Introduction
With the cost of electricity steadily rising, more people are looking for alternative ways to power their homes and electronics. One option is to build your own solar panel using common materials you can easily find. In this guide, I will walk you through the complete process of building a small solar panel capable of charging phones, tablets, and other USB-powered devices for less than $20.
What You Will Need
Building a solar panel requires few supplies, most of which you likely already have or can buy inexpensively. Here is what you will need:
Materials
- Plywood sheet - This will serve as the backing for the solar cells. A piece 12" x 12" is ideal.
- Solar cells - These convert sunlight into electricity. You will need 6 3V/500mA cells.
- Tabbing wire - This thin copper wire electrically connects the cells together.
- Bus wire - A thicker gauge wire that carries current from the cells. You will need red and black.
- Encapsulant - Protects cells from environment. Clear 100% silicone works well.
- Junction box - Houses connections and provides output terminals.
Tools
- Safety gloves & goggles - For handling cells and silicone.
- Soldering iron - To solder tabbing and bus wires to cells.
- Hot glue gun - Secures cells to backing board.
- Multimeter - For testing connections.
- Drill - For mounting junction box to backing board.
Step 1: Layout and Wire Solar Cells
The first step is to mount and wire the individual solar cells together. For this 6 cell panel, arrange them in a 2x3 pattern spaced evenly across the backing board. Put on your safety gloves and goggles before handling cells.
Cut 6 lengths of tabbing wire about 3 inches longer than the cell width. Solder these to the front busbars of the cells using a soldering iron. Be careful not to overheat and crack the cells.
Once tabbing wires are soldered, use a hot glue gun to adhere the cells to the backing board in the 2x3 layout you chose. Leave about a 1⁄4 inch gap between cells to prevent shorts.
2x3 Solar Cell Layout
Step 2: Connect Cells in Series
To increase the output voltage, the cells need to be wired in series. This connects the positive terminal of one cell to the negative of the next.
Cut two 6-inch lengths of black and red bus wire. Solder the red wire to the positive tabbing of the first cell. Connect the black to the negative of the last cell.
Bridge each cell between by soldering the alternating bus wires to the tabbing. Red connects to the negative tabbing, black to positive. Follow the layout diagram below:
Solar Cell Wiring Diagram
Use a multimeter to check the polarity and make sure connections are solid. You should see increasing voltage as you test across each cell.
Step 3: Encapsulate and Weatherproof
The cells and wiring need to be protected from the elements to prevent shorts and corrosion. Put safety gloves and goggles back on and cover the entire panel with a thin layer of clear silicone. Spread evenly across the backing board surface and cells.
Allow the silicone to fully cure for 24 hours. The panel can then be mounted outdoors, but should be angled for optimal sun exposure.
Step 4: Add Junction Box and Wiring
The junction box houses the finishing wiring that provides terminals to connect your devices.
Cut two 8" lengths of bus wire. Feed them through a hole in the junction box, and solder them to the bus wires from the panel:
- Red wire solders to positive bus wire
- Black soldered to negative
Drill two corner holes in the backing board. Mount the junction box using screws or more hot glue.
Install a charging connector or loose wire ends in the junction box output. Use a multimeter to confirm you have the expected voltage - around 18V with a 6 cell panel.
Junction Box Wiring
Using Your DIY Solar Panel
With proper sunlight exposure, your handmade solar panel can deliver enough free, renewable electricity to charge a cell phone, power a tablet, or run small electronics.
To use, simply connect devices you want to charge to the panel's output. Angle the panel towards direct sunlight for maximum power production.
Some tips:
- Track sunlight throughout day
- Ensure full sun exposure and no shading
- Cooler panels operate more efficiently
- Check connections if output falls
Conclusion
Building your own functional solar panel from scratch is entirely possible using common tools and materials. In just an afternoon, you can construct a panel capable of harnessing renewable solar energy to power your USB electronics off-grid for under $20. With a basic understanding of photovoltaic solar energy and following this step-by-step guide, you'll be successfully generating free electricity from the sun in no time!