Series vs. Parallel Solar Panels: How To Connect Modules Correctly

Series vs. parallel solar panels: what does this mean? Let’s try to figure it out together. Recently, the number of U.S. households using solar panels has grown hundreds of times and continues to increase. For clarity, we present statistics from cumulative U.S. residential solar capacity from 2010 to 2022 (in megawatts):

Solar power capacity installed across United States' homes (in megawatts) from 2010 to 2022

Source: Statista

Accordingly, the topics of parallel-wired solar panels vs. series-wired and understanding how to wire solar panels are relevant among household users.

Connecting solar panels may seem like a daunting task at first glance. But making the correct installation doesn’t have to be challenging, especially if you understand the basic principles of current and voltage distribution.

Carefully studying how to wire a solar panel will help you achieve the desired result, such as determining the future configuration of solar panels and creating the most energy-efficient system for specific purposes.

Looking to compare features and prices for solar panels wired in series vs. parallel? Don’t waste another minute — get your free solar quote right away!

Basic Concepts Parallel vs. Series Connections in Solar Panel Configuration

There are three main but very different ways of connecting solar panels. Each is designed to obtain specific output parameters of voltage, current, and power.

Solar panels can be connected as follows:

  1. Serial connection: The method is used to increase the output voltage parameter.
  2. Parallel connection: Helps to increase the output current parameter.
  3. Connection series vs. parallel solar panels together: This method increases the voltage and current outputs, creating a higher power array.

Here’s a simple rule to remember: you can connect solar panels with the same operating current in series, but panels with the same operating voltage must be connected in parallel.

When connecting solar panels in series, the voltage is summed up, but the current remains unchanged. The current is summed when connecting solar panels in parallel, but the voltage remains unchanged.

Next, let’s look at the features of connecting solar panels in series vs. parallel.

How To Wire Solar Panels in Series and How It Affects Voltage and Current

When solar panels are connected in series, the voltage in the circuit is summed up. The current in such a circuit corresponds to the current of one of the panels with the lowest value.

 A graphic explaining how to wire solar panels in series

Source: Electrical Technology

This configuration is applicable when you need more voltage to operate powerful equipment, such as a refrigerator or washing machine. Moreover, the more panels are wired in series, the higher the voltage parameter can be obtained.

Pros of connecting solar panels in series Disadvantages of connecting solar panels in series
Higher output power helps solar cells charge faster and save energy. The overall performance is determined by the lowest performance of one of the panels (if one of the panels does not work correctly, then the others work similarly)
Low overall current eliminates the need for bulky cables. An inverter resistant to high voltage is required for connection.
Significant voltage reduces power loss. The panels can only be oriented in one direction.
Effective in shaded conditions.

 

Pro tip: when connecting solar panels in series, make sure all components are identical (same model, same manufacturer, etc.). A slight deviation in the parameters of just one panel may affect the output of the entire circuit and, accordingly, the energy efficiency of the array.

How Parallel Connection of Solar Panels Impacts System Performance

If you connect solar panels in parallel, the voltage at each panel’s output will equal the voltage at the output of the entire array. The current strength will be summed up.

A graphic showing how to wire solar panels in parallel

Source: Electrical Technology

Pros of connecting solar panels in parallel Cons of connecting solar panels in parallel
Incorrect operation of one panel does not affect the operation of the entire array. It requires more wires and other powerful equipment to handle the high current.
The configuration is optimal for small, low-voltage systems (e.g., a caravan). The voltage parameters of solar panels must have the same values ​​for the safe operation of all arrays.
The connection works well in conditions of combined illumination with occasional shading.
Less risk of electric shock due to low voltage.

 

Thus, the parallel connection of the solar panels allows you to increase the amount of energy received at the output of the array.

Combining Series and Parallel Solar Panels

It’s not uncommon for homeowners and solar enthusiasts to doubt both connection methods. But constantly comparing series vs. parallel solar panels and weighing the pros and cons of these methods can be time-consuming and exhausting.

