Wind Powered Electric Vehicle
When we were on a trip sometime back, we were driving with the windows down, I noticed that there was wind pushing in the opposite direction. A few days later, I was reading about electric cars and a few of their drawbacks. One of the drawbacks was the limited driving range. It then struck me that I could harvest the wind around a car while it is moving to charge the car’s batteries.
Different ways to charge electric vehicles have been invented. Things like, conventional charging stations and regenerative braking are a few of those. A conventional charging station takes on an average 30 minutes to a few hours to charge an electric vehicle. This requires the vehicle to be stationary. Moreover, 30 minutes is significantly greater than the amount of time it takes to fill gas in a gasoline vehicle. Regenerative braking seems to have partly solved this problem. However, there is still a lot to be done. Regenerative braking can only produce a limited amount of electricity. And that electricity will be produced only if the brake is applied when the vehicle is moving at a certain speed. Now, when a vehicle is in motion, wind is created around the surface. If the vehicle is moving at a reasonable speed, it would be enough to turn the blades of a small wind turbine. And that is what my idea is based upon.
The vehicle will have multiple small wind turbines connected to the vehicle’s battery. While the vehicle is in motion, the wind created around it will turn the blades, generating electricity which will charge the battery continuously.
That was the facile explanation. This project is based on the Laws of Thermodynamics. The first law of Thermodynamics or the law of conservation of energy, states that:
Energy cannot be created nor destroyed, it can only be transformed from one form to another.
For this project, wind energy is being transformed into electricity to charge the battery.
Now let me elaborate a little bit more. To build the prototype, I used an RC Car. The wind is being harvested by mini-wind generators as shown in the picture on the left. To build the generators, I used four drone motors and four drone blades. Motors are just the opposite of generators. Motors convert electricity into mechanical energy and generators do the exact opposite. Now I had to get the mini-wind generators to turn. To do that, I needed approximately 20 mph of wind. Now I needed a way to measure wind speed. After some internet browsing, I found out that a device called an anemometer is used to measure wind speed. I tried many house hold fans and none of them worked. The average speed generated by them was around 5 mph to 10 mph. I finally found that hair dryers could generate around 20 mph wind, which is the around the minimum wind speed I need. Each mini-wind generator can generate a certain number of volts, which is around 0.8V. To measure the voltage, I used a multi-meter, a device used to measure the various measurements of electricity. To charge the RC Car’s 3.7 volt Li-ion Battery through a USB Cable, I need to generate 5V of stable electricity. To do that, I added four mini-wind generators and connected them in a series configuration. A series configuration is where the voltages add up. To figure that out, I tried numerous different connections. To try the different connections, I used a breadboard. When I connected the mini-wind generators in a series, I was still not able to generate over 0.8V. I then realized that the drone blades were shaped slightly differently. Some spun clockwise and some spun counter clockwise. The clockwise spinning generator was the opposite of the counter clockwise spinning generator. After I took this difference into consideration, I was able to successfully connect the generators in a series.
It would have been close to impossible to keep track of the hundreds of variations I tried if it wasn’t for the breadboard. But I still had a problem. I was only able to generate about 2.1V. I researched on how to boost up voltage and happened to find a DC to DC Boost Converter. When 0.9V-5V and a certain current are inputted, it will output a stable voltage of 5 and a stable current of 600mA. After I incorporated the Boost Converter, I was able to charge the car.
When I was done with building the prototype, I thought about how I could incorporate it in the future on a real electric vehicle.
100’s of mini-wind turbines connected to generate 50V to 100V DC
Converted to ~400V with DC to DC Converter
Continuously charges the Li-ion batteries while the vehicle is in motion
The mini-wind turbines will be aesthetically concealed to not hinder the aerodynamics of the vehicle
Overall, this was a fun project to do. Building the prototype was probably the most intriguing. But it did not stop there. I learnt numerous new concepts, vocabulary, and ideas throughout the process of working on the project.
- Energy cannot be created or destroyed. Energy can be transformed to another energy form
- Different types of windmills
- Different types of air powered vehicles
- How gasoline, hybrid and electric cars/engines work
- Batteries vs Capacitors
- Types of batteries
- Aerodynamics and propeller (blade) types
- Series and parallel configurations
- Voltages add up when connected in series, current adds up when connected in parallel
- How motors/generators work
- How a DC to DC boost converter
- How rechargeable Li-Ion battery RC Car works
- How to measure wind speed, voltage and current
