On the morning of the second of the 2015 Bridgestone World Solar Challenge spirits were high on the team. We had a full day of driving with no incident, we were in the outback, and had a relaxed easy night. The Challenge was going well for us. We were able to start the day driving promptly at 08:00. We were able to drive non-stop to the next control stop at Dunmurra. We decided to spend a few extra minutes at the control stop in order to reprogram our car to allow for a pseudo-cruise control. Since Arcturus has two hub motors it is not possible to just have the motor controllers run the motors at the same speed. This is because when you turn the two wheels will have to spin at different speeds. Instead we have the motor controllers maintain the same torque for both motors and this will automatically adjust each wheel’s speed as the car turns. Our pseudo-cruise control sets a maximum torque for the motors, and this indirectly acts as a cruise control on level terrain. This was able to improve our efficiency by reducing the small fluctuations in speed that the drivers caused.

However the day did continue go this well. Early in the afternoon the driver smelled something strange in the car. The team immediately pulled over and responded very quickly and well to the possible emergency. Within thirty seconds we knew there was no emergency, and began trying to figure out what went wrong. Once we opened the car we found a wire that had shorted due to rubbing. We then had to spend a few hours on the side of the road making repairs. First we replaced the shorted wires, moved the wire so it wouldn’t rub, and added more protective nylon sheathing. Once this was repaired we found out that the short had burned out most of our Maximum Power Point Trackers (MPPT). These boards step up the solar array voltage to the voltage of the batteries and the motors as efficiently as possible. Once we had replaced and tested all of the damage boards we had just enough time to get on the road and drive a few hundred feet to a better campsite. After stopping we only needed to change out tires and make a few minor changes.

Bridgestone World Solar Challenge PRIMARY LOGO