The electrical performance parameters of PV modules include open-circuit voltage (Voc), short-circuit current (Isc), operating voltage (Um), operating current (Im) and maximum output power (Pm).
1) When the positive and negative electrodes of modules are short-circuited and U=0, the current will be the short-circuit current. When the positive and negative electrodes of modules are not connected to loads. The voltage between the positive and negative electrodes of modules will be the open-circuit voltage.
2) The maximum output power depends on the solar irradiance, spectral distribution, gradual operating temperature and load size and is generally tested under standard test conditions (STC: AM1.5 spectrum, incident irradiation intensity of 1000W/m2, and module temperature at 25 °C)
3) Operating voltage is the voltage corresponding to the maximum power point, and operating current is the current corresponding to the maximum power point. 

The open-circuit voltage of different types of PV modules differs due to the number of cells and the connection method in the modules, which is about 30V~60V. Modules are not provided with separate electric switches and can generate voltage under light conditions.

Modules should be cleaned with suitable solutions and tools by proper methods, and the cleaning may be done by reference to the PV Module Cleaning Manual of Sunway, which can be obtained by contacting the customer service staff of Sunway.

The blocking of a module by the shadows of surrounding objects, fallen leaves, bird droppings and dust will cause the corresponding part of the cell to heat, and the difference between high and low temperatures of the cell reaching 30 °C or above can be considered as the generation of hot spots; The hot spots of the module affect the overall energy output of the string, and long-term hot spots will affect the normal operation performance of the module and even cause a fire and other potential safety hazards.

The electricity produced by the PV module is direct current, and the ambient electromagnetic field is relatively stable and does not emit electromagnetic waves outward, thus no electromagnetic radiation will be produced.

There is a layer of coating film on the surface of the cell, and the process fluctuation during processing leads to the difference in the thickness of the film, which makes the appearance of the cell vary from blue to black. During the module production process, the cells will be sorted to ensure the same color of the cells inside the same module, but there will be color differences between different modules. The color difference is only the appearance difference of the module and has no effect on the power generation performance of the module.

The difference between mono module and poly module is that the cells are different. Mono cell and poly cell have the same operating principle but different manufacturing processes and appearances. Mono cell has arc chamfers, and poly cell is a complete rectangle.