PrISUm II was built to compete in Sunrayce 93, a collegiate competition, sponsored by GM, EDS and the U.S. Department of Energy, to build and race solar-powered vehicles from Dallas to Minneapolis in the summer of 1993. The team from Iowa State fundraised to procure materials, designed, constructed and raced the vehicle, which placed 10th out of 34 teams.
It was powered by monocrystalline silicon photovoltaic cells, which at peak sun produced 1200 Watts, enough to power a typical hair dryer and, in this case, propel the vehicle to top speeds of 55 miles per hour. This energy went into a DC brushless motor, which was also able to recover energy from slowing the vehicle down. This regenerated energy, along with excess energy produced by the solar panels was stored in a bank of lead-acid batteries carried by PrISUm II which could then power the car when needed. The structure of the car was made from welded chrome-moly, and composite panels of aramid honeycomb sandwiched by Kevlar, giving it excellent strength with low weight.
Sunrayce 93: 10th place
Sunrayce 93 started in on June 23rd in Arlington, Texas and ended on June 26th in Minneapolis, Minnesota. PrISUm won Stage 5 of the race, finishing first in Des Moines, Iowa.
- Day 1: Sun, June 20: Start in Dallas, Texas; must reach Whitesboro, TX checkpoint; finish in Ada, Oklahoma.
- Day 2: Mon, June 21: Start in Ada, OK; must reach Shawnee, OK checkpoint; finish in Tulsa, OK.
- Day 3: Tue, June 22: Start in Tulsa, OK; must reach Miami, OK checkpoint; finish in Fort Scott, Kansas.
- Day 4: Wed, June 23: Start in Fort Scott, KS; must reach Kansas City, Missouri checkpoint; finish in Cameron, MO.
- Day 5: Thu, June 24: Start in Cameron, MO; must reach Lineville, Iowa checkpoint; finish in Des Moines, IA.
- Day 6: Fri, June 25: Start in Des Moines, IA; must reach Iowa Falls, IA checkpoint; finish in Albert Lea, Minnesota.
- Day 7: Sat, June 26: Start in Albert Lea, MN; finish in Minneapolis, MN.