When you connect the cells in parallel, the current or amperage is multiplied and the voltage is maintained at the same level as before. Due to low voltage and high current, this method is not recommended, as you will lose power in proportion to the ratio of current squared to resistance. They’re easy to make and a lot of fun. The solar cells are connected to one another by soldering a tin-coated flat wire to tinned strips on either side of the cells. The voltage and amperage you get will depend on how you connect them. It costs $18.60 to build a 12-volt 9-watt solar panel, whereas a 12-volt 90-watt solar panel costs $373.50, including backboard and flex glass in addition to the usual costs.

Allow the solar cells to reach at least 100 degrees Fahrenheit before attempting to attach the soldering iron’s lead wires to them. A hot soldering iron could cause the cells to break if you touch them when cold. 374 degrees Fahrenheit is the melting point of excellent rosin core solder.

In order to make sure that each cell is properly connected to the next, use a voltage meter to check each connection. Tinned wires should not be left hanging over the edge of solar cells, since this will short out the cell and prevent it from generating any power for your solar panel.

To prevent solder from flowing onto the terminal below, either cut the tinned wire back so that it cannot touch the other tinned wire or use solder wick, which is a spool of small strands of copper wire. Snip off a little piece and set it on top of the hot-soldered joint; this will help remove any extra flux.

To power your device, attach the first and last solar cells to two terminals on the edge of the rear board, and link these terminals to your device. Verify the solar panel’s voltage and polarity with a voltmeter and mark the + plus and – minus terminals accordingly.

The output voltage will be determined by the amount of solar cells you connect in series. Connect the output leads to any device you wish to power. Using different sized solar cells, you may generate any desired output voltage and current in steps of 0.5 volts DC.

If you want to keep the voltage the same, you can connect the cells in parallel, where the current or amperage is added together. This is a bad idea because the voltage is too low and the current is too great, resulting in a loss of power proportional to the square of the current times the resistance.

With 28 solar cells, you may build a 12 volt DC solar panel. All of these solar cells output between 0.5 and 0.55 volts of voltage. A DC voltage of 14.4–15.4 volts is generated by 28 cells connected in series. To properly charge a 12-volt battery, you’ll need at least two more volts.