There is always the doubt about how solar panels should be connected to obtain better performance. Next we will analyze how the connection of solar panels in series and parallel is made.
Panel connection in series and parallel
There are many types of solar panels available on the Polish and world market. Starting with small modules of 5W – 160W dedicated to systems with gel batteries and other more powerful ones with a power greater than 280W and more, destined to solar power plants connected to the electrical grid, but also to battery systems.
Of course, these panels are divided into polycrystalline and monocrystalline structures, but we will not talk about this today. Solar panels , if we have more than one, can be connected in series and in parallel. Which method is better and more efficient, why connect solar panels in this way. We will try to answer these and other questions in our article.
Connection of solar panels in series.
Each solar panel has two more important parameters, the voltage expressed in Volts [V] and the current expressed in Amps [A]. The result of your product gives us the power expressed in Wato Pikach [Wp]. When we connect solar panels in series, that is, we connect several panels with each other, more and less are left at the ends with two more and less cables. With photovoltaic modules connected in this way, their voltage will increase by the product of the volts of a solar panel and the number of panels connected in a series. The current will remain the same and the power expressed in watts will be as the voltage, the product of the power of a photovoltaic module and its number.
Why connect solar panels in series?
Why do we connect solar panels in series? First, to increase tension. By increasing the voltage, the system gains efficiency. A similar example can be found in the energy sector. Raising the voltage on high voltage lines up to 100,000 volts allows the transmission of power over long distances with minimal losses using relatively small cables at the same time. Of course, here we have alternating voltage and direct voltage in panels, but the concept of power for both systems is the same.
High voltage solar panels are used by domestic solar power plants . Depending on the inverter used, the voltage can range between 180 V and 900 V. The change from high voltage to low voltage in this case alternating current of 230V occurs with much greater efficiency and with lower losses.
High voltage is also a better performance of the MPPT solar panel energy tracking system. Grid inverters continually check at which point, at any given time of day and in sunlight, the highest voltage and current are in the panel string. Thanks to this, I significantly optimize the work of the entire solar power plant.
The connection of solar panels in series is also used in photovoltaic systems equipped with batteries. In this case, however, there is rarely a situation where the solar panels are connected by more than 4. The advantage of such a system is the fact that the MPPT system does not include the voltage from the solar panels. to battery voltage, so it does. do not limit the power of the solar panels in any way. Traditional PWM systems can reduce panel power by up to 40%
Connection of solar panels in parallel.
Parallel connection of solar panels is done by connecting all cables together according to the principle of advantages with advantages, disadvantages and disadvantages. Such a connection does not increase the voltage, only the current. Power, as in series connection, is the product of the power of a photovoltaic module in relation to its number in the connected system.
The parallel connection raises the current expressed in amperes. In such a situation, it should be taken into account that the overall efficiency of the system decreases and it is necessary to use appropriately thick cables and at the same time as short as possible to avoid losses during power transmission. A good example is a high power voltage converter . It always has finger-thick wiring with a maximum length of 50-60cm.
Why connect solar panels in parallel?
Parallel connection is usually done when our charge controller works on PWM system, so it contains the voltage from the solar panels to the battery voltage. In such a situation, we cannot exceed the voltage of 30V or 50V for 24V systems and we are forced to connect the panels in parallel. It also occurs in solar power plants where there are a large number of panels and the voltage exceeds 1000V.
However, it must be remembered that the parallel connection of solar panels always leads to a reduction in their efficiency and large drops in power transmission. Therefore, as far as possible technical and financial possibilities are concerned, it is worth looking for MPPT systems that do not limit the power of solar panels.
Can two different solar panels be connected in series?
However, this configuration is theoretically and practically not recommended. Please note that after connecting two different solar panels, one with a power of 300W and the other with a power of 320W, both will work with the same power as the weaker panel. However, this is a much better solution than using a PWM charge regulator, which significantly limits the power of the PV modules based on the battery voltage.
When connecting two solar panels of different powers, make sure that the operating voltage at the power point is similar. For small panels up to 180W 18V, for large solar panels around 32-36V depending on the model and power.
Can two different solar panels be connected in parallel?
Yes, and as long as we take care of a similar voltage at the outlet, it is possible to connect solar panels with different powers. In such a connection, the sum of the currents expressed in amperes [A] will be added. However, the PWM charge controller must be used because the MPPT controller will reduce the string power * to the power of the weakest module, which can lead to losses even greater than the losses resulting from the limitations of the PWM system.