Solar Household System

Before I talk about solar household system, let me give you a brief concept on solar technology. Let’s begin with the first question what it is. This is the technology where electricity generated from solar energy Using Photo voltaic Panels. There are two basic types of System in solar technology i) On Grid ii) Off Grid, System can be combined as well which is called Hybrid System.

There are basically few fundamental parts in Solar Electricity system; whether it is  on grid or off grid , i) Solar Panels ii) Cables iii) Connectors iv) Combiners v) Batteries  vi) Charge Controllers  Later we need Inverters in case system is AC, but in modern Solar technology systems are more complicated than simple but not impossible, why I am saying it because in every household system is different than the other, a system can have both AC and DC appliances together, and we have to careful about the cost of the installation too.   

Picture B

A solar home system can be very costly it you don't have good idea on it. Everything in solar system is expensive due to longevity of its service, you will find everything in  solar product has warranty 1~3 years. 

Before you install a solar home system calculate your own house power needs and what type of solar home system you want, what type of electrical devices are there in your house, are those all AC or DC.If you are unaware or confuse about it then please see Electrical Machine & House ,

and then calculate total power according to http://edyeazul.blogspot.com/p/blog-page_22.html ,

and then you consult with a engineer or you also can contact with me ,you can mail me your home picture or you can mail me the number of electrical apparatus are  in your house , I will tell you exactly what you need to know.

But in general; you have to buy few product which is must,

•                         A) Solar Panel ( 30W~250W)
•                         C) Solar Battery ( 50Ah~130 Ah)
•                         B) Charge Controller ( 5A~20A)
•                         D)  Inverters (500W~1000W)
•                         E & F ) Cables & Connectors 

If you really anxious about the cost then it is okay that proves you are human, but you can start with very simpler and cheaper solar home system at first for tryout , just install solar for only 5  DC LED lights which can cover your entire house that  may cost you like 15000~ 20000Tk at most. In solar home system the most expensive thing is the battery which is 50% cost of the entire solar system , but if you have any cheap source of battery than you can reduce the cost but make sure that battery is 12V/24V or not depreciated too much i.e it gives smooth dc current. 

Building a Simple Solar home System (100W)

Let  us consider a system which needs 100W of solar power system, Lets get started.

Things U can run i) 5 Lights ii) 2 Lights + 1 Fan iii) Only Computer iv) Devices that under 71~75W

If your System is whole DC than you don't need Inverters but if it is AC or DC+AC then you need Inverters.

Things you need to  have  i) Solar Panel 100W{Cost ~ (52~70)Tk/Watt)}
                                       ii) Charge Controller ( 1500~2500)Tk
                                       iii) Battery  120Ah { Cost (12000~16000)Tk)
                                       iv) Inverters  500W   {8000~10000 Tk}
                                       v) Cable & Connectors & Stands (Cost ( around 5000 Tk)

The Cost is given above  is at maximum rate, price could be less than that and it depends on the market , so don't freak out just research the market a bit.

This is not allowed

Make sure every cell of the Panels are in sun.

Then go for the second step which is placing the solar panel on Stands or Pole.

Before solar panel placement we need to know few more things one of them is optimal tilt, question is what is it.Optimal tilt is an angle which direct the solar panel inclination angle. This is the angle in which solar panel can capture the maximum power from the sun. But optimal tilt gets changed with the season, it categorizes into three section i)Summer ii) Spring iii) Winter.   

 

In the summer sun is at its higher position and in winter sun is at its lowest position , the optimal angle change due to this irregular distance of the sun from the earth, to get maximum power from the sun we have to adjust the tilt  of the solar panel. But in general solar panel is placed with an angle close to the latitude of the country compare to the horizontal. 

For Bangladesh this is 23  degree. The optimal angle for other countries vary with place to place, the picture given below is a demonstration of the optimal angle throughout the world.

So , place your solar panel 100W at the south on the roof or anywhere the light is available all the time and make sure no shade on the solar panel.

Place Panel like the picture below; 

Optimal Angle for Bangladesh

Direction of the Solar Panel should be facing the South, no matter which region of Bangladesh do you live in face your panel south.........

