Solar panel parameters are given by the manufacturer under STC (standard test conditions). Under STC, the corresponding solar radiation is equal to 1000W/m2, the operating temperature of the battery is equal to 25 ° C, and Am is equal to 1.5.
The parameters of solar cells are as follows:
ISC, short circuit current. Short circuit current is the maximum current generated by the solar panel, and its unit is ampere (A) or milliampere (mA). The value of short circuit depends on the area of solar panel, solar radiation falling on the solar panel, battery technology, etc. Sometimes the manufacturer gives the current density rather than the current value. The current density is represented by “J”, and the short-circuit current density is represented by “JSC”. The relationship between them can be expressed by the following formula: JSC=ISC/A. For example, the current density of a solar panel at STC is 50 mA/cm2, and the area is 300 cm2. Then the short-circuit current can be determined as follows: ISC=JSC * Area=50 * 300=15000mA=15A
VOC, open circuit voltage. The open circuit voltage is the maximum voltage that the solar panel can generate under open circuit conditions. It is measured in volts (V) or millivolts (mV). The value of VOC depends on the solar panel technology and operating temperature.
PM, peak power. The unit of measurement is usually W. The maximum power represents the maximum power generated by the solar panel under STC. It is measured by Wpeak or simple WP. In addition to STC, solar panels also have PM at different irradiance and operating temperature values. The solar panel can work under different current and voltage combinations. However, it can only generate the maximum power PM under a specific combination of voltage and current, which can be expressed by the following formula: PM=IM × VM 。
Imp, the current at the maximum power point. It refers to the current generated when the solar panel operates at the maximum power point. Its value is always less than the short-circuit current (ISC). It is measured in amperes (A) or milliamperes (mA).
Vmp, the voltage at the maximum power point. It represents the voltage generated when the solar panel works at the maximum power point. It is measured in volts (V) or millivolts (mV).
FF (%), the filling factor, which is expressed in percentage (%). The higher the filling factor, the better the battery. The fill factor is defined as the maximum power generated (at MPP) divided by the product of ISC and VOC. We can see that the fill factor is always less than 1. Because it is difficult to measure the conversion efficiency quickly, the filling factor is usually used instead. It is usually expressed by the following formula: FF=Pm/(Isc × Voc)
, efficiency. The efficiency of the solar panel is defined as the maximum output power (PM) divided by the input power (PIN). It is measured in percentage (%), which indicates that this percentage of input sunlight power is converted into electrical energy. The input power is the power density. Efficiency can be calculated as follows:=PM/(PIN × Area)
The above are some common data in the solar panel specification. If you want to know more about solar panels, please contact us, Huanqi Technology (Shenzhen) Co., Ltd.