# Solar Car FAQs

What is it?/Is that a boat?
It is a solar car that runs 100% off of power generated from solar energy. And no, it’s not a boat.

What does Gato del Sol mean?
Gato del Sol is the 1982 Kentucky Derby winning thoroughbred and the namesake for our car. Stone Farm, who raised Gato del Sol, has been a longtime supporter of the University of Kentucky Solar Car Team. Gato, meaning “cat” in Spanish, and Sol, meaning “sun” in Spanish, is a very fitting name for Wildcats racing on the power of solar energy.

How does the car work?
The power comes in from the solar cells and is sent through a wire to the motor. When we drive, we try to operate the car with just this energy. If the solar cells cannot provide enough power (accelerating, fast driving), then we have to get the extra energy from our batteries. If we don’t need all of the power the solar cells are producing (braking, sitting at a stoplight), then we charge the batteries. This is all controlled by the car’s on-board computers, so the driver can focus on driving.

How does solar power work?
A solar cell produces power by converting sunlight into electricity. When sunlight, which is composed of photons, strikes a solar cell, the photons are either reflected or absorbed. The absorbed photons’ energy is transferred to an electron which is contained inside the solar cell. With the new energy, the electron is able to “escape” its original position and become part of the current produced by the solar cell.

Why don’t you put a small person in the car to save weight and make the car more efficient?
The rules say that every driver has to weigh 176 lbs. If he/she is under that weight, ballast must be added so that every driver from every team weighs the same.

Why don’t you use wind turbines to generate electricity while you are driving?
This simply violates the law of conservation of energy. So, say we attach wind turbines to our car and use 20 watts of energy due to the drag of the turbine. The maximum amount of energy that we could get back would be 20 watts which would make the turbine 100% efficient. So, even with a turbine with an efficiency of 100% (no mechanical device has been created with this high of an efficiency), the amount of energy that we get back would not be larger than what we used.

Why are the shocks horizontal?
The horizontal shocks increase the handling and make it easier for the chassis to absorb the loads delivered from the surface of the road, similar to Indy-style cars.

What is that popping sound when the car moves?
Brushless motors move because of pulses that the motor controller sends to it. Those pulses produce the AWESOME popping sound that will eventually progress into a hum as the car speeds up.

Why does it have three wheels and is it safe?
This configuration is more efficient than four wheels because you have less aerodynamic drag and rolling resistance by ditching one wheel. It is also much easier to design and build. As for its safety, yes, it is safe. If a three wheel car is designed correctly, it can handle well enough to deal with what you would encounter on the roadways. Our drivers say it handles as well as, if not better, than many gas-powered cars on the road.

Does it have air conditioning?
No. Air conditioning wastes a lot of energy and has no place in our vehicle. Instead, we have well-placed vents that keep the driver cool when moving. If needed, we can add fans to cool the driver when stopped.

How many people work on it?
There are currently around 20 active members. Before a car’s completion, more than 50 University of Kentucky students will contribute to the production.

When will we see a car like this for the everyday consumer?
It will likely be a very long time. Though the sun’s energy makes life on Earth possible, it is not strong enough to power a car as we think of them nowadays. The general number for power density of sunlight is 1000W/m^2. If it were possible to harness all of that power, a typical sedan would have to run off 10-20 hp. This is far less than the consumer cars on the market.
But don’t let that discourage you. Much of the technology and initiatives pushed by Solar Car Racing are beginning to be used in consumer cars. The new Toyota Prius includes a solar roof to power some of the auxiliary parts. All hybrid cars make use of regenerative braking. In solar car racing, we strive for high efficiency wherever possible. In a consumer car, this equates to highly increased MPG (for an ICE car) or M/kWH (for an EV car).