How to Build a Low Cost DIY Solar Panel to Save Money on Your Electric Bill

Introduction

With electricity rates constantly rising, installing DIY solar panels can be a great way to save money on your electric bill in the long run. DIY solar panels are affordable, easy to build with common tools, and can provide free electricity from the sun once installed. In this comprehensive guide, I will walk through all the steps necessary and considerations needed to successfully build your own low cost DIY solar panel system.

Gather the Necessary Materials and Tools

The first step is acquiring all the necessary materials and tools to build the DIY solar panels. Here is what you will need:

Materials

• Solar cells - These are the main components that convert sunlight into electricity. You can purchase affordable 3" x 6" polycrystalline or monocrystalline solar cells. You will need around 36 cells for a 100W system.
• Plywood or MDF board - This will serve as the backing board and enclosure for the solar cells. Get a 4' x 8' sheet for adequate room.
• Plexiglass - A transparent protective layer that goes over the solar cells. Acrylic plexiglass sheets are inexpensive and easy to work with.
• Silicone caulk - Used to waterproof the panel enclosure and adhere the plexiglass and cells. Make sure it is 100% silicone.
• MC4 solar panel connectors - Special connectors to wire the panels together. You will need a male and female connector.
• Copper wire - For interconnecting the solar cells and connecting to the charge controller. 12 AWG copper wire works well.
• Soldering iron, solder, and flux - For soldering the solar cell tabbing wires together.

Tools

• Safety gloves and goggles
• Pencil and ruler - For marking the layout on the backing board.
• Hand saw or power saw - For cutting the plywood or MDF board to size.
• Electric drill - For drilling holes to mount the MC4 connectors.
• Screwdriver - For securing the plexiglass and mounting the connectors.
• Wire cutters and strippers - For cutting and connecting the copper wire.

Plan the Panel Size and Layout

Once you have all the components, the next step is planning the overall size of the panel and laying out where all the solar cells will go.

Some guidelines when planning:

• The plywood backing board should be about 1-2 inches wider than the solar cell array on each side. This allows room for mounting and sealing the edges.
• Allow about 1/4" spacing in between each solar cell for room to run the tabbing wires.
• Draw a grid on the backing board to map out the solar cell positions and sequence of connections.
• Having the cells arranged in series strings of around 5-8 cells works well for 12V and 24V systems.

Here is an example layout diagram for a 36 cell panel with 6 cells in series:

Make sure to refer to your planned diagram frequently as you wire up the panel.

Mount the Solar Cells

With your layout complete, it's time to mount the solar cells to the backing board.

Follow these steps:

• Put on your safety gloves and goggles.
• Apply a generous bead of silicone caulk to the back of each solar cell, keeping it around the edges.
• Position the cells on the backing board one by one following your layout diagram.
• Gently press down on each cell to secure it in place in the silicone caulk.
• Use clamps or weights to keep even pressure on the cells while the silicone sets. The caulk will need about 24 hours to fully cure.

The silicone caulk will provide adhesion as well as waterproofing for the panel backing.

Wire the Solar Cells in Series

Wiring the solar cells together in series is a crucial step to build the proper voltage and power output.

Follow these basic steps:

• Lay down a bead of silicone between each cell with gaps for soldering the wires.
• Solder a tabbing wire between the negative terminal of one cell to the positive terminal of the next cell.
• Repeat to connect all cells in series strings according to your layout.
• Carefully insulate each solder joint with silicone caulk.
• Let the silicone fully cure before moving the panel.

Refer frequently to your diagram while wiring and double check the polarity of each connection.

Weatherproof and Enclose the Panel

Now that the cells are wired up, you need to seal up the panel to protect it from the elements:

• Run a bead of clear silicone around the edges of the backing board to seal it.
• Once cured, adhere a sheet of plexiglass over the top, leaving a small gap on one side.
• Seal around the edges of the plexiglass thoroughly with silicone.
• Allow at least 24 hours for the silicone to fully cure before using the panel.

The plexiglass provides a transparent protective barrier while silicone caulk weatherproofs the panel.

Connect the Wiring and MC4 Connectors

To complete the electrical connections:

• Solder the positive and negative wires from the panel wiring to the male and female MC4 connectors.
• Mount the MC4 connectors in a cutout on the plexiglass side using silicone and screws.
• Drill holes for feeding the wires out and seal with silicone.
• Run the wires out and leave about 12" excess to connect to the charge controller.
• Apply some UV resistant tape around the wires for protection.

With the MC4 connectors installed, you will be able to easily connect your DIY solar panel to other panels or a charge controller.

Mount the Panel and Connect to a Charge Controller

For installation:

• Use aluminum brackets to securely mount your DIY solar panel in a sunny location.
• Point the panel towards true South if in the Northern hemisphere or true North in the Southern hemisphere.
• Tilt the panel at an angle equal to your latitude for maximum year-round production.
• Connect the MC4 leads from the solar panel to your charge controller maintaining proper polarity.
• Follow the charge controller instructions to connect your batteries and inverter as needed.

With proper mounting and connections, your DIY solar panel will provide free power for years to come!

Maintaining and Troubleshooting Your Solar Panel

To keep your solar panel performing optimally:

• Check that all wiring connections are intact and free of corrosion. Tighten or resolder any loose connections.
• Check for any damage to the solar cells or cracked silicone. Immediately fix any leaks or cracks that could let in moisture.
• Wipe off any accumulated dirt or dust from the plexiglass surface which can reduce output.
• Verify your charge controller is working properly and that power is going to your batteries.
• If output seems low, check the orientation and clean off any shade obstructions.

Following these maintenance tips will extend the life of your DIY solar panel and keep it performing optimally.

Conclusion

Installing your own affordable DIY solar panel to generate electricity can be very rewarding. Follow the steps outlined here to successfully build a low cost solar panel using common tools and materials. With some patience and attention to detail, you can create a fully functional solar panel that will provide free clean electricity for your home for years. Utilize this guide as a reference for planning the layout, wiring the connections, weatherproofing, and mounting your finished panel. Going solar with DIY panels is a great way to save substantially on your electric bill.