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Solar Wire Size Calculator

For a solar panel system to effectively transfer the converted solar energy to your home, you need to possess the appropriate wiring. It’s not as simple as grabbing some left over copper cable from somewhere in your garage and hooking it up, you need to use a solar wire size calculator to make sure you meet your needs. 

We know this can be daunting at first, but it’s not as difficult as it might seem at first glance. With some basic electrical knowledge, we can quickly figure out exactly what we need.

This article provides you with the information needed to install and manage the wiring of your solar panel system if you're just getting started with your first solar project.

Solar Panel Wiring

A solar panel system is used to absorb sunlight, which is then converted into electricity in order to power your home. The system is made up of various components.

solar panel wire size calculator

The wiring of your solar panel system is a key component to understand when you're setting up your solar array for the first time. This aspect of solar installation is a lot more important and complex than it might seem at first. Wiring that isn't appropriately sized can lead to a drop in efficiency, as well as some serious damage to your system as a whole.

You can have a look at a low-voltage wire gauge chart for what to use between the inverter and your appliances, but you need a different gauge for the wire connecting your inverter to your solar panels.

Before we delve further into the topic of solar panel wiring, let's take a quick detour so that you may understand some key electrical phrases such as voltage, current, and power.

What Is Voltage?

Voltage (V) is characterized as a unit of measurement for the potential amount of electrical energy that can be released in a circuit. A commonly used method for understanding this is the water tank analogy. In this analogy, the water level within the tank is what the voltage would be in an electrical circuit.

The higher the voltage in a circuit is, the more potential the circuit will have, and it will be able to do more.

solar wiring calculator

The voltage levels of a solar array are primarily determined by the size of your solar panel. It can also be swayed by factors such as the amount of sunlight on a given day, shading that may obscure sunlight, and fluctuations in panel efficiency caused by extreme temperatures.

What Is Current?

Current (I) refers to the rate that the electrical charge flows within a circuit. The unit of measurement used for electrical current is amperes (amps). Using the water tank analogy, electrical current would be the water flowing through the pipe.

Because the current of a system is related to its resistance, you need to use a battery cable ampacity chart to make sure it’s running efficiently.

What Is Power?

Power (P) is what you get when you multiply the voltage by current, in other words: 

P = V x I 

It’s characterized as the rate at which energy is transferred through a circuit. The unit of measurement for power is watts (W) and kilowatts (kW).

Power is regulated by the inverter, which maximizes the energy output of the solar panel system. When explained through the use of the water tank analogy, power would represent the rate at which the water flows through the pipe.

Solar Panel Wire Size Calculator

To calculate the wire size your solar panel system needs, you have to learn some of your system's electrical specifications.

solar cable size calculator

You first need to learn how much your solar system’s working voltage is. If your system is connected to a battery bank then you'll need to know what its voltage is. This is to know the working voltage levels across the wire connecting to the load.

A good wire gauge voltage chart will prove invaluable for this.

You’ll then want to learn what your solar array's expected peak working power is. This should be measured in either watts or kilowatts.

You also need to know what your cable’s working temperature is, in either Celsius or Fahrenheit. This is important because the higher the working temperature of a cable is, the higher the wires’ resistance will be. This can cause the voltage to drop and will lessen the amount of electrical current the wire can sustain.

Resistive loss can be influenced by wire length and diameter as well. Continuing the topic of resistance, your desired resistive loss the cable will have in percentage needs to be known as well.

You then add the length of wires you plan on going with, in feet (ft), and then use all the information you gathered to calculate whether or not your supposed cable length would be suitable. There are various calculators available online that are used to calculate wire size using this information.

Solar Panel Wire Gauge Calculator

How Solar Panel Wiring Works

For a solar panel system to function efficiently, all the components need to be connected via wiring. This wiring makes up the circuit through which the electrical current of your solar array will flow.

solar wire gauge calculator

You'll want to keep in mind that the voltage output level and size of your wiring will need to be compatible with that of your inverter. An inverter will have both a maximum and a minimum voltage output level, and your system's voltage levels will need to fall between the two to function efficiently.

Failure to do so may result in a drop in efficiency or even damage to the inverter itself. This is why it is important to calculate wire size beforehand.

Before you can get your solar system up and running, you need to consult a battery cable sizing chart to make sure you have the right equipment to hook everything up.

There are two different ways to go about stringing your solar panel system, for both the panels and the inverter. Each of them will have different effects on power production. The different configurations are known as series and parallel.

Connecting Your Solar Panels In Series

Solar panels are similar to batteries due to them also having positive and negative terminals. Connecting solar panels in series means connecting the positive terminal of one panel to the negative terminal of its neighbor.

When a solar array is arranged in series, the voltage of the panels will be added together. The amperage, however, will remain the same. Connecting the solar panels in this manner can increase the voltage and helps the array reach certain voltage requirements that it might not have been able to before.

Connecting Your Solar Panels In Parallel

When you connect a solar panel array in parallel, you are connecting the positive terminal to the positive on the neighboring panel, and the negative to the negative.

Connecting your solar panels in parallel will increase the amperage while the voltage stays the same. This configuration will allow more of your solar panels to produce energy without exceeding the maximum voltage limits of your inverter.

If your system has a higher-than-average voltage, have a look at our high-voltage cable size chart so that everything can be safe and have a long lifespan.

Solar wire size chart

Wiring your solar panels in parallel can also allow you to meet the minimum amperage requirements set by your inverter.

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