This page shows you step-by-step how to build your own solar energy system. It will explain in text and also show you instruction videos on how to do the things in the right order and in the right way.
Introduction
Solar photovoltaic systems are renewable energy providers system. They are installed in both grid-connected and off-grid houses. In grid-connected systems, many install solar power to try and save on energy cost from the utility company.
It is advised that to get most of the solar energy and still want to install a less costly system, please select the appliances with the lowest power ratings.
And if possible unless you have the money to install a huge system, avoid some of the power guzzlers such as instant showers, house heaters, air conditioners etc.
Electrical appliances
In our case we will build up a system that will power a house with the following electrical appliances:
- Television set
- TV set bot
- Laptop
- Phone charger
- Radio
- Light bulbs
Next step after noting all the appliances that will depend on your system power, you calculate in watt-hours the power consumption of each appliance on daily basis. This is done by estimating the number of hours each appliance is used. I.e. mostly a television set is used mostly in the evening and morning.
Let’s say in the evening you use your television set from 4 pm to 12 pm and in the morning you use it from 6 am to 12 am. In total, you use your television for 8 hours in the evening and 6 hours in the morning which adds up to 14 hours daily.
To get the consumption in watt-hours you multiply the number of hours with the television power rating.
I.e. 14 (hours used daily) x 80 watts (power rating) = 1120 watt-hours.
Appliances power consumption in watt-hours (diagram below)
Daily power consumption
To find the house consumption daily you add all the appliances consumption. That is 1120+630+80+500+60+300= 2690 watt-hours (the amount of energy the system should supply daily).
Due to system losses, we multiply with the loss factor (1.3) of the system to make it more stable.
7490×1.3=3497 watt-hours.
To work with round figures we round off this to 4,000watt hours is the energy our system should be able to produce on daily basis. By rounding off we make the system even MORE stable.
Sizing the solar components
1: Solar Panels
Calculating the size of the solar panel (solar panel rating)
Solar panels are available in different sizes, but first, we have to know the energy in watt peak installation.
For countries in Europe, the generation factor of solar panels is 2.98.
We divide the total daily energy with the generation factor to get our solar panel size rating.
4,000 watt-hours/2.98= 1,343 watt peak (size of solar panel needed)
Since we can’t find a solar panel of this size we use the size available and make an array of several of them to total up to the output needed (1343 watt peak)
I use this above solar panel from Amazon as an example, its rating is 250 watts and I decided to use it.
To find how many are needed for the system we divide the total solar panel size with the available size.
1343 watt peak (array size)/250wattspeak= 5.37 panels and since we can’t have a fraction of a solar panel, we round off to 6 panels.
2: Inverter (Determining the inverter size)
The importance of the inverter in the system is converting the dc current to a current which is conducive to most of the home appliances. The inverter should have the same voltage as the batteries. The inverter size should be the total number of appliances rating in watts and should never be lower.
In fact, the inverter size should be 20% more than the total watts of the appliances. In our case, our inverter size is 258 watts and should be increased by 20-30%.
(30/100 x258)+258= 335 watts is the size of the inverter needed
After finding the size needed you the source for the inverter in from the distributors and manufacturers. For our case, we will source from Amazon.
After sourcing from Amazon I found the above to be suitable, mostly because it is a pure sine wave type of inverter. And also because it holds more loads than our system yet it is being sold at a good price. It only goes for $30.
3: Battery
For systems which are not tied to the grid, they need some storage for the energy generated by the system. Batteries are the best components for the storage.
We need to calculate and install the battery size that can hold enough energy for the night and during the days of autonomy. Days of autonomy are those days that are cloudy and rainy when the solar panels generate minimum or even no energy.
(Sizing our battery bank)
i) We need to get the total number of energy consumed by the appliances per day and divide with the battery losses factor (0.85).
2690 watt-hours /0.85= 3164.7 watt-hours
ii) Then we divide the obtained figure above by the battery depth of discharge (0.6).
3164.7watt hours/0.6= 5274 watt hours
The above battery was available on Amazon. It is an Absorbent Glass Mat (AGM) deep cycle battery. The main advantages of deep cycle batteries are:
- They are sealed and very easy to transport
- They are never topped up with water
- They are easily mounted on places such as a car, battery housing of a solar system, etc.
iii) Now we need to find how many batteries are needed for our system. But first, we need to know the size of our battery bank. 5274 watt hours/12v (nominal voltage)
iv)
To get the size of our battery bank, we divide the energy consumption of the system by the battery nominal voltage. battery voltage) =439.5 Ampere hours.
439.5 Ampere-hours is the size of the battery bank needed for our system on daily basis.
v) Adding the days of autonomy is optional. It is only increasing the size of the battery bank by the days you estimate your area can go without sunshine.
vi) To get how many batteries are needed we divide our battery bank size with the size of battery available.
439.5 Ampere hours/200 Ampere hours=2.1975 since there is no a fraction of a battery we round off our figure to 3.
So we need 3-200 Ampere hour batteries for our system.
