Hello, Solar Friends!

Our team here in Darwin has more than doubled since the last update! On Sunday, our documentary team, Nick and John from Nick Mollé Productions, arrived and began following us closely, camera in hand.

The rest of our student team arrived today (Monday): Seniors Mark Evans, Katie Farquhar, and Justin Sinichko; Junior Brian Kamusinga; and Sophomores Megan Brown, Kendall McMurray, and Ross Vincent. They came in around noon, but most of their luggage won’t make it until 9:00 tonight, unfortunately. After more than 24 hours of traveling, this resilient team came directly to the shop and jumped into the work. We’re grateful to have their help and happy that the whole team is together again.

Brian’s journey isn’t over yet, though. As a Kenyan citizen, Brian has a complicated process of visa applications to complete so that he can re-enter the U.S. after the race. Around midnight tonight, Brian will turn around and get back on a plane to Melbourne, one of the few cities in Australia with a U.S. Embassy, where he can accomplish that application process. Then he’ll fly back to Darwin to rejoin the team on Tuesday. Whew!

The last addition to our team is recent alum Sten Palmer, an Australia native, who flew into Darwin today to work with the team for a few days. As a student, Sten was a dedicated solar car team member, and she has been a valuable contact in country in organizing many details for this race.

Work in the shop has continued as expected. Most of the mechanical maintenance has been completed, and the body work is progressing quickly. We have also finished repairing the array after the crate shelf collapse crushed a few of our fragile solar cells in shipping. We were able to peel off the two broken cell modules and replace them with spares in no time at all. We didn’t have the right wire to connect the new modules into the array, but we traded a handful of zip ties to a Canadian team who needed them, in exchange for the lengths of wire we needed to finish the array. Now, you can’t even tell we made a change! But to see pictures of the whole process, check out our new photo album, Getting Ra 7 Ready.

After long hot days in the shop, we like to joke about Tom, Matthew, and John spending their days relaxing by the pool and in the air conditioned apartments (and some of the officials at the track have joined us in teasing “those electrical guys” about their mysterious work away from the shop), but these guys have been working around the clock to get our batteries ready to race. Most of their effort has gone into perfecting the Battery Management System, particularly its interface with the telemetry system. All of this electrical jargon is pretty puzzling even to long-time team members, so I asked Matthew Piatt to explain it for me in the simplest of terms. Here’s how he broke it down.

During the race, the strategy team in the chase vehicle processes data received from the car’s telemetry system, and other external factors like the weather and the terrain, to determine the car’s optimal speed to drive as far and fast as possible using as little energy as possible. The telemetry data they use informs them about the motor controller, various physical forces acting on the car, GPS data, and, most importantly, the batteries. The battery pack is monitored by a Battery Protection System (BPS), which shuts off the car when the batteries reach dangerous levels of charge or temperature, for example. The telemetry system monitors those same aspects of the battery pack (and more) and relays that information to the driver and to the chase vehicle. The Battery Management System resides between the BPS and the telemetry system. After the BPS determines that the battery pack is safe, the BMS uses telemetry information to make decisions automatically about how to optimize battery performance on the road – decisions that used to be made manually by the strategy team in chase only when the car was off.

We might make fun of these guys for taking it easy in the air con (as the Aussies call it), but they’re creating one of the most important and technologically advanced systems on our car. So they deserve a dip in the pool.

They got that break tonight as we all relaxed around the pool in our apartment complex and chowed down on noodles and prawn crackers. We’re all feeling cheerful and rejuvenated to have the team together again, and our excitement about the race is mounting. Tomorrow we’ve scheduled a day off to sample the local Aboriginal culture at Injalak and spend more time together as a team outside the workshop.

I’ll keep you updated as we get back into the shop on Wednesday and prepare for scrutineering. And don’t forget that our first radio show is coming up soon! It will be Wednesday morning here in Darwin, but you can listen live on Tuesday afternoon, October 20, at 3:30 p.m. Central Time. Tune in to Principia Internet Radio at www.principia.edu/radio.

Cheers,

Karen

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