Make sure the optimal angle a.k.a tilt is closer to the country Latitude ....

Remember 
you are using a fixed tilt system which maximum will capture 71~72% of the Solar power, if you want 100% use 2- axis Tracker , but in this project I will show you only the fixed tilt.

Next step is connecting Wires and connectors with the other parts of the solar system as well as loads. But before connection you need to which type of solar cable you are going to use. In practical case there is no fixed cable for every solar panel, choosing cable depends on the rating of solar power, specially the current.

In school we all read that conductor conductivity depends on its length and cross sectional area , and the more the cross section area the conductor the more is the capacity of current it can conduct.

for the case of 100W 12V Solar power system current is (100/12) = 8.33..A currents....
When you are going to choose for the cable for your project, you will buy cables that can bear that currents otherwise it will burn..Please check this link Solar Cables


you need to understand cable catalogue 

Let assume the 2x1.0 re cable for this project, it can bear 13A >8.33A....Alhamdulillah....
Now follow this link for cable connection to MC4 connectors 


http://edyeazul.blogspot.com/2016/12/creating-24v-120w-system-using-solar.html

After connecting the Cables to the Solar Panel , bring the output cable to input of the 10A Charger Controller .....given in Picture B...

Charge controller has Six inputs in general,could be more depends on project, in our case there will be six connection points , two for Solar Panel , two for Batteries and two for DC Loads.....

As the below picture is shown 

As you see in the Picture your 100W 12V Panel output connection  went  into first two points of charge controller and next two joints connected with the 12V 120Ah Battery, and other two joints are connected with the DC loads....

Battery is the most important part of an off grid solar system, before installing a battery check the battery is good and long lasting, it is very expensive material. Before buying make sure your battery compatible with solar panel , don't buy 24V battery for 12V Solar Panel..

Note : buy your battery 40%~60% more energy storing capable compare to what your solar panel can provide per hour, as an example 100W solar panel will provide at fixed tilt 71~75W per hour , To save your battery from depletion of charge you need to keep 40~50% of its total energy. Don’t use 100% of a battery can provide, this will kill your battery in 1~2 years which is not a good idea, your mission is to keep your battery health 8~10 years or more .

There is no fixed equation for battery sizing , but there is a process to calculate it ,
First Calculate Wh of your Solar Panel Can provide per day
 = (Solar Panel power x avg.day light hour )x0.7
(avg.day light hour is different from place to place, for Bangladesh it is 4.5~5 hour ) 
Wiki https://en.wikipedia.org/wiki/Solar_irradiance
For the case of 100W = (100W x 4.5 hour) x 0.7 = 315 Wh/day your panel can give at fixed tilt.

To save this energy you need at least 315Wh Battery , but for the case of depth of discharge, we take 50%
then the Battery we need = 315+ (315x 0.5) = 472.5Wh = 472.5Wh/12V =40Ah ,

Now this 40Ah Battery is design for a Load system which is 70W and running for 4.5 hour uninterrupted,


So that is how you can calculate Battery of a Solar System 

But if you have any AC device like ac bulb, ac fan or computer in this 100W Solar System , then you have to install an inverter.....

Choosing an inverter is simpler than choosing Batteries at least , but choose wisely.

choose 2, 3 times factor of the load capacity, but most of the time you probably can't find exactly what you want then just buy which is closer with your demand, like for a 70W load system inverter should be 150W~200W, but in market it is hardly available, or you have to order it personally,

To avoid this problem buy closer device like 500W , but worth it ,you can install more panel with the same inverter.   

The input of the inverter should come from the batteries , please be careful that your inverter has all kind of protection system like over voltage , short circuit  protection , this is important.

The AC load will be feed from the out put of the Inverter.......Check the voltage and Current are smooth a modified sine wave is coming, which is very important...

Note  :i) use battery connector or crocodile connector in case of charge controller to battery connection

          ii) use a clamp meter for measuring   voltage and currents in the wires....

          iii) use gloves and  hear gear for safety...

I hope you like this post ......Jajakallahu Khairan