Today, a large number of Chinese solar modules are presented in our market, but few of them have passed a certification test. Our “Yingli Solar” solar modules are made of high quality elements, which is confirmed by the German TÜV SÜD certificate.

Note that none of the major manufacturers of solar modules indicate the cell quality (Grade) on the module (and the label "Application Class A" is not related to the quality of the elements, but indicates the electrical safety class of the panel. "Security class A" allows you to use panels in industrial power plants, modules with voltage up to 1000 volts, today up to 1500 V). The TÜV mark on the sticker can be checked from the certificate database by entering the manufacturer name, for example, Yingli Energy (China) Co., Ltd

There are 3 main degrees of solar cell quality.

Grade A - After the accelerated aging test (PID test), the power of the elements is reduced by no more than 5%,  that is the cells continue to produce more than 95% of their nominal value.

Grade B - After the accelerated aging test (PID test), the power of the elements is reduced by no more than 30%, the cells continue to produce more than 70% of their nominal value.
Grade C - After the accelerated aging test (PID test), the power of the elements decreases up to 30%, the cells continue to produce less than 70% of their nominal value

Solar panels are often made of Grade B or Grade C elements. Moreover, when we buy them, they may correspond to the declared parameters (although there are cases of false indication of the panel parameters), and probably it is visually difficult to distinguish them from panels with high quality Grade A elements. However, during operation, due to the effects of high temperatures and humidity, especially when a large number of panels are connected in series (that is at high voltage), Grade B or Grade C elements quickly lose power, leading to malfunction of all solar panels or cessation of production within a few years.

PID test or Potential Induced Degradation Test - this is an attempt to degrade solar cells with the help of high potential.

The test is performed for 96 hours at a temperature of 60 ° C, 85% humidity and on the basis of a solar panel equal to 1000 volts compared with the potential of solar cells.

Before and after the test, the energy measurement of solar panels and Electromagnetic tests are carried out. According to the test results, a conclusion is made about the quality of solar cells.

The article was published in 18.10.2018

Last updated in 27.07.2020