Solar Panel Terminals

So, you just got a solar panel that has no polarity labels. How can you figure out the proper polarity, which terminal or wire is plus and which is minus? Here’s a couple of easy tips than can even be done inside, away from the sun.
If you can open up the junction box, you will likely see at least one bypass diode inside. This is to help prevent power loss due to shading of a Diagram of the flow of electricity in a solar panel system .
It provides an alternative path for the current when the panel is shaded, and therefore at a higher resistance. There may only be one diode, which bypasses the whole panel in a solar array, as seen in the diagram, or multiple diodes, bypassing cells within the solar panel itself.