How to Make 300 Watt Solar Panels

Even an energy efficient solar home with an absolute minimum electrical demand will require a lot of power. Many people are surprised by the sheer number of panels needed to generate enough electricity to power a home, but they should not be. The image of a roof filled with solar panels is not unfamiliar these days. Getting the best power output while making the best use of available space might mean building your own, custom-designed 300 watt panel.

Things You'll Need

• At least 36 mono-crystal solar cells
• Paper
• Pen
• 3/8 inch thick plywood
• Sawhorses
• Hand saw
• Hammer
• Nails
• Scrap lumber
• Drill
• Corkboard/Masonite peg board
• Primer
• Paint
• Brush
• Wood glue
• Screws
• Washers
• Screwdriver
• Soldering gun
• Silicon caulk
• Copper electrical wiring
• Wire nuts
• Standard electrical plug
• Plexiglass cutting tool
• Plexiglass plate

Instructions

1. Go shopping on the Internet for the solar cells or minipanels. You will need to assemble enough individual units to provide your target of 300 watts.

2. Start designing your panel. The panel itself is just a box into which your individual cells or minipanels are going to be assembled. For example, this project will use 30 10-watt cells that are 15 inches by 9 inches. The cells will be arranged in six rows of five each, with a padding of one inch between everything and around the border. That means we need to design a panel with a backing of 96 inches wide and 61 inches long. This should be sketched out with each individual solar cell.

3. Place a 3/8 inch plywood sheet on sawhorses, and cut it to match your specifications with a hand saw.

4. Saw scrap lumber into four borders for the panel. then nail them into a box around the sides of the plywood. The border should be raised from the surface of the plywood by at least 1 1/2 inches. Heavy molding can be used as a substitute if the scrap lumber is unavailable.

5. Drill several small holes around the sides of your borders. These holes will serve as vents.

6. Saw or cut a piece or pieces of corkboard or Masonite peg board to fit the inside of the panel. Any nonconductive material can be a substrate in this role, so be imaginative with your scrap materials. Fasten this with glue, plus screws and washers in the corners, where there won't be any contact with the solar cells or wiring.

7. Prime and paint the box with a brush. The solar cells will be warrantied to last between 20 and 25 years, so you should protect the panel itself with a couple of thick coats of paint.

8. Take a marker and draw guidelines for the placement of your individual cells.

9. Take a group of cells, turn them over, and solder them together. Solar cells usually come with tabs meant for this purpose, so this should be easy. Soldering them into groups makes the cells easier to handle and offers support within the panel. In this example, they could be soldered by either rows of five or columns of six.

10. Place one or two silver-dollar sized dabs of silicon caulking in the center of each cell from one of the groups, and then fix each set of cells into its assigned location on the panel. Repeat until all groups are placed.

11. Use electrical wiring cut into small pieces to join the cells. Each cell will have a pair wires coming out of it. Identify the positive and negative from the cells, match them to the positive and negative leads of your wiring, and splice them together using wire nuts. This will make the wires long enough to be bridged. Exactly how long will depend on the design, but in this example roughly one foot sections of wire are required for each of the 30 cells.

12. Start bridging the cells together by splicing them with wire nuts. In this example, we could run the wiring from three cells and splice them with wire nuts to a new wire. Doing this reduces the number of wires to 10, which can be further bridged until only one wire remains. The wiring from all of these bridgings is going to become a confusing tangle, so they should be glued to the panel floor to fasten them down in a neat, organized fashion as you go.

13. Drill a hole through the back of the panel, near the bottom, to run the unified, single wire out of the panel. Use silicon caulk to seal the hole.

14. Install the positive and negative exterior leads to a standard utility plug. This will involve wrapping the positive and negative leads of the wiring around screw connectors and tightening the screws.

15. Use a Plexiglass cutting to cut a sheet of Plexiglass to fit over-top the panel. Drill matching holes through the Plexiglass and panel borders, and screw the Plexiglass to the exterior front of the panel.

16. Connect the exterior wire to either a battery charge controller or to an inverter. Once the panel is exposed to full sunlight, it will generate at the rate of 300 watts within seconds.

References

• Homemade Solar Panels
• Build a Solar Panel