Although the price of solar panels has fallen sharply in recent years, they are still too expensive for many people. If you want to gain all the benefits of solar power, whether reducing your carbon footprint or lowering bills, is there another way of doing it?
Can you build your own DIY solar panels and save some money while learning some new skills?
You will be pleased to know that you can. Although it can seem daunting, there is nothing stopping you from buying all the components and creating a solar panel from scratch. As always, if you have little experience working with electricity, we recommend seeking advice from a qualified electrician.
In this guide, we will show you how to:
- Gather the components
- Attach the cells
- Connect the cells
- Construct a box
- Add the protective Plexiglas
- Mount the panel ready for use.
So, the first step is to gather all the components you need. You may have some of these already, while others are easy to find in a local hardware store or online.
Stage 1 – DIY solar panel components
You need a number of components to create your DIY solar panel, including:
- Solar cells
- Tabbing wire
- Bus wire
- Soldering iron
- Flux pen
- Plywood or acrylic sheet
- Wood glue
- Silicone sealant
- Wire cutters/pliers
The most important component, of course, are the solar cells that provide the power for your panels.
Step 1 – The solar cells
Photovoltaic solar cells lie at the heart of the solar panel, and convert energy from sunlight into electricity that you can use and store. There are many types of cell, manufactured in countries including the USA, China, Japan, and Germany.
These cells are very easy to find online, and you may even be able to buy them locally. As always, check the reviews to make sure you are buying reputable components, because skimping on quality to save money can backfire.
While there are various different types of cell, each with their own advantages and disadvantages, the best type for home use are polycrystalline cells. These offer a good cost-to-efficiency ratio and are very durable. You can expect to pay about $1.50 per watt for these cells.
Step 2 – How many cells?
Naturally, you also need to work out how many cells you need. If you are not sure how to calculate how much energy you need from your solar panel, you can check out our useful guide.
When you buy cells, the manufacturer’s specifications will include their capacity, so you can easily work out how many you need. We recommend buying a few extra because accidents are inevitable and you will have some breakages.
Some manufacturers coat cells with protective wax before shipping, so clean this off with hot, not boiling, water.
Step 3 – Testing the cells
Before you start working on your cells, it is a good idea to test them so that you can reject any defective units. Place the cells in sunlight, and on a clean surface with the positive side facing upwards.
With a multimeter, test each cell, looking for a voltage of about 0.5V for a 1.75-watt cell. If you find a value significantly less than this, the cell is probably defective. Check the amps in the same way, for an optimal current of about 3.5 amps.
Stage 2 – Attach the Cells
The next stage involves attaching the cells to a backing board. As a word of advice, you should wear gloves and handle cells carefully because they are very fragile. For extra safety, wear a mask and safety glasses when soldering.
Step 1 – The backing board
To start the process of building a DIY solar panel, fix the cells to a backing board made from a non-conductive material such as plastic, glass, or wood. Wood is a good option because it is easy to drill and cut, but many people choose to use a sheet of acrylic.
Lay your cells out in the chosen configuration before measuring and cutting the board to size, adding about another 2.5cm/1 inch for the bus wires at the end of each row of panels. It is usually easier to lay out the cells in long rows, such as four rows of ten cells.
Step 2 – Cut the tabbing wire
A typical solar cell has two large, parallel wires across the shorter orientation. These wires connect to the tabbing wires and allow electricity to flow through the panel, connecting to the next cell in the array. To make tabbing wires, simply measure the length of these larger lines, double it, and cut.
Step 4 – Flux
Turn the cells over and, on the back of each cell, use a fluxing pen to run two or three lines of flux down the length of each cell strip. This protects the component from the heat of soldering.
Step 5 – Solder
Now, with a soldering iron, melt a thin coat of solder onto the back of the cell strips ready to lay the tabbing wire along them.
You can also buy pre-soldered tabbing, which may be a good option if you are not experienced with a soldering iron, but they are more expensive
Step 6 – Bond the wire
Now, simply heat up the first half of the tabbing wire with the soldering iron, and bond it to the cell. Repeat this for every cell.
Stage 3 – Connecting the cells
With your cells prepared and tabbed, you can now connect them together. When doing this, remember that the top of the cell is negative while the bottom is positive. When connecting, you will connect the positive side of a cell to the negative side of the next.
Step 1 – Glue the cells
Fix the cells to the board with a small dab of strong glue on the back of each, making sure you lay them out in the right direction.
Leave the ends of the two tabbing wires sticking up between the cells, and leave a few centimetres of space at the end of each row for the bus wires. It is important to remember that each row runs in the opposite direction to the previous one.
Step 2 – Solder the cells together
With your flux pen, apply some flux along the thick lines on each cell, known as the contact pads, and solder the free ends of the tabbing wire to these pads. Overall, the two tabbing wires connected to the rear of a cell connect to the front of the next cell along each row.
Step 3 – Add your bus wire
On the first row, solder some tabbing wire to the front of the first cell and make sure the two wires extend a few centimetres beyond the cell into the additional space you left on the backing board.
To create the bus wire, cut a piece of wire to the same length as the distance between the two tabbing wires and solder them together.
