Connecting Solar Panels: Series vs Parallel

Are you looking to harness the full potential of solar power? If so, understanding the intricacies of solar panel wiring is crucial. Fortunately, we’ve got you covered. In this comprehensive article, we will delve into the fundamental concepts of connecting solar panels, exploring the options of series and parallel configurations. With a focus on clear and informative language, we aim to provide you with the knowledge and confidence to make informed decisions about optimising your solar panel system.

As the world moves towards a greener future, renewable energy sources like solar power have become increasingly popular. However, not everyone is familiar with the technicalities of solar panel wiring. That’s why we’ve created this guide, to help you make the most out of your investment in solar power. Whether you’re a seasoned solar enthusiast or a newcomer to green energy, this article will guide you through the essentials of solar panel wiring, helping you choose the best setup for your specific needs. With our easy-to-understand explanations and expert advice, you’ll be able to make informed decisions about your solar panel system and take a step towards a more sustainable future.

Key Takeaways

• Solar panel systems offer a flexible and sustainable energy solution, with prices expected to compete favourably with traditional fuels by 2030.
• The choice between series and parallel connections for solar panels significantly impacts the system’s performance and reliability.
• Series connections increase voltage but can be affected by shading and reliability issues, while parallel connections increase current and offer flexibility, especially for smaller systems. A combination of both series and parallel connections can balance efficiency and reliability based on specific requirements.

Basics of Solar Panel Wiring

Wirings play an essential role in a functional solar panel system. This process is also known as Stringing. Every series of panels connected is called a single string.

Before we dive into different types of wiring, let us look at the essential elements of the connection setup.

Solar wiring uses wires to link all of the panels in a solar array to form a circuit through which electricity travels. The line is connected to an inverter, which converts DC into usable home AC power and sends it to the grid.

Wires and cables used in solar wiring uses are not your regular ones. They are resistant to heat, moisture, water, and UV with different insulations based on the placement of panels. Although used interchangeably, wires are different from cables. A solar wire is a single conductor, while solar cables are a composite of several conductors or wires held together by an outer jacket and are more heavy-duty.

Different wiring configurations need knowledge of how they affect the performance of solar arrays’ voltage, current, and power. Stringing can be done in two options to make the best of your solar panels.

Solar Panel Connection: Series vs. Parallel Wirings

You have three ways of connecting solar panels to create a functional power setup to provide solar electricity to obtain the desired power for your house.

1. Series connection
2. Parallel Connections
3. Combination of both series and parallel

Connecting Solar Panels in Series

Series panels involve current travel in a single direction along the circuit. This makes all the current in the circuit flow across all the connected loads. A series circuit is continuous and has a closed loop. That means the entire series stops functioning when you break the circuit at any given point. A classic example would be a steam iron or old models of string lights – where the entire set would be affected when one snapped. You would need to locate and replace the defective bulb to get the lights working.

Picture a regular battery – it has a negative and positive terminal. The same is the case with solar panels. The wire from the positive terminal of one solar panel is connected to the negative terminal of the one next in line, and so on, to create a series connection.

Increased Voltage, Same Current

You add the voltages in a series panel, but the amperage (current) does not increase. That means each panel adds to the overall voltage of the string while the total current is the same. The series’ benefit is that it is easy to transfer over long distances.

When wiring solar panels in a series, the voltage is additive, but the current remains the same. For example, if you installed five solar panels in a series, each rated at 14 volts and five amps, the entire array would be 70 volts and five amps.

A principle to note is that lower voltages refer to higher currents, and higher voltages mean lower currents. This is key for panels, especially aligned in a series connection, as this configuration shoots up the voltage every time you install an additional panel. Hence, the total current across the system is lower.

This setup increases savings with smaller wires and shorter cables, making the solar panel system more efficient and reducing electrical losses.

A recurring downside to series solar connections is the problem of shading. When panels are strung in series, they are interdependent as the current flows from one string to another. In the event of shading, even on one panel, the whole string gets affected and reduces in power load.

Disadvantages

Series connections also carry reliability issues as all strings are connected with one main wire. Should the same fail, the entire system shuts down instantly.

Overcoming Disadvantages of Series Connection

While you cannot solve the reliability issue, using a micro-inverter for every individual panel provides the best solution to shading, as every panel will be independent of the other one for its power support. In this way, the shading of one panel will not affect the overall power output of the whole solar system.

When Should You Install a Series Connection?

• A general presumption is that a series connection is the best choice for higher voltages.
• It is also a wise choice when the inverter and solar panels are placed far apart. This allows the system’s voltage to adjust and increase to equal the inverter’s voltage input.

Connecting Solar Panels in Parallel

Parallel connections in solar panels imply wiring all the positive and negative terminals separately. The dual connections are then linked to the inverter of the solar panel system to generate power.

In a parallel connection, the positive terminal from one solar panel is connected to the positive terminal of another panel, and the same is done with the negative terminals. The positive wires are matched to a positive connector within a combiner box, and the negative wires are connected to the negative counterpart. A PV Output Circuit is formed when several panels are wired parallelly.

Increased Current, Same Voltage

Unlike a series system where voltage increases, it remains the same in parallel wiring. You add the amperages together and keep the voltage the same across arrays.

