Saturday addendum: MIT qualified. Faster than us. Considerably faster than us. They run the qualifying lap without their array on, and they fair hoon around the track. All cheer as their driver passes through the straight; as he completes his timing lap, he punches his fist to the sky. I stop by to see if they need any help; they don't, but we do loan them a 240V soldering iron and 240V extension cable. Their array has a bad case of road rash, but they are testing it, and some of the strings are still working.
- - -
The alarm is set for 5am, because the WSC requires us to be on the starting grid by 6am. We load cars in the dark. We trailer the kilometre or so from the Alatai to our marshalling point. We're late, but we're still nearer to the front of the crowd of arriving teams than we are to the back. MIT give us our soldering iron back. They've put tape over dead cells on their array, with little messages like "You should see the other guy's car!", and "Our driver is from Harvard."
The start line is at a different spot this year: it's on the paved area in front of parliament. We queue, and get directed to a spot in the parliament house car park. In the shade. The sun is barely over the horizon, but it's easy to see that our bay will be shaded by a largish nearby building (the Supreme Court?) for quite some time. We are somewhat annoyed by this; it is our present belief that our batteries are not quite full, and we were hoping to top off in the hour or so that we are required to sit doing nothing.
A few interested people wander by and ask questions. We wonder how many more people the race start would attract if it were an hour or two later in the day.
Channel 10 stop by and interview me briefly.
Our observer, Sidd, arrives. We stand around. We field a few questions.
Our support vehicles arrive. Our lead and follow vehicles are required for the start, but they are marshalled in a separate carpark, to join us a few metres after we start the race. They bring me some Chux; I clean the array.
The race starts. Cars are brought up to the square in front of parliament at one minute intervals. Chris Selwood, the event coordinator, says a few words about each one, the flag drops, and the car is away. We are 19th off the grid.
We were required to turn up to the grid with our driver and one other person (which is me). There doesn't seem to be any guidance as to when that additional person is supposed to separate from his car -- other cars seem to be coming to the line alone, their additional person having somehow spirited themselves away to a support vehicle, but I stick to my car like glue, walking within a pace of it. We are marshalled into the centre of the square, Chris says some words about us, the flag drops, and we're away. The path from here to the road is guarded by barricades, and there is a substantial crowd behind them. We proceed at a walking pace to the road, whereupon I run for the follow vehicle. We merge up, and proceed down Mitchell Street, and turn right onto to Daly Street, which is the name for this stretch of the Stuart Highway. This is a bit odd: we've missed out the first block or two of the Stuart Highway, meaning that the race will run almost, but not quite, its full length.
The first two or three traffic lights are held at flashing amber for us, with police directing us through. After that, though, we're in general traffic, and we have to stop at lights. Several times we get separated across intersections, and the lead vehicle has to wait for the light to change before we can catch up.
Telemetry range is shocking; we are only getting telemetry when we are nosed right up behind the solar car at a red light.
The first checkpoint is Katherine, 318km away. The listed close time for the checkpoint is 4pm, so we must be there by then. That's an average speed of 43km/h, and we figure that with traffic lights and driver changes and so on, we'll need to cruise at something like 48km/h. With our new battery pack, larger than the one in Sungroper 1, we figure we can make it.
We cruise out of town. We are passed by several Greenfleet vehicles. (Greenfleet is a demonstration class, held over nearly the same route as the solar race, and at the same time.) Some distance along, we pass the French team, Jules Verne.
We continue to cruise. We're pulling an unsustainably large current, but a bit of maths suggests that the battery pack, rated at about 40 Amp-hours, should last.
We driver-change; we driver-change. With the third driver in the vehicle, we lose radio communication with the driver. It turns out to be a flat battery. This also turns out to be the reason that the telemetry range is so bad: the telemetry receiver's 9V battery is at about 6V.
The car is going slower and slower. We find a place to pull over, give the driver a new radio, and continue driving.
We ask the driver to turn up his speed a little; he replies that the throttle is already at 100%. We've just recently replaced the battery on the telemetry receiver, and we spot the out of place number: our 120V battery pack is sitting at about 90V.
We get the convoy off the road. We leap out and pop the array off, and look at the batteries. It is as the telemetry suggests: they are empty. We do some tests to find out if perhaps one third of our battery pack is simply not connected; this is not the case. We've taken about 18Ah out of our 40Ah pack, and it's simply empty.
We don't know why. We thought it was nearly fully charged before the start of the race. We know we had it fully charged a few days ago, because we got a substantial thermal rise out of it: we kept charging it off the sun after it was full, and it got to about 60 degrees Celcius. But these cells shouldn't get damaged until at least 80 degrees.
We continue solaring at a much lower pace, putting as much current out into the motor as we are getting in off the sun, slowing down for uphills and clouds, speeding up for downhills or sunny skies. We get passed again by Jules Verne.
There is much discussion via radio. Eventually, we decide to continue solaring to Hayes Creek Roadhouse, just a couple of kilometres short of the much-feared Hayes Creek Hill, and trailer from there to the Katherine check point, just before its closing time. We do so. Team Heliodet solar past the roadhouse five minutes after we leave.
We reach the Katherine checkpoint a few minutes after four. The checkpoint's closing time has been extended by an hour, because of the cloudy skies; so we discover that we actually made it with 50 minutes to spare.
We are permitted to keep solaring until 5:20pm today, because we did not cross the start line until 8:20am. But after being held at the checkpoint for the mandatory half hour "media stop" (presumably some of the front-runners see media at these stops, but we never do), we'd only get another 40 minutes of solaring, in marginal light, so we elect to simply leave the array on the side of the trailer, facing the cloudy sunset.
At dusk, we adjourn to the budget cabin accommodation.
Now that we have trailered, we are out of the lead pack of the race, who will complete the whole course on solar, and into the trailer pack. Our objective now is to complete as many kilometres as possible under solar power.
-- Doug Burbidge
