. For example, on day 1, Nuon and Tokai both drove the fixed route as well as driving the 76.1 km loop five times (however, these “loops” actually happen somewhere in the middle of the day’s route, not at the end).

These “loops” mean that strategy essentially becomes a version of the difficult knapsack problem. Teams must maximise the sum of the lengths of the chosen loops, subject to time and energy constraints. This is further complicated by the uncertainty of future energy input (will it be cloudy in 4 days time?) and the psychological cat-and-mouse between the leaders (something which Nuon generally excels at). It will be interesting to see how Nuon and Tokai play the strategy game over the next 5 days.

Nuon has excellent videos about the race (Dutch with English subtitles) for day 1, day 2, and day 3.

Update: NWU apparently had battery problems. CPUT is still hoping to fix their car so that they can get it off the trailer and onto the road. Days 4 and 7 will see some shorter loops, so some distance might open up between Nuon and Tokai then. Weather forecasts for the race route are:

  • Tuesday Sept 25 – Windy
  • Wednesday Sept 26 – Sunny
  • Thursday Sept 27 – Sunny
  • Friday Sept 28 – Rain
  • Saturday Sept 29 – Mostly cloudy

Sasol Race Report #2

Here are the results for the Sasol Solar Challenge in South Africa, as at day 2 out of 8. The storm at the end of day 1 (which blew tents away and damaged TUT’s car) is marked. Only the Challenger class is shown, and black spots mark time penalties. See also my teams list and information page.

Nuon has vlogs (Dutch with English subtitles) for day 1 (with the storm) and day 2.


Quick solar racing update #2

Another quick solar car racing update. Teams have been arriving for the iLumen European Solar Challenge (iESC) in Belgium, and my iESC teams list and information page has been updated with latest news.

Scrutineering and qualification for the Sasol Solar Challenge in South Africa is complete (see my Sasol teams list and information page). Online tracking will be here. The starting grid for this race is:

  1. Tokai
  2. NWU
  3. Nuon
  4. TBA
  5. TBA
  6. TBA
  7. TBA
  8. TBA
  9. TBA

Solar Car World Rankings


Nuon at WSC 17 (photo: Anthony Dekker)

Here is my personal world ranking of the top twenty Challenger-class solar cars. It was produced entirely algorithmically by using linear regression on historical data to build mappings between WSC rankings and those of other races, and then applying those mappings to the results of four recent events (SASOL 16, ESC 16, WSC 17, and ASC 18). There is as yet insufficient data to rate Cruiser-class teams (apart from the actual WSC 17 results: 1 Eindhoven, 2 Bochum, 3 Arrow).

Rank Team SASOL16 ESC16 WSC17 ASC18
1 NL  Nuon Solar Team 1 1
2 US  University of Michigan 2 2
3 NL  Solar Team Twente 1 5
4 BE  Punch Powertrain Solar Team 2 3
5 JP  Tokai University 2 4
6 AU  Western Sydney Solar Team 6 1
7 JP  Kogakuin University 7
8 HU  Kecskemét College GAMF (Megalux) 3
9 SE  JU Solar Team 8
10 US  Stanford Solar Car Project 9
11 CL  Antakari Solar Team 10
12 ZA  North West University 4 P
13 CA  University of Toronto (Blue Sky) 11
14 CA  ETS Quebec (Eclipse) 3
15 JP  Nagoya Institute of Technology 12
16 TR  Istanbul Technical University (ITU) 7 P
17 CA  Poly Montreal (Esteban) 4
18 CH  Solar Energy Racers 8
19 US  Massachusetts Institute of Technology 5
20 TR  Dokuz Eylül University (Solaris) 9

Note that, for ESC 16, the 3rd, 4th, and 5th place cars were all Bochum Cruisers and are therefore not listed here, while 6th was Onda Solare, which is now also a Cruiser team. The letter P marks cars that participated in WSC 17, but did not finish, and thus were not ranked. It must also be said that Eclipse, Esteban, and MIT should probably be ranked higher than they are here – the algorithm is not taking into account the dramatic improvement in ASC teams this year.


Michigan at WSC 17 (photo: Anthony Dekker)


ASC 18: Convoys


A typical convoy (click to zoom, photo of solar car by Jorrit Lousberg)

Solar cars in the American Solar Challenge each form part of a convoy – a typical convoy is shown above. The lead (front) escort vehicle must travel 500 metres or less ahead of the solar car, with headlights on and roof-mounted amber lights flashing.

The chase (rear) escort vehicle follows directly behind the solar car, also with roof-mounted amber lights flashing, and bearing a sign that says “CAUTION: SOLAR CAR CARAVAN AHEAD.” Both escort vehicles must carry safety equipment such as first aid kits and fire extinguishers. The chase (rear) escort vehicle typically also houses the team’s Decision-Making Unit (DMU), who plan the strategy for the race.


Left: Michigan’s lead and chase vehicles for the 2010 American Solar Challenge (credit). Right: interior of Nuon’s chase vehicle for the 2011 World Solar Challenge (credit).

The truck (or car with a trailer) rides further behind (at least 1 km). It carries equipment and provides the ability to transport the solar car in the event of a breakdown.


