How to choose solar panels?
Currently, about 80-90% of solar cells are manufactured in China, it is very likely that even in modules sold as "German", "American" and the like, Chinese solar cells are used. This is not necessary to be afraid of since in the past few years the quality of solar cells produced by large Chinese manufacturers has greatly improved and meets world standards. Another thing is that there are a lot of cheap Chinese modules on the market now made from low-quality solar cells. How to distinguish good modules and elements from cheap ones made from rejected elements?
There are 4 levels of quality solar cells, called "grade" - A, B, C and D. Elements of different classes differ in their microstructure, which, in turn, affects their parameters and durability. What is the difference between solar cells of different quality levels?
Grade A solar cells are of the highest quality. They have no chips, cracks and scratches, which lead to a decrease in the efficiency of energy conversion of sunlight into electricity. They have an ideal appearance, uniformity of crystals, colours, etc. If we put 2 halves of different elements together, then it is impossible to distinguish them from each other. The fill factor of VAChtaky elements more than 0.7.
Grade B solar cells have visual defects and have a lower filling coefficient of the IVC - 0.4-0.7. Their price is usually slightly lower than that of Grade A. These elements “age” faster, and even initially their productivity is lower - this can be seen by making simple calculations and comparing the received power per unit area for modules made of Grade B and Grade elements A.
Grade C solar cells have defects affecting their performance and performance. The energy production of these elements is lower than the elements of Grade A or B.
Grade D solar cells are broken elements, sometimes they are made of low-power modules from scrap, but mostly this stuff goes into the smelter for new silicon. They are simply considered unsuitable for use in modules, which unscrupulous module builders safely use. Elements are chipped, microcracks + may have the same defects as Grade B elements. Such elements buy up, cut, leave the whole parts and from them solder modules.
Grade D modules with microcracks are especially dangerous to use and can lead to the fire. The temperature at the point of microcrack can rise to 300 degrees and higher within 1 minute. Of course, the modules on the glass will not immediately catch fire from such a temperature, and insurance companies in Europe and the USA do not mention instances of a house fire from solar modules, but all the same, it is better not to use modules with microcracks in high voltage systems and high-voltage network inverters.
It is better to consciously buy cheap modules Grade B and join the cohort of "solar energy" than just dream of better modules and postpone the purchase of Solar Batteries! The choice is yours!