To get the best out of Solar panels, an understanding of the technical specifications is required as these will determine the actual performance of the solar panels when put to use. Commercially available solar panels will typically have the following specifications on their name plate:
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Typical Technical Specifications on the Nameplate of a Solar
Panel
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1
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Irradiance in W/m2
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2
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Cell temperature
in degree Celsius or Fahrenheit
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3
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Maximum power derivable from the solar panel, Pmax.
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4
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Maximum Voltage
generated by the Solar Panel, Vmax
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5
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Maximum output current from the Solar Panel, Imax
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6
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Open circuit
voltage of the Solar Panel, Voc
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7
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Short Circuit current of the Solar Panel, Isc
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There are other technical parameters commonly found on the name plate of solar panels such as panel dimension and weight. Some of the technical parameters indicated in the table above are shown below in the I-V curve of a solar panel:
Solar Irradiance
The solar irradiance is the power per unit area received from the sun by the solar PV module. It is measured in Watts per square meters (W/m2). Most solar panels are tested under STC at 25 degrees Celsius and 1.5 atmospheres. Under STC, the irradiance of a solar panel is 1000W/m2.
Cell temperature
This is the temperature of the solar cells under STC. As temperature increases above the STC value of 25 degrees, the efficiency and voltage of a solar panel tends to decrease.
Pmax (Maximum Power)
This is the maximum power derivable from the solar panels under STC. For any given solar panel, Pmax is given by:
Pmax = Imax * Vmax
In the I-V curve shown above for a typical solar panel or cell, there is a maximum power point labelled Vmp and Imp and is the operating point at which the maximum output will be produced by the module at operating conditions indicated for that curve.
Vmax (Maximum voltage)
This is the maximum voltage generated by the solar panel under STC
Imax (Maximum Current)
This is the maximum output current of the solar panel under load condition test at STC.
Voc (Open Circuit Voltage)
The open circuit voltage of a solar panel, Voc, is the maximum voltage achieved when no current is being drawn from the module. Since no current is flowing, the module experiences maximum electrical potential.
Isc (Short Circuit Current)
The short circuit current of a solar panel, Isc, is the maximum current output that can be reached by the module under the conditions of a circuit with zero resistance or a short circuit.
