DIY Solar-Powered Emergency USB Charger for Camping and Hiking

Welcome to this DIY guide where we will build a portable solar-powered USB charger. This project is perfect for outdoor enthusiasts, electronics hobbyists, and anyone interested in renewable energy. With a few simple components, you can create a reliable and eco-friendly power source for your USB devices.

Why Build a Solar-Powered USB Charger?

Building a solar-powered USB charger allows you to harness the power of the sun to charge your devices anywhere. It's a great way to learn about solar energy, practice your electronics skills, and create a useful tool that can keep your devices charged during outdoor activities or emergency situations. Plus, it's an environmentally friendly alternative to traditional chargers.

Project Features

• Solar-Powered: Utilizes solar panels to convert sunlight into electrical energy.
• Portable: Compact design makes it easy to carry and use anywhere.
• USB Outputs: Provides both USB Type-A and Type-C ports for versatile charging options.
• Battery Storage: Includes a battery pack to store energy for later use.
• Real-Time Monitoring: Equipped with a wattmeter to display real-time voltage and current readings.

Safety First

Before we begin, it's crucial to prioritize safety. Working with electrical components and solar panels involves risks such as electric shocks and short circuits. Always work in a well-ventilated area, use protective gear, and double-check connections before powering up the device.

Disclaimer

Please note that this project involves working with electrical components and solar panels, which can be dangerous if not handled properly. Ensure you follow all safety precautions and double-check your work. I am not responsible for any damage, injury, or loss that may occur as a result of following this guide. Proceed at your own risk and always prioritize safety.

Materials List

Below is a list of parts needed, including quantities and links for purchase.

• 3D Printable Frame - 1 set (Custom designed to house the components)
• Battery Holder - 1x - Holds two 18650 batteries.
• Battery Level Indicator 1x - Displays current charge level of the batteries.
• Solar Panels - 6x - Mini solar panels rated for 5.5V 60mA.
• Dual USB Socket - 1x - Provides both USB Type-A and Type-C ports.
• Wattmeter - 1x - Digital LCD Display to monitor voltage and current.
• Charge/Discharge Controller - 1x - Manages charging and discharging of the battery.
• DC-DC Buck Converter - 1x - Used to upscale the voltage from the solar panels.
• Voltage Regulator (7805) - 1x - Ensures a stable 5V output from the solar panels.
• Capacitors - 2x - 0.1µF and 0.33µF for the voltage regulator circuit.
• Dupont Connectors - 1 set - For connecting wires easily.
• XXL Waterproof Rugged Box 1x - For housing the components.
• Any 18650 Batteries (I strongly recommend getting some more expensive ones and not cheap ones from China. They should be rated for up to 80 degrees celcius operating temperature) - 2x

Tools Required

You will also need the following tools to assemble and complete the solar-powered USB charger:

• Soldering Iron: For making secure electrical connections.
• Wire Strippers: Essential for preparing wires - I recommend this one
• Screwdrivers: Needed for assembling and disassembling the components.
• Multimeter: For testing voltages and ensuring connections are correct.
• Pliers: Useful for bending wires and handling small components.
• Crimping Tool: For crimping Dupont connectors - I recommend this one
• 3D Printer: For printing the custom frame.

Before starting the assembly, begin by 3D printing the frame to house and support the components of your solar-powered USB charger. This will allow you to work on the electronics while your 3D printer creates the necessary parts.

Print Settings

For the main parts, use a 0.4mm nozzle diameter, which provides a good balance between print speed and detail. Set the layer height to 0.2mm; although 0.3mm is viable, it tends to give a less finished appearance. Use 15% infill in a Grid pattern for good strength without excessive material usage. The recommended material is PETG due to its heat resistance, making it ideal for parts that might be exposed to sunlight.

Ensure your print bed is clean and properly leveled to avoid adhesion issues, especially since PETG can warp. Adjust your print speed and temperature according to your specific printer’s capabilities and the manufacturer's recommendations for the PETG filament.

Mount and Glue the Solar Panels: Begin by mounting all the solar panels onto the designated housing. Ensure that they are securely attached and positioned to receive maximum sunlight exposure. Use adhesive to fix them in place.

Solder the Connections: Once the panels are securely mounted, carefully solder all the negative terminals of the solar panels together to form a common ground. Repeat the process for the positive terminals. This parallel configuration will help maintain a stable voltage while increasing the current output.

Create and Mount the Voltage Regulator: Next, create a small voltage regulator to ensure that the power supplied to the charge controller is stable. Solder the components onto a perfboard and secure the regulator onto the housing near the solar panel connections.

Assembling the Watt Meter

Start by removing the housing of the watt meter. This allows it to fit seamlessly into the 3D printed frame.

Place the watt meter into the designated slot in the frame, ensuring it's securely positioned.

Desolder the original thick wires and replace them with thinner wires for ease of connection.

Connect the Solar Matrix

Thread the black and red wires coming from the solar panel matrix through the holes on both plates as shown in the picture.

Connect the wires from the solar panel matrix to a DC buck booster and then to the input (IN) of the watt meter.

Crimp Dupont connectors onto the wires coming from the output of the DC buck booster.

Installing the Charge Controller

Get the solar charge controller and connect the output of the watt meter. Solder the black wire to the corresponding GND and the red wire to VIN on the charge controller.

Position the lithium battery holder into its slot and solder the red wire from the battery holder to the BAT terminal and the black wire to the GND terminal on the charge controller.

Solder the red and black wires from the Battery Level Indicator into the same BAT and GND as the battery pack.

Clip the USB charging ports into the panel and solder the red wire from it to the OUT 5V terminal and the black wire to the GND terminal on the charge controller.

Final Assembly

Press the charge controller into its slot. Connect the two Dupont connectors to the COM terminals on the watt meter. Insert the batteries into the battery holder.

Place both panels into the waterproof box, completing the project.

Last Thoughts

Congratulations on completing your DIY solar-powered USB charger! This project not only enhances your understanding of solar power and electronics but also provides a practical tool for charging your devices on the go.

Share Your Build

We'd love to see your version of this solar-powered USB charger! Share your build and any modifications you made in the comments.

Thank you for following this guide. Happy making!