What Is the Difference between Photovoltaic Panels Parallel & Series Connection?

Photovoltaic panels differ in their ability to connect components. Photovoltaic cells can be combined in two ways: parallel and series. Each has different features, such as how to connect photovoltaic panels.

What are the characteristics of both types of modules?

Methods of connecting photovoltaic panels

Each photovoltaic installation consists of one or several rows of modules fastened together in chains called strings. How they are mainly connected determines the voltage and current that will reach the inverter or microwave.

The voltage and current reaching the inverter are also determined by atmospheric conditions, i.e., the degree of sunlight, as well as the frequency of cleaning of photovoltaic panels, which significantly impacts the efficient functioning of the entire installation.

There are two ways to connect photovoltaic modules:

• Parallel connection of photovoltaic panels;
• Series connection of photovoltaic panels.

Both parallel and series connections of photovoltaic panels have advantages that enable efficient operation. A professional assembly company always decides how to connect the modules, considering the type of inverter and possible further investment expansion plans.

What is the parallel connection of photovoltaic panels?

Parallel connection of photovoltaic panels involves connecting all their cables on the principle of pluses and minuses with minuses. Thanks to this, the voltage in the entire circuit is the same as that declared for a single-cell module, but the current is added up. This connection type is used where increased power efficiency is required.

Parallel connection of photovoltaic panels is used primarily in low-voltage installations, where each module has a separate inverter. This solution causes the voltage flowing through the solar cells to be low: this type of installation is equipped with microwaves.

This type of connection is also used in high-power photovoltaic installations, where it is necessary to connect many strings and use inverters with a broader input current range.

Advantages and disadvantages of parallel connection

The parallel connection of photovoltaic panels determines the voltage and current in the entire circuit. Learn about the advantages and disadvantages of this solution.

Advantages of parallel connection:

• Higher efficiency in the case of partial shading — in this type of connection, each photovoltaic module operates independently of the others, so in the event of contamination, damage, or a reduced amount of sunlight reaching one of them, the others work with unchanged efficiently, thanks to which the operation of the entire installation is not disturbed;
• Possibility of easy expansion of the installation and replacement of individual modules — in parallel connection, each module works independently of the others, so replacing a single cell is not troublesome. In addition, if necessary, you can easily expand the entire installation;
• Lower risk of electric arc formation in the installation — lower voltage current flows in parallel installations. Thanks to this, the risk of an electric arc leading to ignition of the entire PV installation is much lower.

Disadvantages of parallel connection:

• Increased risk of energy losses — in parallel connection, the current flowing intensity is increased, affecting the installation’s efficiency. This causes a greater chance of energy losses during power transmission. It is worth using thicker and longer cables during installation to avoid such a situation.

Parallel connection of photovoltaic panels has many advantages that determine the high efficiency of the entire installation. However, before you decide to use it, consider all the features of this type of joint.

What is the series connection of photovoltaic panels?

Connecting photovoltaic panels in series involves connecting their cables according to the pluses and minuses principle. This connection causes the voltage in each circuit to increase while the current in a single string remains the same as in one module.

This type of connection was widely used. It was used both in home installations and in enterprises. The heart of the entire series-connected system is a series inverter — also called a string inverter — which manages the operation of all modules. This means the more panels are connected in a series, the more voltage reaches them.

Connecting PVs in series allows you to achieve greater efficiency for the inverter and the entire installation. In this type of solution, converting direct current into alternating current can be performed more efficiently and with lower energy losses.

Advantages and disadvantages of series connection

The PV series connection is viral. In this type of joint, each module’s operation directly affects the others’ efficiency. What are the advantages and disadvantages of such a solution?

Advantages of series connection:

• High system efficiency — in series connection, the voltage in each circuit is increased, which increases the efficiency of the entire system. The string inverter accepts a DC voltage of several hundred volts, and a current of 230 V is transmitted to the electrical installation. The conversion from higher to lower voltage is faster;
• Reduced energy losses — in series connection, losses related to energy transmission are lower because smaller wire cross-sections are used;
• Reduced cost of converters — in this type of connection, one inverter connects several modules, but it is possible to connect even several dozen of them. In a series connection, there is no need to use microwaves, which are a more expensive solution.

Disadvantages of series connection:

• Reduced efficiency in the event of shading — in series connection, the operation of one module affects the efficiency of the entire installation; therefore in the case of partial shading, dirt, or damage, productivity is reduced;
• There is a greater risk of electric arc formation in the installation — in series connection, the DC voltage is higher, which increases the risk of electric arc formation.

Suppose you are planning to install an extensive photovoltaic installation or want to do it in the future to build an energy-efficient house. In that case, PV series connection is the solution for you. However, before making the final decision, consider all the advantages and disadvantages of such a solution.

Can you combine photovoltaic panels with different powers?

Connecting photovoltaic panels with different power is not recommended, either in series or parallel. This is because, in both types of joints, the modules with the worst parameters will affect the efficiency of the remaining ones, ultimately reducing the efficiency of the entire installation.

However, this possibility is provided by parallel connection of photovoltaic panels, but only if microwaves are used separately for each module. This means that each micro-inverter works individually, so using solar panels with different powers will not affect the efficiency of the others.

Which connection type should I choose?

Both series and parallel PV wiring have their advantages and disadvantages. Before deciding to use one of them, consider factors such as the location of the installation, the type of inverter, and the desire for further expansion.

If you are unsure what type of connection to use in your installation, seek help from professionals who will advise you in making the best decision, presenting in detail the advantages and disadvantages of each solution.

You may also read:

• What Are The Benefits Of Installing A Solar Panel System In The Home?
• Major Technologies for Smart Grid Implementation