Day Three: More than Halfway There!
Principia Solar Car Team
Hello, Solar Friends!
We began this race just 12 degrees south of the equator in Darwin, and we have now traveled more than halfway to Adelaide, through Alice Springs and across the Tropic of Capricorn. The weather is telling; the humidity has vanished, and the chill of the nights and early mornings ensures us that we’ve left the tropics.
Day three of racing has come to a close after 565 kilometers (about 350 miles) of driving by Justin and Tom. We began the day perfectly on time, leaving our campsite at precisely 8:00 a.m., and our stops throughout the day continued with similar efficiency.
Our first Control Point was Barrow Creek, a gas station and pub about 130 km into our drive. On the way up the track a few weeks ago, Joe, Steve, and I stopped at Barrow Creek for lunch one afternoon. Along with the best Australian cheeseburgers we’d ever had (topped with bacon, barbeque sauce, a fried egg, beet root, and pineapple), we got an earful from the Barrow Creek pub owner, Mick, about the money papering the walls of his pub.
In the 1960s, the story goes, cattle drovers were paid once a month, and they often spent all their money very quickly. To ensure that they would have enough cash for a drink as they were passing through town, these drovers began to leave money at the pubs – bills with their names written on them tacked to the wall. Over the years, the walls at Barrow Creek have been covered with bills – both Aussie and foreign – from passersby who’re continuing the tradition.
When Joe, Steve, and I arrived, Mick told us this story and showed us all of the American money taped to the walls. He also produced from beneath the bar his collection of United States quarters. He had collected 25 of the 50 states so far, and he laid them out for us one by one, proudly pronouncing the name of each state he had collected.
He didn’t yet have the quarters for either Illinois or Missouri, and he had never heard of an American $2 bill, so we left Barrow Creek a few weeks ago with a mission, and we made a few phone calls. Last week, Katie Farquhar, the team’s business manager, brought with her from the States 11 new state quarters and a crisp $2 bill for Mick from the Principia Solar Car Team. We signed our team name on the bill and gave it, with the quarters, to our scout vehicle to gift to Mick when they arrived ahead of the caravan. Mick was delighted, and we heard him bragging later to some patrons at the bar about having 36 of the state quarters! It was a heart-warming interaction we won’t soon forget.
While scout was taking care of business with Mick inside the pub, the team was pausing to charge the array outside. Technically, Barrow Creek was only a 10-minute control stop, but we’d been having some trouble with one battery module dipping to lower voltages than all the rest, so some directed charging for that module was needed. We took about 30 minutes total in Barrow Creek, then hopped back on the road at full speed.
A couple hours later, around 12:30 p.m., a wire in the battery pack
broke loose, and we had to make an emergency roadside stop. A closer
inspection revealed that it was the same problem we encountered
yesterday with a loose sense wire. These little wires are connected to
every module in the pack, and they are responsible for monitoring the
voltages, etc. for each module. As a whole, our pack is only as good as
the highest high voltage and the lowest low voltage. If a single module
steps outside a certain range, the battery protection system limits the
entire pack to keep things safe. With a sense wire knocked loose and the
voltage for that module unknown to the battery protection system, it
defaulted to safe mode and shut the car off.
We encountered this problem twice today (both before and after the
30-minute control point at Alice Springs) and once yesterday for
different modules. I reported last night that such issues were results
of the newness of our pack, thinking it needed a good shakedown for the
new connections. As it turns out, though, that analysis was incorrect.
While the cells and soldered connections in the battery pack are brand
new, these sense wires were borrowed from the old battery pack, so the
wires themselves have become fatigued and weak.
In order to fix the problem more permanently, Tom and John are performing major battery pack surgery tonight to replace the sense wires and reinforce the connections between battery tabs. Now you may remember I also told you about sealing the battery pack during scrutineering to prevent tampering during the race. Before we changed anything within the pack, we had to check with race officials to make sure we were within the regulations. Officials ruled that fixing these connections and replacing sense wires was acceptable battery work since it did not include replacing or charging any of the battery cells. That’s good news for us since it means we can fix our pack, but it might be a long night for John and Tom.
When we weren’t making quick fixes in the battery pack, we were traveling at a reasonable speed down the highway, often running between 95 and 100 kph (around 60 mph). We did pass the Australian team Sunswift early in the day, as we predicted, but they passed us right back about an hour later. Late in the afternoon, we breezed past the Dutch team Twente broken down on the side of the road. At the end of the day, we’re unofficially back in 6th place, having moved up from yesterday’s 7th.
The team is still working well together, and our control points and
roadside stops are getting more and more efficient. We should pass
through two more stops tomorrow, Kulgera for 10 minutes and Coober
Pedy for 30. At this rate, we should make it into Adelaide on Friday
afternoon. Stay tuned to these emails, our website
(www.principia.edu/solar),
and Principia Internet Radio (every
afternoon at 3:30 Central time) to keep up with our progress!
Cheers,
Karen
P.S. There are new pictures on our website! Check them out at
www.principia.edu/solar.
Principia College Solar Car Team
618.374.5290
www.principia.edu/solar