4: Solar charge controller
The solar charge controller is rated against voltage and current. One should select the best suitable charge controller for the battery and solar panels and the source of the type that is right according to the application.
For our case since we want a less costly one, we will go for series charge controller. The size will depend on our solar panels configuration and voltage.
Typically the size of the solar charge controller is found by multiplying the solar panel short-circuit current with the 1.3(energy losses in the controller)and the number of solar panels to be installed in series connection.
Our solar panels short circuit current is 9.09A
9.09A x 1.3 x 6=70.9A and as usual we round of our figure to 80A will be the size of our solar charge controller.
The next step is to source for our solar charge controller from Amazon. And I found the below solar charge controller ideal for my solar system:
The connection of solar components above
we found out the sizes of the components needed for our solar energy system to supply the appliances with electricity.
We also sourced different manufacturers from Amazon for best components that suites our needs.
And came up with the below Components:
The above are the components, their ratings and their nominal voltages.
The next step is to install and connect your component which is the trickiest part in the installation of your system.
Ok, let´s connect and install (step-by-step guide)
Here I will try explaining in a lay man’s language the best and easiest way to install your components and how to connect each component to another step by step and the type and size of cables you should use.
Also, it is good to not that connection of a solar component depends on the nominal voltage of the component that comes before it in the circuit, the ie connection of solar panels will depend on solar charge controllers nominal voltage.
We will start our connection from the solar panels to the loads (electrical appliances).
Step 1: Solar panels connection
First, we need to determine the type and size of cables to use.
The type of cable to use is the same cable and that comes connected to our solar panels for array interconnection.
But you will need to buy extension cables to run from the solar panel array to the solar charge controller.
You will need to determine the installation area of your array and the installation area of the solar charge controller and then buy cables equivalent to that distant.
For the interconnection of the solar panels to form an array, there are two ways to do that, you can connect either in parallel or series.
For our array, it should have an output 24v which is the nominal voltage of our solar charge controller and the solar panel.
If you connect solar panels in parallel they tend to add up current of each panel together. I.e. if you have 3 12v solar panels with 9A each and they are connected in parallel, the total output current will be 9A x3= 18 A and the output voltage will be equivalent to the voltage of one solar panel.
If they were connected in series, the output current would be equivalent to that of one solar panel and the output voltage would add up 12v x3=36v. In series, voltage adds up.
Since the solar charge controller nominal voltage is 12/24 volts and 80A current, we are going to connect the solar panel in parallel form, to get our array outputs as; voltage as 24v and current as 55A.
But remember we multiplied 55A x1.3 (charge controller losses) to get 71.5A; then we rounded off the figure to 80A. That how we got the size of the solar charge controller.
(Figure above shows connection of our solar panel Array)
After the interconnection, make sure to use a 16mm single core cable size to handle the 55A load from the solar array output to the solar charge controller.
For the mounting of the solar array, you can make a structure and mount them on the roof facing south.
Why south? This is because Sweden is north of the equator which is the suns path.
For more illustration watch video below:
Step 2: Solar charge controller connection
From the solar panel connection, the current flows into the solar charge controller. Our solar charge controller has a nominal voltage of 24v as its rating and from solar array output.
As the name suggests solar charge controller controls the amount of energy flowing into its output and input. For instance, it regulates current from flowing back to the solar panels and also charges the solar batteries.
The solar charge controller is not complex to connect, it has inputs and outputs clear shown all you have to do is connect solar panel input where it is shown and battery output where it is shown and all about solar charge controller will be done. But most solar charge controllers have an extra output apart from battery output that is meant for dc loads.
(the figure above shows various input and output of the solar charge controller)
Step 3: Battery connection
Battery connections are just like the solar panel’s series and parallel.
Our batteries have a nominal voltage of 12v each. And our solar charge controller has a nominal voltage of 24v; we will need to figure out how to connect our 6 12v batteries so that together they can give a 24v output.
The configuration of the battery to use is we connect three batteries in parallel and the other three batteries in parallel so that each pair has an output of 12 volts.
Then we connect the two pairs in series so that the voltage adds up to 24volts which is now the system voltage at this point.
Watch the following video for more illustration:
Step 4: Inverter connection
For the inverter, the connection is also not complex. You only have to connect your inverter input cables to the output of the battery bank.
After doing that the inverter will convert the 24v dc current into 230v ac current which is suitable for your loads (home appliances).
The output of the inverter is treated as the utility current; there are no special cases it is distributed to the lights and sockets normally through a consumer unit with the correct circuit breakers just as in utility power distribution.
Watch the following video for more illustration:
Solar panels and battery bank connections are the ones which are bit trick connect because of the issue to do with parallel and series connections of voltage and current.
The procedures above should work very effectively. Of course, you should have electrical knowledge to fully understand the above procedures. Since we have known how to connect our system and connection don’t change, we will go further and see the different budgets of the solar energy system.
This will vary because of the use of different electrical appliances and be using them minimally daily.
Solar energy systems budgets
Solar energy systems have different budgets. Some are way too much costly and very expensive. This arises when it’s time to purchase your solar energy components after sizing your solar energy system. These different budgets are also influenced by various factors and points to consider when installing/sizing for your system.