For those struggling to make a decision, we offer the next best alternative — combined wiring. This method allows you to achieve an optimal balance between voltage and current.

A graphic showing how to wire solar panels in series-parallel

Source: Electrical Technology

Pros of connecting solar panels in combined series-parallel configuration:

  • Voltage: In groups connected in series, the voltage adds up.
  • Flow: In groups connected in series, the current strength adds up.

With a combined connection, you solve two problems simultaneously: you increase the voltage and current of the entire system of solar panels, which cannot be achieved in any one way.

Output Voltage and Current in Series and Parallel Solar Panel Configurations

Such connections give certain voltage and current values ​​at the output of the solar power system. However, there is a big difference in the output data if you use solar panels with various parameters.

1. Differences in output voltage and current when connected in series with different parameters of solar panels

If you use panels with the same or different voltage values but the same current strength, the output voltage will be equivalent to the sum of the voltages of all solar panels. The output current will remain equal to the current of one panel.

If you use panels with different voltages and currents are used, the output voltage will be equivalent to the sum of the voltages of all solar panels. The output current will be equivalent to the lowest current of one of the panels.

2. Differences in output voltage and current when connected in parallel with different parameters of solar panels

If panels with the same voltage values ​​and different or the same current strength are used, then the output voltage will be equivalent to the voltage of one of the panels. In this case, the output current will be equal to the sum of the currents of all solar panels.

If panels with different voltage values ​​are used, the output of the total array voltage will be set somewhere between the lowest and highest. Therefore, with a parallel connection, solar panels must have the same voltage ratings to be used safely and effectively. So, the power of the entire array depends on the specific output voltage and current data of solar panels.

How To Choose Between Series and Parallel Connections When Installing Solar Panel Systems

To choose between two connection methods for solar panels, you must:

  1. Assess system requirements
  2. Determine the required output power

If solar panels are located in an unshaded location most of the time, it makes sense to use a serial connection.

A parallel connection is an excellent solution if you need solar panels for traditional lighting.

Performance of Solar Panels in Series and Parallel Connections in Shading Conditions

Scan panels should be placed facing south, with a deviation to the east of no more than 20 degrees and the west of no more than 30 degrees. Clouds, trees, nearby buildings, dirt, dust, and other debris usually cause shading.

Under the influence of a large shadow, the voltage on the shaded panel decreases. In light shade, for example, the current strength is reduced. If solar panels are connected in combination (series-parallel), the shadow of a tree falling on one of the panels has no effect on the entire system.

Maintenance and Repair of Series and Parallel Solar Panels

Solar panels have a reliable and durable design. But they can also fail or operate less efficiently. For the solar power plant to run at full capacity, perform regular maintenance and identify and eliminate operating irregularities.

The frequency of cleaning solar panels depends on many factors, such as location, weather conditions, and environment. As a general rule, solar panels should be cleaned at least once or twice a year.

The lifetime of solar panels depends on their quality. Therefore, they should be purchased from trusted suppliers. All you need to do is monitor the output parameters. Suppose the inverter shows an error or lack of generation. In that case, you must contact the company’s representatives who did the installation.

Looking to compare features and prices for solar panels wired in series vs. parallel? Don’t waste another minute — get your free solar quote right away!

Frequently Asked Questions

What factors should you consider when choosing between solar panels in series or parallel?

When comparing series vs. parallel solar panels and selecting the preferred connection method,  you should assess your specific needs and overall system requirements. It is also important to study solar panels circuits (for example, review parallel vs. series solar panels diagram).

The main factors to consider when picking solar panels in series and parallel are output voltage, current, and power, as well as available space and module compatibility.

How do series and parallel connections affect the efficiency of solar panels?

Largely effective solar panel connection depends on the quality of the panels, correct installation, cleanliness of panels, level of shading, angle of inclination, and other factors.

Can I combine series and parallel connections in one solar panel system?

Uniting series and parallel connections together is quite effective. The combined method can be achieved by combining series-connected paired panels using a parallel method. As a result, current and voltage increase in multiples of the number of elements divided by two.

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