Specs (STC)
Standard Test Conditions (STC) are standard test conditions that reflect the operation of a solar panel under ideal conditions. As part of the tests, the weather of a clear sunny day with an air temperature of +25 °C, no wind, solar intensity of 1000 W/m² and an emission spectrum relative to air mass of 1.5 is simulated. The surface of the solar cell must be placed strictly perpendicular to the rays from the celestial body. Note that in real operation of the solar panel, such conditions are extremely rare. However, in general, the characteristics of the STC allow us to evaluate the "passport" parameters of the energy storage device.
Nominal voltage (Vmp)
The voltage reading on the voltmeter during a solar panel test at the nominal power level according to the STC method. This parameter, Vmp, stands for Voltage at Maximum Power and is measured in volts. It helps determine which type of batteries the panel is designed for — either
12 V or
24V.
Nominal power (Imp)
Ammeter reading during solar panel testing under STC conditions. The value of the rated current Imp (Current at Maximum Power) is measured in amperes.
Open-circuit voltage (Voc)
The voltage generated by the solar battery in idle mode, that is, without connecting the load. Behind the abbreviation Voc stands for Voltage Open Circuit.
Short circuit current (Isc)
The current value under the condition of zero voltage (Short Circuit Current).
Efficiency
Percentage of the maximum solar panel power to the incident radiation power produced. The efficiency parameter allows you to determine how efficiently the panel PV module converts solar energy into direct electric current.
Specs (NOCT)
The characteristics of NOCT (Nominal Operating Cell Temperature) reflect more realistic operating conditions for solar panels. Testing according to this method is carried out at a lighting intensity of 800 W/m², an air temperature of +20 °C and a wind speed of 1 m/s. The solar battery is placed at an angle of 45° relative to the incident light rays with a south orientation. The temperature of the panel surface in this case reaches +40 - 45 °С.
Power (Pmax)
The amount of electricity in watts that a solar panel produces in one hour in tests according to the NOCT method. The panel must provide the declared number of watts during normal operation.
Rated voltage (Vmp)
The value on the voltmeter when testing the solar battery at the nominal power level according to the NOCT method. The Vmp parameter is measured in volts. It stands for Voltage at Maximum Power.
