The West Philadelphia High School Electric Vehicle Team
| |
The West Philadelphia High School Electric Vehicle Team |
The Electric Saturn
Saturn of Trevose donated a 1993 SL2 for our electric vehicle team. Our team spent hundreds of hours researching available technologies, designing conversion plans, approaching sponsors for support, and applying all we learned to convert this vehicle to a race worthy electric powered automobile.
The Drive System
MTS Systems Corporation Automation Division donated a 324 volt brushless D.C. electric motor and a 100 amp drive (amplifier). The system is rated at 35.7 HP continuous and has a maximum of 3000 RPMs. The Saturn had a top speed of about 67 mph. The reason we chose this motor is that it is the most efficient on the market. Efficiency (the amount of energy the motor wastes) is the most important characteristic for the Tour de Sol race. This drive system not only proved to be the most efficient, but it was also incredibly durable. MTS truly gave us a competitive edge!
The Batteries
Although battery technology is advancing rapidly, unless you have a sugar daddy, advanced batteries are still not readily available. Therefore we searched for the best deep-cycle lead acid battery on the market. We defined "best" by the highest energy density. Energy density is the amount of energy (watt-hours) per kilogram of weight of the battery. East Penn Manufacturing donated 30 Deka DC27 batteries which have an energy density of 38 Wh/kg. We use 27 to power the vehicle and 1 to for the 12 volt systems on the car. The extra two are back-ups for the race. This pack will provide about 25 kilowatt - hours of energy and weighs in at 1450lbs. We have calculated that this pack should take our vehicle about 150 miles at 50 mph.
The Tires
Michelin donated a set of their low rolling resistance tires which were designed for GM's EV1. The Proxima RR has the lowest rolling resistance of any tire on the market. We are using a 205/60 R 15 tire which is inflated to 51psi. The low rolling resistance should greatly increase the vehicles range. We placed the tires on the lightest weight rims we could find. Dazz motor sports provided forged aluminum rims that weigh in at 7.7 lbs each and were sold to us at cost (only $270 each).
The Suspension:
Sprint Springs donated four heavy duty racing springs and a really cool strut tower bar. We purchased KYB shocks, and replaced the sway bar bushings. We also fabricated our own rear strut tower bar and welded it in the trunk. It should greatly increase the rear suspension rigidity.