Step 3 Connect the second row
Now, you need to connect the end of the first row to the beginning of the second. To do this, use a longer piece of bus wire that covers the two tabbing wires on the first cell and the two tabbing wires on the second. Solder all four wires to the bus wire.
Step 4 – Connect the remaining rows
Use the same process to connect the rest of the rows, and upon reaching the end, connect the two tabbing wires on the final row with a short bus wire.
Stage 4 – Construct the panel box
The next stage involves building a panel box to hold everything in place and protect the unit from the elements. Construct the box from a non-conductive material, such as wood or plastic.
Step 1 – Measure the cell panel
The panel used to hold the cells gives you a base measurement for the size of the box. You now need to make a backing board and the sides of the box.
For the backing board, add about 2.5 cm (1”) on every side to allow some space for the sides of the box. In addition, leave enough free space in the corner for a square piece of wood to hold the protective screen later on.
Step 2 – Cut the box
Cut a sheet of study plywood to the right size and use a piece of 2.5 cm x 5 cm (1 inch x 2 inch) timber to build the sides of the box. Cut two lengths to fit the long sides of your box, and two pieces to fit along the short side. Connect these together using screws and appropriate joints or brackets.
Although the wood does not have to be exactly two inches tall, don’t make it too tall or it will shade some of the panels and reduce efficiency.
Step 3 – Attach the sides
Now, simply lift the constructed frame onto your plywood and screw into place. Use at least three screws per side to make sure it is strong and sturdy.
Step 4 – Paint the box
Paint the finished box any colour you like, and use an exterior waterproof paint for maximum durability.
Step 5 – Attach the solar unit
Now, you can glue your panel into the box, leaving two holes in the end of the panel for the bus wire to pass through, one in line with the first row, and the other in line with the final row.
Step 6 – The diode
Another important step, for safety, is to join the final bus wire to a suitable diode, which is a little larger than the total amperage of the entire panel.
Connect this to the bus wire, making sure that the lighter coloured end of the diode points towards the battery. The diode is a ‘one way valve’ that prevents current from flowing back into the solar panel from the battery.
Step 7 – Connect the wires
Next, connect a wire from the diode to the terminal block, and another from the short bus wire at the end of the first row. Fix the block in place to the outside of the box frame.
Step 8 – Connect to the charge controller and battery
For the next important part of wiring, link wires from the terminal block to the charge controller, making sure that you connect the positive and negative electrodes correctly.
Finally, you can connect the charge controller to the batteries in line with the manufacturer’s guidelines.
Stage 4 – Add the Perspex
With a sturdy box constructed and the wires connected, it is time for the final touch, adding the Perspex cover to the top of the box. This will protect the delicate electronics while allowing sunlight to stream through.
Step 1 – Cut the Plexiglas
Start by cutting the Perspex to size so that it fits the inside of the box snugly. You can use normal glass, but it is difficult to cut to size and more likely to break. Perspex can deteriorate over time, but it is cheap and easy to replace.
Step 2 – Cut and fix blocks
In the corners of the box, where you left some free space, attach some blocks of wood to hold the Plexiglas in place. Cut four blocks from 2.5cm x 2.5cm wood, making sure that they are high enough to hold the Plexiglas above the cells, but below the lip of the box. A drop of wood glue holds them in place securely.
Step 3 – Fix the Plexiglas in place
Now, place the Perspex on top of the blocks and fix into place with appropriate screws, ideally with washers to prevent the plastic cracking. It is always good practice to drill guide holes for screws, and avoid over-tightening.
Step 4 – Sealing
All that remains is to make the box watertight by laying a bead of silicone sealant around the edge of the Perspex. Make sure that the surfaces are clean and dry to ensure the sealant sticks.
Stage 5 – Mounting the panel
Now, the final job is to mount the panel in place, whether in a permanent location, such as on the top of a pole, on a roof, a cart, or a solar generator box.
Wherever you place it, you want the maximum amount of daily sunlight across all seasons of the year, with your completed DIY unit facing the right direction at the optimal angle.
Hopefully, this guide has given you a few ideas on how to make your own DIY solar panels. Whether you want to live off grid, lower your electricity bills, or reduce your carbon footprint, these panels can save you a lot of money and also help you learn some useful new skills.
On its own, a DIY solar panel will not have the capacity for a typical home. At first, it will supplement your power supply and help to lower bills, or you can connect it to a solar generator. Of course, if you enjoyed the project, there is nothing to stop you from adding more at a later date.
Because solar power does not always produce power when you need it, you may want to add batteries to store power and add backup capability. While you can use lead-acid batteries, lithium ion batteries are the best choice because they are efficient, easy to maintain, and cost effective over time.
The solar cells usually last for a couple of decades as long as they are protected from the elements. For the rest of the unit, make sure that everything is painted with good quality paint and that you have applied silicone anywhere water might enter the unit. Don’t forget to check your panel occasionally for wear and tear, and make any repairs.
Building a DIY solar panel requires some electrical knowledge to prevent any risk from electrocution or fires. If you are unsure, we recommend consulting an electrician before and during the project to protect you and your electrical system from harm.
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