Homemade Solar Panel Plans

Solar panels can be built in your garage, saving you money.

Though the cost of manufactured solar panels continues to decline, the purchase price can be prohibitive for many people. All the materials you need to build a solar panel are available either at a hardware store or on the Internet. Building and installing solar panels for your home will not only save you money on your electric bill, but the local utility company may end up owing you money every month. Solar panels will also help you to reduce your carbon footprint by reducing greenhouse gas emissions.

Things You'll Need

• 96 solar cells or two 50-cell photovoltaic arrays
• Soldering iron
• Rosin core solder
• Flat wire
• Isopropyl (rubbing) alcohol
• Nylon detail brush
• Small roll of No. 12 gauge insulated wire (red)
• Small roll of No. 12 gauge insulated wire (black)
• 1-by-2-inch wood studs, 8 feet, 4 each
• 4-by-8-foot sheet of 3/8-inch plywood
• Drill
• 3/8-inch drill bit
• 1/16-inch drill bit
• Wood glue
• One dozen 1 1/2-inch wood screws (countersink)
• Two dozen 1-inch wood screws (countersink)
• Two dozen 1-inch wood screws (button-top)
• Silicone sealant
• 4-by-8-foot sheet Plexiglas, 1/8-inch or thicker
• Table saw or circular saw

Instructions

Panel Box Fabrication

1. Square the ends of all 1-by-2-inch wood studs with circular saw or table saw. All studs should be the same length when finished.

2. Cut two 8-foot, 1-by-2-inch wood studs into four 3-foot-10 1/2-inch pieces.

3. Drill eight holes roughly every 5 inches in one of the 3-foot-10 1/2-inch studs using the 3/8-inch drill bit. This will be the center beam in the panel box. The holes are for wiring and ventilation.

4. Assemble the two 8-foot 1-by-2-inch studs and two of the 3-foot-10 1/2-inch pieces into a rectangular shadow box, with the shorter pieces inside the longer ones. Place the predrilled 3-foot-10 1/2-inch piece in the center of the box, parallel with the two end pieces.

5. Drill pilot holes with the 1/16-inch bit. You should be drilling through the side of the 8-foot pieces into the shorter pieces. That will be two holes per end for a total of 12, counting the center stud.

6. Fasten all studs using wood glue and 1 1/2-inch wood screws. Do not fully tighten until all screws have been started.

7. Align the 4-by-8-foot plywood sheet on the frame making sure all edges are flush. Drill two pilot holes on opposing corners and secure with two 1-inch wood screws. Then drill evenly spaced pilot holes around perimeter of plywood 1/2 inch from edge.

8. Remove plywood sheet and clean away any sawdust. Apply a bead of wood glue to one edge of the frame. Secure plywood in place with 1-inch wood screws. Be careful not to overtighten screws; overtightening will cause the wood to warp over time.

9. Remove excess wood glue with a damp rag.

10. Drill two 1/4 -inch holes into plywood for wiring purposes. Holes should be oriented near what will be the bottom of the panel once mounted. This helps prevent leaks when it rains.

11. Seal panel box with a wood sealant such as polyurethane. Applying more than one coat may be necessary to weatherproof the wood. Allow to dry between coats or as directed on package.

12. Align Plexiglas sheet over the top of the box. Hold sheet in place as you drill two pilot holes into it and the studs on opposite corners. Re-drill the pilot holes on Plexiglas only with 3/16-inch drill bit. You don't want to try to thread the Plexiglas with wood screws; the Plexiglas will crack. Secure the Plexiglas in place with two button-top wood screws. Do not overtighten. This will hold the Plexiglas in place as you drill the remaining pilot holes.

13. Drill pilots holes, spaced every 2 to 3 inches, around the perimeter of the enclosure. Remove Plexiglas and clean box of debris. Open up all Plexiglas holes with 3/16-inch drill bit.

Photovoltaic Array Assembly

1. Align solar cells face down on workbench creating two rectangular arrays that will fit inside the two compartments of the solar panel box. Make sure the workbench is free of debris that could damage the solar cells.

2. Apply a small ball of solder to each solar cell terminal by touching the soldering iron to the terminal and then touching the solder to the heated terminal. Do this to all terminals.

3. Solder flat wire across each terminal section in parallel, connecting all cells to each other. The top of the cell is positive and the bottom is negative. Connect positive to positive and negative to negative. Do not connect a cell to itself; this will cause a short and damage the cell.

4. Using the nylon detail brush, clean all solder joints with isopropyl alcohol. Rosin flux in the solder is corrosive and will damage the cell.

5. Solder all positive flat wires together using a short length of No. 12 red insulated wire. Red is positive and black is negative. Solder 3-foot lengths of No. 12 wire, red and black, to their respective terminals. Red wire will connect to the positive (+) terminal run, and the black wire will connect to the negative (-) terminal run.

6. Firmly duct tape all cells together to prevent damage to solder joints as you place the arrays into the panel box. Evenly apply a liberal amount of silicone sealant to the back side of arrays to reduce vibration and keep them in place in the panel box.

7. Place arrays face up in the panel box. Run lead wires through the exit holes, and seal with silicone sealant.

Weatherproofing Panel Box

1. Apply a small bead of sealant on the predrilled frame to fill any gaps in the wood grain.

2. Place the Plexiglas in position, making sure it is oriented correctly before coming into contact with the sealant.

3. Secure the Plexiglas to the panel box using button-head screws. Do not tighten any screws until all screws are in. Do not overtighten screws. Overtightening could crack the Plexiglas and cause warping.

4. Run a bead of silicone sealant around the perimeter of the Plexiglas and panel box. Smooth out the sealant using your finger, making sure there are no gaps.

5. Do not handle panel box for 24 hours as the sealant cures.

Tips & Warnings

• Use light pressure and slow speed to drill Plexiglas. Too much pressure will crack it, and too much speed will melt it.

• Panel box size can be customized to fit the photovoltaic arrays. The assembly method will remain the same.

• Use a multimeter to test the array wiring before sealing the panel box. Panel output should be around 12 volts at 5 amps if wired correctly.

• Some states require a certified electrician to handle any wiring done to the home. Improper wiring may cause personal injury or fires.

References

• Tree Hugger: How to Make DIY Solar Panels with Damaged Solar Cells From Ebay
• Make Solar Panels: How To Make Solar Panels At Home
• Discover Solar Energy: Solar Photovoltaic Panel Projects
• Solatron Technologies: Learn About Wiring Solar Panels and Batteries