Left: Michigan’s semi-trailer driving down the Stuart Highway in the 2011 World Solar Challenge (photo: Marcin Szczepanski). Right: Calgary’s road crew truck from the 2005 North American Solar Car Challenge (photo: James Tworow).

The (optional) scout vehicle rides well ahead (at least 1 km), checking out road conditions and potential hazards. There may also be additional vehicles, like media cars, or a weather car watching for clouds an hour or so ahead of the solar car. All the cars in the convoy stay in touch using CB radio. It takes a whole team to race a solar car! Here are some team descriptions of their convoys:

This post has been adapted and updated from a previous one.


ASC 11: Leadership


Nuon Solar Team celebrates their 2017 WSC win (photo: Anthony Dekker)

Ernest Hemingway famously said that “war is fought by human beings.” It’s the same with solar cars – they are built and raced by human beings. Or, as Solar Team Twente likes to say, they are “powered by human energy.

There are many aspects to this human side of solar car racing. I’ve written before about how little things like team clothing contribute to team cohesion. A diversity of skills is important if a team is to succeed. During the race, nutrition is one of the things necessary to keep people working at top efficiency. But today, I want to talk about team leadership.

Engineering leadership is critically important, although surprisingly little is written about it. Tracy Kidder produced a fantastic, almost ethnographic, description of real-world engineering in his 1981 book The Soul of a New Machine, but even that book has the actual leadership happening mostly in the background.

A century earlier, Leo Tolstoy opened his novel Anna Karenina with the words “Happy families are all alike; every unhappy family is unhappy in its own way” (“Все счастливые семьи похожи друг на друга, каждая несчастливая семья несчастлива по-своему”). That is true also for solar car teams. Many things have to be done right if a team is to succeed, but doing one thing badly is enough to stop a team in its tracks.

A team leader must, first of all, motivate team members to do their best – it is no accident that all the solar car team leaders I’ve met have been really nice people. A team leader must make sure that the overall problem of building, racing, and finding sponsorship for a solar car is broken down into manageable pieces, and that the right person is in charge of each piece – this is the essence of engineering.

A solar-car team leader must also have – and promote – a clear vision of the car that the team is going to build. It is possible to have a world-class suspension, a world-class body, world-class solar cells, and world-class everything else, and still fail, because the components were designed under different assumptions, and don’t actually fit together to make a world-class car.

A team leader must keep an eye on the critical path as well. Building a solar car for a race is one of the most challenging kinds of engineering project – one where the delivery date is fixed in stone. What project managers call the critical path is the sequence of activities which, if they take any longer than planned, are guaranteed to delay project completion. Generally, the schedule for building and testing a solar car doesn’t leave much room for that kind of schedule slippage.

One perennial question with solar car team leaders is how long it takes them to realise that there is a problem requiring the team to either (a) change the way it operates or (b) pull out of the competition. Each year, I am reminded by somebody or other of Napoleon’s 1812 invasion of Russia, summarised so well in the famous data visualisation above (by Charles Minard).


Napoleon’s death march (painted by Illarion Pryanishnikov)

Napoleon began his invasion with 422,000 men, and reached Moscow with only 100,000 survivors. This was not enough to do anything, so he turned around and went home again, losing most of his remaining troops to cold and skirmishes in the process. I have often wondered at what point Napoleon realised that his plan was not working the way that it was supposed to. In a similar way, there is always a solar car team that begins a last-minute “death-march,” working until 3:00 AM each night, desperately trying to finish their car. The early hours of the morning are not a good time to be making safety-critical engineering decisions, and teams which leave it so late to panic generally don’t do very well.

But enough of Napoleon. Let us listen to some men and women who know how it’s done (translations from Dutch are my own best attempts):

Olivier Berghuis, Solar Team Twente (2017): “As team leader you are the one ultimately responsible for the success of the project. That means that you have to keep a close eye on the progress of the project’s technical, communication, and financial aspects. The mood of the team and the personal development of each team member are also critically important important responsibilities of the team leader.” (“Als teamleider ben je eindverantwoordelijk voor het slagen van het project. Dat betekent dat je de voortgang van het project op technisch, communicatief en financieel gebied in de gaten moet houden. Daarnaast is de sfeer binnen het team en de persoonlijke ontwikkeling van elk teamlid een zeer belangrijke verantwoordelijkheid van de teamleider.”)

Shihaab Punia, University of Michigan (2016): “… build the best possible team and team culture …”


Photo: Jerome Wassenaar

Irene van den Hof, Solar Team Twente (2015): “I think that I am a good listener for my teammates. I try to put a lot of emphasis on that. Everyone is young and inexperienced, and that can sometimes cause problems, but together we are indeed a team, and everyone has to reach the finish line – I make sure of that.” (“Ik denk dat ik heel goed kan luisteren naar mijn teamgenoten. Daar probeer ik ook veel aandacht aan te besteden. Iedereen is jong en onervaren en dat kan voor problemen zorgen, maar samen zijn we wel een team en iedereen moet de eindstreep halen, daar zorg ik ook voor.”)

And it’s worth repeating the excellent insights from Rachel Abril, who was on the Stanford solar car team for four years (“Go fast, but not recklessly fast. Test it. Test it again. Test it more. Use failure as a foundation for success.”):