How To Build A Solar Panel

Step 8 Installing the Junction Box

Next, in Part 11 of the video, I finished connecting my back pieces of plywood that was going to support my whole solar panel when I was ready to mount the panel on my roof. I also installed a junction box onto the back of the solar panel since most solar panels include a junction box. As seen in the video, my junction box came with a blocking diode which prevents the backflow of current when you have the solar panel hooked up to a battery. Most charge controllers prevent the backflow of current already, but if the charge controller does not, you will need to install a blocking diode onto the solar panel. It is best to install the blocking diode on the outside of the panel just in case something was to ever happen to it so you can easily replace it.

Lastly, I took my silicon and went around all my edges of the solar panel, as well as the junction box on the back. Next I made a final voltage/current check and was ready to mount the panel to my roof.