A solar panel wiring diagram (also known as a solar panel schematic) is a technical sketch detailing what equipment you need for a solar system as well as how everything should connect together. There’s no such thing as a single correct diagram — several wiring configurations can produce the same result.
The diagram below shows the working principle of the most basic solar charge and discharge controller. The system consists of a PV module, battery, controller circuit, and load. Switch 1 and Switch 2 are the charging switch and the discharging switch, respectively.
There are several ways to create your own solar panel wiring diagram — you can draw it out on paper, print out an existing diagram and mock it up with a pen to fit your liking, or design it from scratch digitally.
The simplest possible solar battery charging circuit is just to connect the positive wire from a solar panel to the positive battery terminal, and the negative solar panel wire to the negative battery terminal. This was the main practice back in the day, and will quite happily charge a battery! However, there are two potential problems:
12V is the most common solar panel wiring connection with batteries, as most appliances are designed to operate on 12V. With a 12V system, parallel orientation is usually preferred for both panels and batteries. This is because increasing the amps allows for devices to be powered for much longer than they could be when wired in series.
Solar panels and batteries can each be wired in one of two orientations: series or parallel. These orientations determine whether your devices’ amperage or voltage increases — an important consideration depending on what type of controller and batteries you’re using.