1. SVT
Oregon State University
Solar Vehicle Team
OSU Solar Vehicle Team

2. Background Information – Solar Cars
Solar panels directly on car
Completely enclosed system
No external energy input
Aux. battery pack to store excess energy for later usage
Solar cars mainly seen in two events
North American Solar Challenge (NASC)
World Solar Challenge (WSC)

3. Solar Car Races: NASC and WSC
World Solar Challenge
3000 km race from Darwin to Adelaide
10 day race
North American Solar Challenge
2400 mile race from Dallas, TX to Calgary, Canada
Highway format
Highway speeds, traffic
Must be street legal (auto insurance, plates, VIN, etc)
WSC

4. Solar Car Races: NASC and WSC
Fastest cars in World Solar Challenge can go faster than 142 kph
Top 2 to 3 vehicles can sustain posted speeds throughout race
NASC 2008

5. Solar Array and Batteries
6 m2 or 9 m2 solar array surface area allowed
Generates around 1800W (2.4 HP) peak with triple junction GaAs
Batteries only store 5 kWH (1.34 HP for 5 hrs)
How is propulsion possible?
Triple junction GaAs cell [2]

6. Forces and Power Balance
Pin = small, maximized
Fdrag minimized
Pout = small, maximized

7. Design Goals Efficient power input Efficient power usage
Low aerodynamic drag
Low mass

8. Efficient Power Input – Best Cars
> 26% efficient, triple junction GaAs array on fastest cars
> 98% efficiency electronics
High efficiency Li-Ion/LiFePO4 for charging and discharging.
Concentrators used on Univ. of Michigan car
U of M solar car evening charging with
concentrator sub-array

9. 2010 OSU Solar Car in wind tunnel
Lowering drag
Reduced weight
Carbon fiber
Aluminum/Titanium chassis
Most cars weigh 200 to 300kg
Better areo
Cd of .21
.741 m2 cross sectional area
Cd * A = .156
CFD/wind tunnel testing
Attention to detail – fillets, ridges
2010 OSU Solar Car in wind tunnel

10. OSU Solar Vehicle Team OSU’s first solar vehicle
First car in Northwest
$50,000 budget vs. $2.4 million of U. of Mich.
16.4% efficient cells
Brushed DC motor, 94% efficient peak (linearly decreasing to 0 as RPMs drop)
Fiberglass body
First titanium chassis in NASC history
LiFePO4 battery pack
15th out of 24 entrants

11. OSU Solar Vehicle Team (cont’d)
2010 OSU Solar Car: Odyssey
17.4% minimum efficiency mono-crystalline SolarWorld solar array
Optimized prepreg carbon fiber body
Ti-425 titanium chassis and suspension
95% efficient NGM PMAC wheel motor
0.21 Cd drag, 0.74 m2 frontal area
Goal for top 5 cars in 2010 NASC
Anticipated speeds
45-50 mph cruising
85 mph top speed
Odyssey Solidworks Schematics

12. Case Study: Body Design Process
Customer need:
Maximum solar surface area with minimum drag
Problem definition & specifications
Body must fit within a box that’s 1.8m x 1.6m x 5 meters and hold solar array

13. Body Design Continued Data and information collection
Looked at over 30 vehicles from 1989 to now
Consulted books and experts
Evaluation of design and selection of optimal design
Ran computational fluid dynamics on more than 100 separate designs
Tested two best designs by 3D printing at EECS and using wind tunnel in Rogers

14. Body CFD

15. Body Wind Tunnel Testing

16. Implementation of Design
Carbon fiber composite fabrication

17. Making the Car
Phase 1: Making the chassis, suspension, steering, body, wheels
Phase 2: Making the power electronics, attaching motor, batteries
Phase 3: Attach solar cells

18. How You Can Help Help out with design and construction
Attend construction meetings
Meeting times will go out in s, but will typically be Tuesday, Thursday, Friday and Saturdays.
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