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.
Power (Pmax)
The amount of electricity in watts that a solar panel produces in one hour in tests using the STC method. The panel must provide the declared number of watts during normal operation.
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.
USB A
"USB A" is the official name for the classic full-sized USB port.
Such connectors are very popular in computer technology, they are also standardly used in adapter chargers for 230 V household networks and 12 V auto sockets. In solar panels, mainly in a portable form factor,
USB A outputs are widely used for charging gadgets.
— Quantity. The number of full size USB ports in the solar panel design.
- The strength of the current. The maximum current output through the USB A connector to the device being charged. Note that different ports of the solar panels can output different current (for example, 1.5 A and 2.1 A). In this case, the highest current strength is usually indicated.
— Power. The maximum power in watts (W) that the solar panel is capable of delivering to one rechargeable gadget. High output power allows you to speed up the charging process. However, the appropriate power must be supported by the device being charged - otherwise the speed of the process will be limited by the characteristics of the gadget. For models with multiple USB A ports, the maximum power per device can be reached when the other ports are not used.
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.
