Solar-Powered Car 1/2024 - 10/2024
Introduction
As part of a 7-person team, my friends and I designed and built a one-seater solar car to compete in the New Energy New Generation 2024 Secondary School Solar Car Competition, organized by the Engineering Dept. of the HK Institute of Vocational Education (IVE) and sponsored by Shell.
We designed and built a single-seat solar car from the ground up, integrating a carbon fiber chassis, a 48V brushless DC motor, and a safety lighting system controlled via a custom mobile app. Our team's focus on innovative safety features earned us the Champion title in the Safety Design Category.
Specifications
🚗 Size & Weight
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Length: 2500 mm
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Width: 1180 mm
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Height: 1300 mm
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Weight (without driver): 98 kg
☀️ Solar & Power
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Solar Panel Area: 0.8 m² / 60W
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Motor: 1000 W (1 kW)
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Battery: 48V LIPO
⚙️ Other Features
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Chassis Material: L-Beam Aluminum Frame
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Body Material: Lightweight Carbon Fiber
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Top Speed (estimated): 25 km/h
Carbon Fibre Chassis
Chassis Material Selection
Our primary innovation is a lightweight, high-strength monocoque chassis constructed from a carbon fiber reinforced polymer (CFRP) sandwich composite . We selected carbon fiber for its exceptional strength-to-weight ratio, with a tensile strength (2500-7000 MPa) far exceeding that of traditional materials like aluminum, steel, or titanium. This choice was critical for maximizing energy efficiency by minimizing vehicle weight without compromising safety or durability. The material's versatility also allowed us to design a aerodynamically efficient monocoque structure that serves as both the chassis and the body
Applying resin to the carbon fibre cloth
Building the cardboard-bamboo structure that supports the carbon fibre layup
Unboxing 20+ meter of carbon fibre cloth
Grinding carbon fiber creates harmful dust, and resin fumes are toxic. I am wearing a respirator and protective suit because safety comes first.
Fabricating Process
Traditional carbon fiber making requires a mold, vacuum sealing, autoclaves and much more expensive equipment, after our research and thinking we ended up using an innovative alternative. By cutting cardboard sizes according to our car size and making a our car model out of cardboard and reinforcing the inside with bamboo sticks, we then covered the part entirely by vacuum bag so the surface is suitable for making carbon fiber. We utilized the wet layup method, saturating carbon fiber cloth over our cardboard-bamboo structure with resin using brushes and squeegees, and then allowed it to dry for hours. We added high density foam board sandwiched between 2 layers of carbon fiber up to 10+ layers thick resulting in a structure able to withstand intense strength.
Dashboard System
The design and implementation of the digital dashboard and control system was a core part of my contribution to the project. I spearheaded the integration of the Arduino microcontroller to centrally manage all vehicle lighting and signals —including left/right turn indicators, hazard lights, headlights, and brake lights — powered by a dedicated 12V lithium battery.
Evolution of the Dashboard Control System
The dashboard interface underwent a significant design iteration to enhance functionality and reliability. The initial prototype featured an LCD touchscreen directly connected to the Arduino. However, this approach presented several critical limitations:
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Pin Depletion: The LCD consumed a majority of the Arduino's available GPIO pins, severely limiting its capacity to control other essential functions, notably the lighting systems.
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Performance Issues: The screen's unresponsive touch interface created a poor user experience.
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Structural Challenges: The direct connection resulted in messy cable management
To resolve these issues, I redesigned to a wireless, smartphone-based dashboard. This new solution utilized an HC-05 Bluetooth module to establish serial communication between the Arduino and a custom mobile application that I designed and coded using MIT App Inventor.
The smartphone app provides a fast, intuitive, and reliable user interface. Moreover, the mobile platform enabled the integration of advanced features like a real-time speedometer utilizing the phone's built-in GPS, greatly exceeding the capabilities of the original LCD screen.
1st prototype using LCD touchscreen Display
Demonstration of mobile app
HC-05 Bluetooth Module
Teaching my friend how to do soldering
Installation in the car
All exposed wire connections and terminals must be insulated with electrical tape or heat-shrink tubing. The carbon fiber monocoque is highly conductive, creating a significant risk of short circuits if any bare wiring contacts the chassis.
More photos
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My sincere thanks to my teammates—Isaac, Kingston, Toby, Benjamin, Daniel, and Alvin—for their dedication, and to our teachers, Mr. Chung, Ms. Tam, and both Mr. Fung, for their invaluable guidance. This achievement would not have been possible without our shared effort and belief in this project.