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 : 

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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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A Brief Description On Home Solar System Costing

Benjamin is not for sale

Matter  of fact is that everyone wants to earn money but we forget that if we know how to save it before we lost it then your pocket is pretty much the best place you will want to touch.

To save money from Solar Technology, first of all you need to build a Solar System in your house. And to do that you need money at the beginning but you should be careful in few things. Let me list for you....

• There are few things that will be costly for you like Solar Panel, Battery, Inverter and some other things which are you can find in moderate prices like charge controller, cables , and installers. But this is only the equipment cost if you are installing from a company or dealer then there will be service cost too, so keep in mind about all the costs.
• The Solar Panel Cost actually depends on the load, the higher the load the higher the cost. You can use this tool to figure your Solar System Size SolarSizerCalculator.
• Solar Panel Cost are assigned with per watt which means if you need solar panel 100Watt and market price of that brand is 70BDT/Watt then you have to pay 7000BDT for 100Watt Solar Panel. Solar The simple rule is (BDT/Watt x Total Watt) which give you total panel cost. The price will vary about 10~20BDT/Watt depends on Brand or the Panel Type (Mono/Poly/Thin).
• Now let talk about the Battery Cost which is the most crucial and costly product of all but before that you need to know how to choose a Battery, please follow this link Battery Info (Please Read all posts). Please use this tool for your Battery Selection SolarSizerCalculator.
• Battery Cost also vary with the Brand to brand, you need to research your market for that. This cost vary from (8000BDT ~30000BDT) depending on Brand and its Ampere-Hour (AH) rating. In market you pay money for batteries based on its Ah (Ampere-Hour) rating, so calculate it before you go to dealers, please use this SolarSizerCalculator.
• Next is Inverter which is also costly but for house hold system it will come around at most 10000BDT~15000BDT but for certain case this could exceed to 30000BDT depending on its functionalities and power handling capacity. In market this product is sold on VA (volt-ampere) rating, higher the VA rating higher the price.
• Charge Controllers are the next thing you need to install with your Solar Home System. For normal Solar Home System this will be pretty cheap, you can get it at most 4000BDT for the best brand but it varies it prices between 1500~4000BDT depending on it Ampere rating and brands. In market Charge Controller are sold with its Ampere values like 5A, 10A or 20A. But all these information is for only Solar Home System which is below 20A Current ratings.
• Now what left is Cables, Connectors, Switches & Mounting Equipment cost? Cables cost are measured by its length,  so if your system is dealing with higher current like  20A or above then it will cost you more  but actually  cable cost entirely depends on the location and the system connection. If your system is zigzag or very complicated then cost can be higher, but you should counsel with engineer who monitoring these. Connectors are cheap as well as switches but again also if the system is big the price will be high, so can’t say for sure. These can only be done with experience and observation. And last is the solar mounting cost which is very much location and system dependent. These can be on the roof or on the ground but prices depend on how many solar panels are needed and what type installation is required. It could be pole based or railing based or you can make it your own using some support but depends on the system, so it needs observation. The entire cables, connectors, switches or mounting equipment’s can cost you like 8000~15000BDT together, so talk with the engineer.
• The last thing is the installation cost if you are not doing it your own or you are hiring an engineer or a builder for the installation then you has to pay them their service costs.

So keep in mind when you are trying to build your own solar system because this can be the best thing you can do for saving money for a long time which is an amazing decision.

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