Factors influencing different sizes/budgets of solar energy systems
There are key points and issue which cause a difference in solar energy systems sizes and budgets. Below are main issues and points that cause the variation:
Generation factor of solar panels
Same Solar panels have different generation factor in different climates (depending on geographical locations of the area). For instance, in Thailand, the generation factor is 3.43 and in countries in Europe, the factor is 2.93.the factor is used to calculate the total watt-peak rating for your solar system.
Areas with high generation factor such as Africa receive more sun hour than those with a lower generation factor. So the high the generation factor the less watt-peak of your solar system. And that means the solar panel size will be reduced and thus the cost of solar panels also reduces.
A generation factor for solar panels is not a characteristic owned by the solar panel. Generation factor arises when you think of how much sunshine is in a given area. And for how many hours the place receives full sunlight.
Depending on the place you live or the place you would wish to install your system you would first have to know the solar insolation of your geographical location… and the ration you get is the one we referring to as the generation factor (best referred to as the average sun hours received in a day).
So regardless of where you are reading this article from and you want to follow the steps to install your system, to move on, first you have to get the average number of sun hours available in your area and use it as your generation factor.
From America to Australia, Africa to Europé and all the other parts of the World solar panels will work differently just because of that one factor – generation factor (solar insolation or daily sun hours)
Usage of solar components
Different households would use electricity at different rates. The number of hours you use your electrical appliance will cause a difference in daily watt-hours consumption. Thus you need to adjust your appliances usage to a point where the system you can afford can generate the energy needed.
Types of appliance
Different electrical appliances have different electrical consumption rates. For instance, a microwave consumes ten times more than an LED television set. You would need to use appliances that suit your solar energy system.
Type of solar components used
Some people would prefer to use a solar charge controller that has the capability of tracking the sun which is way more expensive than a typical solar charge controller. Depending on your budget you are supposed to choose the components to use considering your budget.
Type of current
There are two types of current, direct and alternating current. If you choose to use direct current directly from the battery or from the solar panels, the budget would lower down than the system using alternating current since an inverter must be present which a direct current doesn’t need.
Type of your solar system
Is your system grid tied or off the grid? How much did it cost you? Those systems which are grid-tied are less cheap because they don’t need to buy solar batteries since the grid act as their storage.
How to reduce your solar energy system cost
Above we have seen the different factors and points which influence different costs and budgets of solar energy. Below we are going to look at how to reduce your solar energy system cost.
Use your appliances minimally daily
The less number of hours you use your appliances the huge the difference of your solar energy system and this means you will need small size of solar Components.
Use of solar-friendly appliances
Use of solar-friendly appliances such as LED bulbs and solar refrigerators lowers you system cost by a significant amount of dollars.
Use of direct current
Though it is not that common, using dc current eliminates the inverter budgets.
Connecting your system to the grid. It can be worth to mention that this is the most common way to reduce your solar energy cost or pay back the cost of your system.
This is because you feed your energy to the utility grid rather than in the batteries. More so if you don’t use all the energy you feed to the grid, the utility company pays you for the remaining energy. This is also regarded as the investment aspect of solar energy.
Simplified sizing for your solar system
Before you continue to sizing for your solar components sizes (inverter, solar panel, solar charge controller, battery bank and cable sizes) you will need to know how many electrical appliances your system is going to power and for how long in a daily basis.
Usually, the power ratings of the appliance are written on a sticker attached to it. After doing it you will get your daily household power consumption in watt-hours.
Then follow the simple steps below to size for your solar Components:
Solar panel
With your daily consumption(watt-hours)
Watt hours x generation factor= watt-peak of solar panels needed
Watt-peak/watts of solar panel available=number of solar panels available needed for your system
Inverter
With all appliances ratings(watts) add all the rating together and then increment the total by 30% you will get the size of inverter needed by your system
Battery bank
With your daily consumption(watt-hours)
Watt-hours /0.85(battery losses) = watt hours
Watt-hour (after multiplying with battery losses)/0.6 (depth of discharge) =watt hours
Watt-hour (after multiplying with depth of discharge)/battery voltage (of battery available) =battery bank size (AH)
Battery bank size (AH)/size of battery available (AH) = number of batteries available needed for your solar system
Solar charge controller
Read the short circuit current (Isc) of your solar panels.
Isc x number of solar panels needed =Isc for solar panel array
Isc (solar panel array) x 1.3(solar charge controller losses) = size of solar charge controller in Amperes (A)
For cables and connectors, you can check different types of cables and their amperage rating online or charts provided by cables manufacturing companies
Solar energy systems budgets
As we discussed different budgets are influenced by different generation factor of solar panel, hours of use and number of electrical appliances. This way we are going to look at different budgets for a household with almost all the basic electrical appliances.
We will assume the household is in Europe so our generation factor will be 2.98. This way we will size for different components prices in Amazon.
For every given household we will look at its solar energy system budgets in categories that can fit into pretty much anyone’s budget.
Simply pick and click your desired budget button below
