Instructables publisher aleutianwind wanted more solar power to take his RV off grid, while still being able to use his lights and small appliances. He had one 120 watt store bought panel, but calculated he would need four more store-bought panels to get the job done.
There was only room for three panels on the roof!
Since roof space was limited, he determined he could build a more efficient DIY solar panel that would produce the same amount of power with only two additional solar panels. Now he has a three panel system that puts out a respectable 9 amps of charging power.
The new system can produce a steady 9 amps.
Here’s how he did it. The project started on eBay, which is where he ordered his 72 solar cells in a kit, along with a flux pen and flat buss wire for making the connections.
He found aluminum frames with glass for the body of the DIY solar panels at a recycling center for $5! Even with the glass, he wanted to fully encapsulate his cells for a longer lasting installation, so he bought encapsulate from eBay as well.
The project started with 72 individual cells.
Each cell was tested before being wired in. The cells themselves are incredibly fragile and most makers say to order a few extra, because it’s not unusual to find them broken in transit.
He measured the power output of each cell individually.
After soldering tabs to a cell, he wired it in a positive to negative series, in rows of 9. Aleutianwind used a straight edge to get neat rows and spaced the cells an even 1/8 inch apart. How many you wire together will depend on the size of your desired DIY solar panel array.
Cells were wired together in series, with 9 cells to a row.
Using flux on each point before soldering will ensure the best bond, so it’s smart to take the time to do this. You don’t want to take these apart later. Test each strip as you go to ensure good, solid connections.
Another test after the cells were wired together – it’s good to catch issues early!
Get some help for flipping these strips over, the cells are incredibly brittle and can shatter with the slightest bump. Aleutianwind recommends cardboard strips under each strip of cells. This cardboard will stay under the fragile solar cells during the entire build, allowing you to move your array easily and safely.
Cardboard strips keep the cells aligned and distribute forces evenly across the surface of the array.
The cells get turned face down, directly on the glass. Make sure the inside of your glass is immaculately clean and dry before applying the cells. It takes 36 cells for each 60 watt DIY solar panel. The strips were then wired together in a series.
Soldering the strips of cells together to form a panel.
A diode gets soldered to one end of the series and a power cord to the other. For this build, he used an old lamp cord.
Here’s the lamp cord visible from the back.
An epoxy encapsulate was then spread over the entire panel, covering the glass and the backs of all cells to completely seal them in. It took three days to dry.
Cells almost ready for encapsulate.
He mentions in his comments that when he has the chance to build more solar panels, he’ll use a roll encapsulate that is much cheaper.
His homemade solar panel in place and wired up.
The back of the panels was them covered with a white plastic bag backing, spread over the epoxy. This part wasn’t necessary, but it provides a nice, clean looking finish.
The full array charging at 13+ volts!
And as for cost, here’s what he had to say,
I have totaled up the project and it came to 208 dollars total or 104 for each 60 watt panel for a total of 1.73 per watt.
The panels have been on our roof for 1 1/2 years, 22 states, over 21,000 miles and show no wear. For a test I switched back and forth between my commercial panel to my homemade and the homemade puts out 1/2 amp more than the store bought. So far we are very happy with the results and will build more when we decide to settle down.