Are you wondering about setting up an off-grid solar power system by yourself? Maybe, you would like to know about all the components related to the solar power system, how they work and how to connect them to power up your off-grid home.
Don’t worry whether you are a complete beginner or someone who knows a bit about here and there, in this article, I am going to cover All the things you need in order to build a complete DIY off-grid solar system.
At the beginning of the article, I will explain some basic things about electricity. Then we will be going to discuss the components of the solar power system. And after that, we are going to dive deep into the solar system wiring diagram and solar system design. At this point, you will know how everything works and you will have an understanding of overall things about the power system.
I will try to explain everything in a simple way for you to understand. So, without further ado let’s get started.
Electricity - The fundamentals
Let’s start by knowing what is electricity. Every matter in the world is made out of small atoms and if you divide an atom you will have electrons, protons and neutrons. Electrons are negatively charged (-), protons are positively charged (+) and neutron doesn’t have a charge.
The number of electrons (-) and protons (+) are the same (balanced) in any object or matter. For example, let’s say a matter has 5 electrons and 5 protons. By any means, if I can make a difference between the number, then it is known as a potential difference.
Let’s increase the number of electrons to 7. Then after that whenever it gets connected to any positively charged things, it will transfer the extra 2 electrons to balance itself (the matter). So, this flow of 2 extra electrons will be the electricity.
Maybe you have noticed this positive (+) and negative (-) symbol in the battery or other components and it is coming from this concept. In real life, sometimes when you are opening a door you may feel an electric shock, it’s because your body generated some extra electron (-) and when you touch a metal doorknob the electron transfers through it to the ground. In any case, any matter tries to get rid of the extra electron when it’s connected to the ground. (Ground of the earth is Positively charged by nature)
So, what you can learn from this concept? In a solar power system, we have a battery, right? This battery can store extra electrons generated from the solar panel. Every battery has a capacity of how many extra electrons it can store. After storing the electrons in a battery, we can connect the battery to electronic appliances and these electrons get transferred from the battery towards the appliances and power up them. The appliances will run until all the extra electrons in the battery are transferred or in other terms until the battery charge gets depleted. So, we have to keep charging the battery to store the electrons or maybe we can get a large battery or have battery backup.
Type of Electricity
Let’s go into a bit more advanced concept. it is important to know for our setup, so I cannot skip it.
Until now what I have discussed is direct current also known as DC power. What we get from a battery is DC power. But in our daily life, not all electronic equipment can run on DC power. We need also AC power which is known as alternating current.
What is AC power and why Do we also need AC?
DC has some limitations it has less speed or force of electricity. If Our battery is 12V it means the battery can draw out electrons in 12 voltage. Think of voltage is like a force or pressure. For example, If the speed of the wind rises then we know that the wind is flowing faster. You may see that 20km/h or miles/h in case of wind speed. The same goes here, 12V means the amount of speed the electricity is flowing through.
In the case of AC, in the USA, we use 120V electricity, in the UK it is 230V and in Australia it is 220V. Electronics like iron, drill machine or high-power equipment need high voltage to operate. High voltage is also dangerous. If you are not a professional or expert or don’t know what you are doing it’s better not to mess with AC and it can cause you death.
Another characteristic of AC which makes it different from DC is that it is alternating. In the case of DC, the current flow in one direction. But in AC, the current flows in Both directions. It goes back and forth multiple times per second. In the USA, this alternating value is 60HZ (hertz) means alternating back and forth 60 times per second. In UK and Australia, it is 50HZ.
A few more Basics
Since we have discussed Voltage, let’s talk about current and resistance in short.
In a simple way to understand resistance, we can say resistance is just like obstacles. Imagine, we are walking on a road and the road is not good. it has many stones or obstacles and slowing down our speed. Similarly, when an electron flows through something it can be obstructed which we call resistance. The unit of resistance is the ohm. So, the amount of electron blocked can be represented by this ohm.
