Connect solar panels: in series or parallel

More and more people nowadays are choosing to switch to photovoltaics. The decision to install solar panels on your roof is advantageous from many points of view. Some people also use ground mounted solar panels. First of all, you will have the opportunity to produce clean energy to power your home’s utilities and, therefore, considerably reduce bill costs. This is because, thanks to your self-consumption, you will be able to become increasingly independent from the national electricity grid precisely because you will be able to take advantage of the energy you will produce through your system.

Today we will explain how to connect your solar panels on the roof of your house. Did you know that they can be connected in series and parallel? Discover this and much more by continuing to read our article!

Connect solar panels: in series or parallel

When installing a photovoltaic system in a domestic environment, it is necessary to adjust the voltage levels and output current correctly. This regulation determines the configuration of the circuit and the type of connection of the solar panels to each other.

Below we will explain what connecting photovoltaic modules in series or similar means, the main differences, and installation methods.

Series connection of photovoltaic modules

As mentioned, the first way of connecting solar panels to each other is in series, and this involves connecting the positive output of one module to the positive output of another. Proceeding similarly with the other panels, it is thus possible to create a string connected in series, which can include, on average, 2 to 20 solar modules.

The exact number of photovoltaic panels connected in series depends on their type, the components connected to them, and other constraints. When several panels are connected in series, the voltages of the individual modules are added together while the currents remain unchanged. So, for example, by connecting 5 12V and 4A panels in series, you will have an output voltage of 60V and a current of 4A. Since voltage and current are known, it is possible to calculate the power supplied by the string with the formula W = V x I: 60 x 4 = 240 W.

Find out in the next paragraph how the panels are connected in series!

Parallel connection of solar panels

The number of solar modules connected in series is relatively limited. Therefore, to obtain more power than a string of panels in a series can provide, connecting several strings in parallel, each made up of the same number of modules, will be necessary.

The parallel connections of solar panels are complementary to those in series and are made by connecting the positive pole of a module (or of a string) to the positive pole of another module (or of another string); we will proceed similarly also with the negative poles, which will also be connected.

When PV panels are connected in parallel, the system voltage remains the same while the currents add up. So, to give an example: if you connect 5 12V 4A modules in parallel, you will have an output current of 20A at 12V, and the power supplied by the system will be, using the formula W = V x I: 12 x 20 = 240 W, i.e., the same value obtained with the series connection.

However, it is important to make some specifications concerning this particular type of connection. If you have two solar panels of equal voltage and power, the connection will be very simple. We also remind you that this connection is efficient if the following conditions are met:

  • The photovoltaic panels are close to each other and oriented at the same angle;
  • The modules do not shade each other and are as far away from shading causes as possible;
  • The section of the electric connection cable is of the right size based on the distance of the panels;
  • Junction boxes connect the terminals of the solar modules neatly.

If you have two photovoltaic panels of equal voltage but different power, you can connect them in parallel. However, it is not the case if the two solar panels have different power and voltage. In this case, it will not be possible to connect them in parallel since the one with the lower voltage would behave like a load and would begin to absorb current instead of producing it.

Is it better to connect in series or parallel?

Is a series or parallel connection better for your solar system? The answer is: it depends. As seen throughout this article, 5 hypothetical solar panels connected in series or parallel provide the same power. Therefore, you will connect the modules in such a way as to obtain the desired voltage while increasing the current with parallel circuits to obtain the desired power from the system.

Sometimes, a home solar system kit combines parallel and series connections. In practice, one or more strings of panels connected in series to increase the output voltage are connected in parallel to increase the current and, consequently, the output power in watts.

Frequent questions

How many solar panels can be connected in series?

Connecting a string of panels in series means connecting one module’s positive output to another’s positive output. A string can be connected by proceeding similarly with other panels, which can typically comprise from 2 to 20 panels.

How are photovoltaic panels connected in parallel?

How are solar panels connected? series vs parallel? To connect the solar panels in parallel, it will be necessary to connect the positive pole of one module to the positive pole of the other and the negative pole to the other negative pole.

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