Solar Panel Wiring For 12v System

You need to understand how different stringing configurations impact the voltage current and power of a solar array.

Solar panel wiring for 12v system.

Wiring solar panels in parallel causes the amperage to increase but the voltage remains the same. The following solar panel wiring diagram shows that a 12v 120w pv panel is connected to the solar charge controller panel negative terminal of panel to the negative terminal of mppt charge controller and vice versa for positive terminal. This is much too high for lead acid batteries and will cause excessive grid corrosion and pressure venting and rapid failure of the battery. With parallel solar panels the positive terminal from one panel is connected to the positive terminal of another panel and the negative terminals of the two panels are connected together.

A solar panel will continue to charge to its open circuit voltage which is usually around 17v for panels used in 12v systems. Usually the solar power systems use 12 volt batteries however solar panels can deliver far more voltage than is required to charge the batteries. Enter solar panel output voltage. Enter the total amps that your solar panels will produce all together.

Enter the distance in feet from your solar panels to your battery bank charge controller. Generally to achieve the 12vdc to 120 230vac system both pv panels and batteries are connected in parallel. By in essence converting the excess voltage into amps the charge voltage can be kept at an optimal level while the time required to fully charge the batteries is reduced. Volts with two solar panels and two batteries wired in parallel your volts remain the same at 18 volts panels and 12 volts battery bank so you will only be able to charge a 12 volt battery bank and thus power up to 12 volt appliances.

Solar panel wiring aka stringing and how to string solar panels together is a fundamental topic for any solar installer. A great way to go about choosing the wire thickness for your solar system is to buy solar panel wire big enough to cope with the biggest current amp drawing appliance you have and using that wire for all the other runs to the ac breaker panel. Off grid systems have a bit more flexibility and solar owners will sometimes connect their panels in parallel to meet their battery needs 12 volt solar system to charge a 12 volt battery for example. Use a wire sizing calculator for solar arrays that will figure out the size of wire you need.