Is it better to connect solar panels in series or in parallel?

As RV enthusiasts, anyone who uses solar panels will generally only care about its power size. Few people will care whether it is monocrystalline silicon, polycrystalline silicon or amorphous silicon, and even fewer people will care about its series and parallel connection mode. The series and parallel connection mode of solar panels is one of the key factors that determine its power generation efficiency and stability.

1. Respective characteristics

Parallel connection is to connect the positive poles of multiple solar panels together, and the negative poles are connected together to form a bus. The current is superimposed and the voltage remains unchanged. It is suitable for situations where high current is required, such as wanting to speed up the charging speed of RV life batteries. It is more suitable to use the parallel method.

Series connection is to connect the positive and negative poles of multiple solar panels in series in sequence to form a long circuit. The voltage is superimposed and the current remains unchanged. It is suitable for situations where high voltage is required, such as long-distance power transmission, solar power stations, etc. If you only need to charge small devices, series charging is enough to meet your needs.

2. Comparison of advantages and disadvantages

 the power generation efficiency is different. When multiple solar panels are connected in parallel, the total current increases, which can increase the output power and improve the efficiency of the solar energy system, especially in low-light environments such as rainy days. When multiple solar panels are connected in series, the voltage increases but the current remains unchanged, which is suitable for power generation efficiency under sufficient light conditions. If there is a shadow, the output power of the entire system will drop sharply.

The second is different fault tolerance. The parallel method is suitable for a combination of multiple solar panels with lower power to avoid the impact of a single module failure on the entire system, because when a fault occurs in the parallel method, it will only affect the power generation of one solar panel, and the entire system can still work normally, with strong fault tolerance and relatively high reliability; the series method is suitable for a combination of a few solar panels with higher power. Once a solar panel fails, it will affect the work of the entire system, with poor fault tolerance and relatively low reliability.

The third is different system costs. The parallel method makes installation more complicated, requiring more and thicker connecting wires, which increases the manufacturing cost of the system. The series method reduces the length and resistance of the wires, has relatively low manufacturing costs, and is more economical and practical.

3, how to choose

In theory, solar panels can be connected in series or in parallel. In general, the choice of parallel or series connection requires consideration of actual use requirements, system design power, and the output power of solar panels. If you need to increase the voltage and transmission stability, you can use the series connection method; if you need to increase the output power, you can use the parallel connection method.

For RV solar panels, their use environment is special. On the one hand, there are more opportunities for the roof to be exposed to sunlight shadows. It is advisable to use the parallel connection method to reduce the impact of individual solar panel failures or sunlight shadows on the current to ensure that multiple solar panels can work at the same time. Especially when the RV is traveling outside, once a solar panel fails, the parallel solar panels only reduce the output power, which has a relatively small impact on the RV travel. The series solar panels will lose their power generation capacity, and the RV will lose the solar charging function when traveling outside, which has a huge impact. On the other hand, when the RV is traveling outside, it is necessary to speed up the charging power of the living battery in the car and reduce the dependence on good weather. It is also advisable to use the parallel connection method to ensure the output power of the solar panel.

Parallel connection has higher stability, and the circuit is not easy to be completely paralyzed. When the installation conditions are not affected much, the design and installation of RV solar panels should give priority to parallel connection, and then consider series connection.

Whether in series or parallel, try to use solar panels with the same specifications, confirm whether their peak power and open-circuit voltage and other parameters are the same, and ensure that the solar panels have a uniform rated voltage and rated current. In this case, the load of each component is equal, so as to avoid affecting the overall efficiency of the system. If solar panels of different specifications are connected in parallel or series, different solar panels may not match each other. Just like the barrel theory, the stronger solar panel will overcompensate the weaker solar panel. The solar panel with the worst efficiency is the power generation bottleneck of the entire system. The capacity of other solar panels with good efficiency will be seriously idle, thereby reducing the efficiency of the entire system and even damaging the solar panels.

Industry experience tells us that it is recommended not to exceed 4 solar panels in series or parallel. If more than 4 solar panels are connected, power loss and voltage drop may occur.