An common way for a DIY beginner to build a solar panel is to assemble individual polycrystalline solar cells into an array. Like a battery, solar cells have positive (back) and negative (front) sides. Though a somewhat tedious process, connecting a small number of solar cells can generate a significant amount of power. For example, an 18-volt solar panel, comprised of 36, one-half-volt solar cells, is capable of charging a common 12-volt battery. Properly assembled and protected, a homemade solar panel can provide years of clean, renewable power.
Things You'll Need
- 1/2 volt polycrystalline solar cells, 3-by-6 inches
- 65-watt soldering Iron
- Tabbing wire
- Bus wire
- Lead-free solder
- Flux pen
- 5/8 inch plywood
- 1 inch wide furring strips
- 1/4 inch acrylic sheet
- silicone caulk
- rubber weatherstripping
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Assemble Solar Cells into a Panel
Run a flux pen over the two main bus lines on the front of a solar cell.
Cut a piece of tabbing wire twice the width of the solar cell. Lay the tabbing wire over a main bus line so half covers the solar cell and the other half hangs off the edge. Repeat on the second bus line.
Run a hot soldering iron over the tabbing wire along the entire length of each front-side bus line.
Flip the solar cell over and place it side-by-side with a second solar cell, back side up. Align the parallel rows of square contact points on both cells.
Wet the six bus contacts on the second solar cell with a flux pen and drip a bead of solder on top of each contact with a hot soldering iron.
Fold the loose sections of tabbing wire from the first solar cell over the contact points on the second cell.
Press the tabbing wire into the solder with a hot soldering iron. When the solder melts, the tabbing wire is attached.
Test if the solar cells are correctly assembled by placing them in full sunlight and connecting a voltmeter to the positive and negative contacts.
Repeat until the desired array size is reached. A compact 4-by-9 cell solar panel is acceptable for a 36-cell array.
Build the Solar Panel Case
Add 2 inches to the length and width measurements of the array dimensions and cut a plywood base to size. Drill a small hole in all four corners of the base for ventilation.
Fasten the furring strips to the sides of the plywood to form a shadow box. Attach rubber weatherstripping along the top of the furring strips.
Center the rows of connected solar cells face-up inside the shadow box. Secure each cell to the plywood with a dab of silicone caulk.
Connect the rows of solar cells in series with bus wire. Leave extra lengths of positive and negative bus wire for connection to a battery.
Cut the acrylic sheet to size and mount over the weatherstripping to create a weather tight seal. Plug any gaps in the box with silicone caulk and protect exposed wood with multiple coats of varnish.