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.
MC4 connector
MC4 connectors are used for connecting solar panels to each other and for crimping the ends of power cables. Such connectors have a sealed waterproof design, suitable for outdoor use.
MC4 connectors are available in female and male versions. They provide long-term stability of solar panels and resistance to climatic influences.
Support foot
A device that allows you to install the solar panel at an angle to the horizontal, so that the sun's rays fall on it at an angle of about 90 °. In stationary solar panels, the
support footboard is usually attached to the frame; in portable models, it is a separate cover. If the panel is sewn directly into the case, folding steps can be provided in such solar batteries.
Suspension system
Possibility of mounting a solar battery in a suspended state. As a rule,
the suspension structure is implemented by means of holes in the panel for threading laces or installing carabiners.
