Typically, dramatic cost savings are achieved through the use of cheap materials and savings in factory final inspection procedures. Unfortunately, some internal defects cannot be detected without special equipment. But most of the obvious signs of poor quality are easily detected even with a superficial visual examination.
How to visually check a solar panel for performance
According to the type, number and severity of external defects, all photovoltaic panels are usually divided into four quality categories.
1. Grad A.
Premium class. It characterizes the products of the companies that are constantly at the top of the prestigious world TIER-1 rating from Bloomberg. Is different:
ideally uniform structure of the cell surface;
lack of color overflows, gradation of shades and emerging diffraction under the rays of the sun;
absolutely homogeneous protective coating, without a single microcrack, chipping and other damage;
The service life of such modules is maximum, and the likelihood of the PID effect is practically zero.
2. Grad B.
Second category. Slightly inferior to the elite. If you visually check such a solar panel, you can find:
a barely noticeable change in the degree of color saturation in different places of the panel;
absence of visible mechanical defects on the glass;
completely the same size and location of cells;
tight-fitting frame and quality sealant.
The performance of such panels will certainly not cause any complaints. Manufacturers are usually Turkish, Eastern European or well-known Chinese firms.
3. Grad C.
A quality class usually found in used batteries from Western Europe, Japan or the USA, as well as new “no name” products from companies from the Middle Kingdom. A careful visual inspection and performance check of such solar panels reveals:
- a certain amount of small mechanical damage – micro-scratches, edge chips, dents on the frame;
- significant color gradation of the cell surface;
- uneven soldering, typical for manual performance of this operation;
- unstable current-voltage characteristics;
- reduced, in comparison with the passport, efficiency.
Despite the 20-40% and lower cost than the products of the higher classes, it is not recommended to purchase these panels.
4. Grad D.
The fourth category is a product with an absolutely unpredictable remaining service life. On examination, it is easy to find:
- multiple defects;
- uneven sealing of current busbar contacts;
- not strictly equal to 90 ° angle of joint of the frame parts;
- unevenly applied, dried and / or cracked sealant;
- peeling off the film.
Recommended for purchase only for spare parts.
How to visually check a solar panel for performance
A visual inspection in combination with an analysis of the origin of the panels and their quality will reveal almost all possible damage to the modules, with the exception of intrastructural ones.
1. Cells. We visually inspect their size and location in the module. None of the cells should differ from the rest in size. Thin strips separating the rows of elements and each of them from each other must also be absolutely the same width. If these conditions are met, the cutting and stacking was carried out on a fully robotic line, and the quality of the assembly is beyond doubt.
2. Soldering contacts. Similar considerations are valid for the places where contacts are soldered to busbars. The robot cannot solder each element differently. A person, even who is a master of his craft, will not get such monotony.
3. Frames. If you carefully inspect and check the solar panel, such problem areas are easy to find. Among the most common are:
- the angle of the joint of the perpendicular battens, clearly unequal to 90 degrees;
- minor dents or scratches on the case;
- microscopic slits or displacements;
- an uneven layer of sealant between the frames and the backs of the panels;
- the presence of cracks or missing areas in the sealant.
Any of the above reasons is a gross violation of the rule of ideal tightness of the module. Ignoring such errors will necessarily lead to moisture penetration and rapid cell degradation. In the best case, the performance of the system will decrease 2-3 times over just a few years. In the worst case, as a result of a short circuit, you will lose money invested in the system.
Why is it so important to carry out such a check? Because almost half of the panels from the Middle Kingdom from little-known manufacturers are not assembled by robots, but by Chinese guys with a soldering iron and a bottle of silicone in their hands.
Conclusions from testing solar panels for performance
In most cases, self-checking photovoltaic panels allows you to assess the level of their future performance with a high degree of accuracy.
Conclusions from testing solar panels for performance
In most cases, self-checking photovoltaic panels allows you to assess the level of their future performance with a high degree of accuracy.
The most dangerous defects are:
- signs of leakage;
- not robotic, but a manual method of stacking and soldering elements;
- uneven color shade, indicating the loss of structural uniformity by elements;
- mechanical deformation of the frame and any visually noticeable damage to the protective glass or film.
Literally in a year, the performance of such a solar battery can drop to 25-30% of the passport indicators, and in a few years it can be completely out of order.