Because of the separate connections of positive and negative terminals, parallel strings reduce the overall effect of shading on solar panels. Even when one panel is heavily shaded, the remaining panels can operate normally unaffected. The system does not shut down as the current flow of the rest of the string is not reduced.

Wiring solar panels in parallel gives you the flexibility to have an extra set of solar panels to produce more energy. As the voltage is kept low, you can quickly meet the voltage limits of the existing solar power inverter without getting a new one to match increased production.

Disadvantages

Running an electrical circuit with high amperage requires thick cables to carry the load. Imagine the thickness of a water pipe that gushes a large volume of water through the system. Parallel connections also require wires and cables that support heavy-duty current flow.

Apart from that, they are also more complicated and expensive to install.

When Should You Install a Parallel Connection?

It is usually advised to set up a parallel connection when the system area is relatively smaller and caters to low supply loads or has a battery with a low voltage requirement.

Combination of Series-Parallel Connections

Now that enough is said about both series and parallel connections in a panel let us look at the result when both setups are included in one array.

Establishing the connection according to the voltage and the current input range of an inverter or a charge regulator is often necessary.

There may be instances you don’t get close to getting the ample voltage and current range by solely configuring a series or parallel connection. A series connection could exceed the voltage limit. With a parallel connection, you can increase the current limit while limiting the supply of high active power through the configuration.

When you include both solar panels in a dual fashion of series and parallel, the voltage in each string combines while the current (or amps) remains the same.

Then, the voltage in the two strings stays the same while the amps are added together. Combining both types gives the advantage of a series connection, i.e., reduced electrical losses with reduced costs and a parallel connection’s reliability.

Case Study: Optimising Solar Panel Wiring for Maximum Efficiency

Background

At Solar Panels Network, we specialise in designing and installing solar systems tailored to our clients’ specific energy needs. This case study details a project where we optimised the wiring configuration for a residential solar panel system, ensuring the best balance of efficiency and reliability.

Project Overview

The project involved a suburban home, where the homeowner sought to install a solar panel system that would significantly reduce their electricity bills and ensure consistent energy supply. After conducting a site assessment, we recommended a mixed wiring configuration of series and parallel connections to meet the household’s unique requirements.

Implementation

• Initial Assessment and Planning: The property featured a roof that allowed for multiple panel placements, with some sections potentially affected by shading from nearby trees. We designed a system that included both series and parallel connections to optimise energy production and reliability.
• System Design and Configuration: The system comprised 12 solar panels, divided into two series strings of six panels each. These series strings were then connected in parallel to form a unified system. This configuration was chosen to balance the need for high voltage, required for efficient power transfer, and increased current, which enhances the system’s overall capacity.
• Installation Process: Our team installed the system over three days, ensuring all components, including an inverter and monitoring system, were correctly set up. The use of high-quality, UV-resistant cables and robust mounting structures ensured durability and optimal performance.
• Maintenance and Support: We provided a comprehensive maintenance plan, including annual inspections and real-time performance monitoring. This plan ensures that the system operates at peak efficiency, with minimal downtime or performance loss.

Results

• Enhanced System Efficiency: The mixed series-parallel configuration successfully maximised the system’s efficiency, allowing for optimal voltage and current levels. This setup ensured that even when some panels were partially shaded, the system continued to operate effectively, without significant drops in output.
• Financial and Environmental Benefits: The homeowner reported a reduction of approximately 50% in their electricity bills, translating to annual savings of around £600. Additionally, the system’s design helped reduce the household’s carbon footprint by nearly 1.5 tonnes of CO2 annually.
• Improved Reliability: The combination of series and parallel wiring improved the system’s resilience to shading and other potential disruptions. This reliability is crucial for ensuring a steady power supply and maximising the return on investment.

Summary

This case study demonstrates the importance of choosing the right wiring configuration for solar panel systems. By employing a mixed series-parallel setup, we ensured the system’s efficiency and reliability, providing significant financial and environmental benefits to the homeowner. At Solar Panels Network, we continue to deliver customised solar solutions that meet our clients’ energy needs and sustainability goals.

Expert Insights From Our Solar Panel Installers About Connecting Solar Panels

Understanding the difference between series and parallel wiring is crucial for optimising your solar system. Series connections are great for boosting voltage, making them ideal for long-distance power transfer. However, shading on one panel can affect the whole string.

Senior Electrical Engineer

Parallel connections, on the other hand, are excellent for maintaining consistent system performance even if some panels are shaded. They increase current and offer greater flexibility, particularly useful for smaller or irregular systems.

Lead Solar Technician

Combining series and parallel configurations can be an effective way to balance voltage and current, especially when the system requires a specific power range for inverters or charge controllers. This approach maximises efficiency and reliability.

Chief Installation Specialist

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Summary

Having a good idea about the differences between serial and parallel connections would be best. You must pick an ideal system based on your specific use and roof area.

A parallel connection is probably the most efficient for solar panels of different capacities. If your system is more than 20 feet away, then a series connection is feasible. Whether solar arrays are to be connected in series, parallel, or combination depends on your specific expectations from the solar panel system. These different wiring configurations affect the voltage and current in the panel circuit.