How To Read Solar Panel Specifications @

In Engineering this is one of the most important role which is reading the specification chart of any electrical apparatus. Today we are going to learn how to read a Solar Panel Data Sheet. Alhamdulillah.

Like every-other catalogues there are some keywords everyone should understand before they read any catalogue page for selecting any device.

To understand a Solar Panel Catalogue or Data Sheet one must know about Voc, Isc, Pax, Vmax, Imax at STC or Nominal case.

STC : This stands for Standard Temperature Condition. This is the condition for every solar panel get tested with. This is equal to 25℃ , 1.5 atmospheric density , 1000watt /square meter light intensity and sun’s angle directly perpendicular to the solar panel at 500 feet above the sea level.

NOCT : This stands for Normal Operating Cell Temperature. This is more practical data comparing with STC as STC is standards but it always close to the STC.

Voc : This stands for Open Circuit Voltage of the Solar Panels. This is  no load condition for solar panels when a multi-meter place  across the positive and the negative terminals of  a solar panel you get Voc.This is a very important number for creating series of solar panels  for charge controllers or inverter as it is the maximum voltage a solar panel can creates.


Isc : This stands for Short Circuit Currents of a  Solar Panel.This is the current rating when the output of a solar panel is short i.e positive and negative of a solar panel is connected directly without any load presents.This is the highest current a solar panel can provide.

Pmax : This means Maximum Power Point.This is the best power output you can expect from a solar panel. This is the power wattage which MPPT Charge Conroller tries to get and keep it. Pmax=Vmpp x Impp where Vmpp is the voltage at maximum power output and Impp is the current at maximum power output.

I-V Curves of Solar Panel : 

Edyeazul property

The picture  above is the I-V Curve of a solar panel where you can see multiple curves are placed on it but they are identical as curves but has different values.You can see in the above picture there is a  point where power starts to lowering down, this is call MPP (Maximum Power Point ), this is the maximum power a solar panel can provide. At this point you will find two more values one is Vmpp(Maximum power pint  Voltage) and Impp(Maximum power pint  Current.There are other two values you can find from this I-V curve i) Voc (Open Ciruit Voltage ) where solar panel current equals to zero ii)Isc (Short Circuit Current) where voltage equals to zero.

 Reading a Catalogue : 

Above the Picture you can see a catalogue of variety solar panels at first column you find model number of the panels, Next is Maximum Power ratings of solar panels (Pm) , as an example SD-HMB-18-20 shows 18W of maximum power (Mpp) which means this solar panel can give you maximum 18W, Open Ciruit Voltage 23.7V ( This is the no load voltage)  , Short Circuit Current is 0.98A(This is the short circuit current) ,Voltage at Mpp is 19.8V(This is the voltage when you get 18W) and Current at Mpp is 0.91A(This is the current when you get 18W), cell efficiency  20.30 % and others are just weight and dimensions. 

All of this readings are important when you classify any project,so keep in mind the terms because you will need it.

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