Current is the amount of electricity that went through at a certain speed against the resistance. In the equation of current, it represents with “I”. it can be calculated with I = V/R. So, Current = voltage divided by resistance. The unit of current is ampere.
If you want to know the power of any system then you can calculate with the equation, power = voltage x current. the unit of power is watt. these equations are required for calculating the power you need in your house.
Whew! That’s a lot of theory. I tried to simplify as much as possible. This is not everything and there are tons to know about it. But we don’t need to know all of them right now. In the upcoming sections let’s discuss all the components we are going to need in a solar panel system then we will do the solar power system design for our off-grid house. Let’s continue.
Components of Solar power system
Here we will discuss the components we need for our system.
Solar Panel
The main part of the Solar power system is the solar panel which will convert the solar energy to electricity. It comes in different sizes. Solar Panel has photovoltaic cells or PV cell.
Normally plant has the cells to convert the photon (light of the sun) to make food for themselves. But here in the solar panel, we have photovoltaic cells which will convert the photon or light to usable electricity.
Each solar panel has different power and current rating. The solar panel with a Higher watt rating will produce more electricity. Also, you can use multiple panels to increase the rating.
Battery
The battery is the heart of the solar power system. It stores the Electricity came from solar panels and supplies to the electronic appliances. There are various types of batteries that are used to store solar energy and the most common one is the Lithium Ion battery.
A battery is rated in Ampere hour or Ah. If a battery has a capacity of 100Ah then it can run 100 watts of load for one hour. The load is the number of appliances you are powering on with the battery. You can see the number of watts written on the body of the electronic appliances that you use. So, the higher the number of Ah the higher the storage capacity of the battery.
Solar Charge controller
As the name says, the solar charge controller controls the power coming from the solar panel, it controls the battery charge. It also enables the control between battery and inverter (will talk about it soon). Optionally it can also control loads. Solar charge controller’s options and features vary by manufacturer.
Solar Inverter
As we have discussed in the previous section the battery gives Us the DC power supply. But in order to get AC power, we convert the DC to AC by an Inverter. If the inverter says 12v Inverter then it can convert 12v DC to AC.
Depending on the country you live in you may need to know how much AC Voltage you need for your appliances. It is also written on electronic appliances. You may be needed to have a 12v DC to 110V ac inverter if you are living in the USA. I have already mentioned this in the type of electricity section. The inverter has rating which is the amount of load in watts that can hold up to at a time. You should discuss the manufacturer for this.
Circuit Breaker
A circuit breaker is a protective device. It is a type of switch and whenever extra current flow through it triggers and saves the whole system from getting ruined. Different circuit breaker has a different rating. Using a circuit breaker will help you to prevent any accident that may occur. It is best to use it at every point of a circuit where it is crucial.
Off grid Solar System Wiring Diagram
Solar System Wiring Diagram will give you the overall idea of using the components in your power system. The wiring diagram may be different for the different scenarios but the core concept is the same. Here I am going to show you the basic wiring diagram and solar system design for your off-grid house where the output will be in AC.
Using More Solar Panels in your power system
You may be wondering how to connect more solar panels. You can Connect Multiple solar panels to increase power generation. There are two types of connection. One is a series connection and another one is parallel connection. If you connect all the solar panels in series then the voltage of the panels will increase in total but the amount of current will remain the same as before. On the other hand, using parallel connection will increase the current and voltage will remain the same.
Depending on the situation you may need to series or parallel or hybrid connection.
The pros of parallel connection is that, if one of the panels get damaged or malfunction other will work and generate power. But on the other hand, in a series connection, if one of the solar panels malfunctions then the entire circuit will stop working and will not generate any power.
Solar power is one of the most popular renewable energy sources. As the world is running out of fossil fuels, the price is increasing tremendously. Going to a clean energy source like solar energy will not only provide us economic benefits but also going to reduce our carbon footprint on the earth. I believe solar energy is the future and best for off grid power solution.
