If you are interested in the photovoltaic sector and are about to build a system, you may have had the doubt of whether it is better to install Solar Panel Series vs Parallel.
To learn more about these two types of connection between modules and to understand which one is best for you, continue reading!
First of all, let’s start by saying that there are 2 ways to connect photovoltaic modules together: in series or in parallel. Do you know the main differences between the two?
Connecting photovoltaic panels in series
How to connect photovoltaic panels? One of the two methods of photovoltaic wiring between modules is precisely series one.
Connecting modules in series is quite simple because it does not require the use of additional tools. All you have to do is connect the positive terminal of the first module to the negative terminal of the next.
Proceeding in this way with the other modules creates a series-connected string that can contain up to 20 photovoltaic modules. With series wiring, you will only need one wire to connect all the panels in a string together.
In a series connection, the voltages produced by each individual module are added together. This means that the sum of the output voltages of each module gives the total output voltage of the array. The current, however, remains the same as that produced by a single module.
Here’s a little example: If we connected 3 panels in series with a voltage of 6V and a current of 3A, the final string will produce a total output voltage of 18V (6+6+6) at 3A.
As you may have understood, series wiring is used to increase the total voltage of the system. This is because in a PV system, for the same power, the higher the system voltage, the lower the current.
Consequently, the energy losses along the cables will be lower. Furthermore, considering that the current does not increase because the amperage of each module remains unchanged, it will not be necessary to use larger cables.
Photovoltaic panels in parallel
Unlike the series connection, for the parallel connection a single cable is not enough to connect the modules. Here the matter becomes a little more complicated. The connection is made by connecting the positive terminal of a module to the positive terminal of another with a first wire and proceeding in a similar way with the negative terminals of the same modules using a second wire.
This type of connection is used when you need to obtain a higher output current at the same voltage. Here, in fact, the total output voltage remains the same as that produced by each individual module, while the currents of each panel are added together.
Returning to the example used for the series connection, if we connected 3 modules of 6 V and 3 A in parallel, the total voltage of the system would remain equal to 6 V, while the total output current will be 9 A (3 + 3 + 3).
Are photovoltaic panels better in series or parallel?
So? Is it better to install photovoltaic panels in series or in parallel? It depends. The series connection brings significant advantages such as a simple and quick installation, without too many costs, a higher overall voltage and therefore the possibility of using cables of reduced thickness (consequently cheaper) and having lower energy losses.
However, the series connection has a downside. In fact, if the area where the system is going to be installed is subject to shading (due to the presence of trees, chimneys or other), this type of connection is not ideal.
In a string of panels, if only one of them produces less power than the others due to shadows or incorrect orientation, the entire string will suffer because the least efficient panel will affect all the others. This means mismatch losses could occur across the entire string if a single module is completely shaded.
In a set of modules connected in parallel, however, shading is not a problem. If a single module produces less, this does not affect the efficiency of the other photovoltaic modules.
Therefore, the choice of the most appropriate type of connection must be made based on the type of installation, orientation and position of the system modules. In any case, the characteristics of the installed inverter will determine the maximum usable current and voltage of the string.
In short
Series connection: the total current of the group of modules remains unchanged, while the sum of the voltages of the individual modules gives the total voltage.
Parallel connection: in this case the current of each module is added, while the voltage remains the same as that of the single module.
How to connect photovoltaic panels to each other: The choice between installing photovoltaic panels in series or parallel depends on various factors in the system.