HOW TO WIRE SOLAR PANELS

With the increasing need to conserve energy, it’s become easy to embrace more natural and eco-friendly ways of generating power, leading to the rapid growth in the solar energy industry. Solar panels and systems are quickly becoming more accessible for consumers, allowing homeowners to utilize them to power their homes.

However, one of the most important factors when installing a solar panel system is to ensure that it’s wired correctly, based on your needs. The main difference between wiring solar panels in Series vs. Parallel is that the voltage and amperage of the circuit will be affected. The energy production capacity of a solar panel is measured in watts, which can be achieved by multiplying the amps and its voltage. It is critical to find an appropriate balance of amps and voltage for the system to perform well, therefore providing a better return on investment.

In this article, you will learn how to install your desired connection, why certain types of wiring are utilized, and which type is most beneficial for you.

Types of Solar Wiring

There are essentially three types of solar wiring: Series, Parallel, or a combination of Series and Parallel wiring.

1. Wiring Solar Panels in Series

Series wiring is used to specifically increase the voltage of the total solar panel system. The current travels along only one path, which means that the circuit current must pass through all loads. Since the Series circuit flows in a single line, any damage to one string point will affect the entire circuit.

For example, most older Christmas lights are wired in a Series circuit. If one bulb is affected, the rest of the string lights will go off. Fortunately, modern Christmas lights use Parallel wiring, eliminating the issue altogether.

The Series wiring is typically used when charging a controller that needs more than 24 volts or an inverter that’s connected to electrical grid.

Steps for Connecting Solar Panels in Series

The Series circuit is achieved by connecting the positive (+) terminal to the negative (-) one for each panel.

This will then leave you with one available negative (-) terminal and one available positive (+) terminal, that will be connected to the charge controller or inverter.

1. Wiring Solar Panels with Similar Characteristics in Series

In this scenario, the solar panels will be similar in power rating and type. The individual voltage from each panel is summed up, resulting in the total voltage of the system, while the amperage remains unchanged.

Example:

3 solar panels with a power rating of 6V/3A each will produce a total power output of 18V/3A when wired in Series.

2. Wiring Solar Panels of Different Voltages in Series

In this case, these solar panels have a similar current rating but different voltages. When wired in Series, the amperage remains intact while the voltage increases.

Example:

3 solar panels with a rating of 5V/3A, 7V/3A, and 9V/3A will produce a power output of 21V/3A when wired in Series.

3. Wiring Solar Panels of Different Amperage in Series

In this scenario, because the solar panels have different voltage and amperage ratings, the voltage will still be added up, but the amperage will automatically adjust to the solar panel with the lowest value represented.

Example:

3 solar panels with a power rating of 3V/1A, 7V/3A, and 9V/5A will produce a total power output of 19V/1A when wired in Series, reducing its efficiency drastically.

Advantages of Solar Panels in Series

One of the many advantages to a Series configuration is that it’s easy to transfer over long distances. Additionally, since the voltage is added up while the current remains the same, this allows you to save up on installation costs, as you can get away with smaller wiring.

Disadvantages of Solar Panel Series Wiring

The downside to having a Series configuration is that the amperage remains constant and unchanged leading to reduced efficiency. Furthermore, when connecting panels with varying power ratings, the panel with the lowest amperage rating will determine the total current output of the system. Lastly, if one solar panel gets damaged or has connectivity issues, the entire system collapses in a Series configuration.

2. Wiring Solar Panels in Parallel

A Parallel circuit is slightly more complex when compared to the Series circuit and has multiple paths for the current to travel along, as opposed to only one. This type of configuration is the complete reverse of a Series circuit because it increases your systems amperage (current), while keeping your voltage static.

Example:

3 solar panels with a power rating of 6V/3A each will produce a total output of 6V/9A when wired in Parallel.

Steps for Connecting Solar Panels in Parallel

The Parallel circuit is achieved by connecting all negative (-) terminals together and all positive (+) terminals together.

This will then leave you with one outstanding negative (-) and positive (+) terminal each, which will then connect to your batteries.

2. Wiring Solar Panels of Different Power Outputs in Parallel

In this case, the amperage will be summed up while the voltage will automatically adjust to the solar panel representing the lowest value.

For a solar system to effectively function in a Parallel configuration, the voltage must remain unchanged. This results in panels with a higher voltage dropping its rating to be the same output as the panel with the lowest voltage.

Example:

3 different solar panels with a rating of 3V/1A, 7V/3A, and 9V/5A will have a total power output of 3V/9A when wired in Parallel.

Advantages of Parallel Wiring Solar Panels

Parallel wiring configurations are best known for and commonly used in household solar systems. They allow for multiple paths of current to flow, irrespective of one broken or malfunctioning component. Parallel circuits are most used in Off-Grid solar systems and other 12V systems with multiple panels since the Parallel configuration allows you to keep your 12V charging capabilities while increasing your amperage.

Disadvantages of Solar Panel Parallel Wiring

A solar system wired in a Parallel configuration can be quite costly and time consuming to install, as it requires an additional amount of thick, heavy-duty wires to facilitate the multiple connections and handle the additional current. This type of configuration maintains a constant voltage output while increasing the amperage, however higher amperages require much thicker cables to travel long distances. Additionally, a Parallel circuit could require additional components such as branch connectors or a combiner box.

3. Combination of both Series and Parallel Connections

If you want to maximize the advantages of Parallel and Series wiring, you can combine the two circuits in your solar power system. Moreover, this option is used when needing to work around the limitations of a charge controller, since charge controllers are primarily designed to accept only a certain amount of amperage and voltage.

For this type of wiring, 2 or more panels need to be wired in Series, which creates a string. The the first string of panels must be connected in Parallel with another Series string.

This means that 4 panels in a Series configuration need to be Parallel with another 4 panels in Series to avoid any big power loss or connectivity issues.

Although there aren’t any disadvantages in a Series-Parallel configuration, it is equally important to know how to wire solar panels using this method.

Final Thoughts

It’s important to note that despite the various wiring options available, each configuration has its own pros and cons. It might seem easier to opt for the Series wiring, yet a disruption to one component that can affect the rest of the system making it less reliable for your intended use might have you thinking otherwise.

Ultimately, your choice of wiring will depend on the size of the installation, the location of the solar panels, the placement of the inverter, and whether you are setting up a grid-tied system or not.

We hope you find this article educational and helpful for your own solar system setup!