I wish I could tell you that solar power system is inexpensive but I’m sorry to burst your bubble, it is expensive.
However, contrary to everyone’s opinion, an objective person can own a solar system and that is why I am here to help you be objective.
Solar is one of the renewable green power sources. In a day, you have nothing less than five (5) hours of sunlight (except on extreme cloudy days) and if properly harnessed, you have yourself an efficient means of power supply.
Owning a solar power system means you have the following items in place:
– CHARGE CONTROLLER
– BATTERY BANK
– SOLAR PANEL
I really do not need to expound on each of the items in order to avoid a long post here. So, you can read up on each item if you want to be a little bit technically sound about it.
Here is what I think you need to know; without a solar panel, you don’t have a solar power system even if you have other items listed above. The solar panel is the medium through which sunlight is absorbed and converted to electricity. The power generated from these panels are DC power and are usually not useful except your electronics/appliances are purely DC (Direct Current).
This is where your inverter comes into play. Its major purpose is to help convert (invert) the DC power from the solar to AC (Alternating Current) power that will be useful for you to power your appliances.
But to what use is the solar, if at night you can’t enjoy the power? Or to what use is it when you can store some of its power when the sun is at its peak and enjoy it when the sun is down?
Having a battery bank put all these to rest. Your batteries store up the DC power from the solar power so that anytime the sun is down and you need power, you can easily retrieve it and convert to AC through your inverter. The larger your battery bank, the longer you have constant steady power.
However, harnessing the power from the solar panel directly to your battery will damage your battery in no time. To prevent this, the charge controller helps to controlling the rate at which the battery store up the charge.
The charge controller, is the least expensive item in a solar power system.
I believe you now know what makes up a solar power system.
However, you can’t just go to the market and buy these components and couple. Sorry! The statement i made is wrong because you can actually go to the market and buy the components but the resultant solar system would be disastrous.
Each of these components – Solar panel, Inverter, Battery and Charge controller – should be carefully chosen based on requirements and to avoid misfit.
In order to do that, you need to make an objective listing of things you want powered on your solar system.
Let me give an example of an objevtive listing here:
– 1 LED TV (32-inch) = 41 Watts
– 1 Standing fan (OX’) = 150 Watts
– 2 Energy bulbs = 46 Watts
– 1 Laptop = 65 Watts
– 1 Decoder = 15 Watts
The above listing gives a sum of 316 Watts of Power which is your load requirement for a solar power system.
Haha! What you don’t know is that this listing is what determines the size of your inverter.
The above example means that an inverter of 500W will suffice for the load requirement.
You have just learnt how to size a power inverter. Regardless of the type of apartment you are in, this is how to be objective in choosing an inverter for your solar system because the larger the inverter, the higher the price. Just ensure your choice of component can work within your budget.
Peradventure, you have the resource to procure a power inverter large enough to power your washing machine or any other appliance/gadgets, nothing stops you from going for it. The principle is the same, just add the load to your listing.
The following are standard power inverter size you can readily get in the market:
– 500 Watts
– 800 kVA
– 1 or 1.2kVA
– 1.5 kVA
– 3.5 kVA
– 5 kVA
– 7.5 kVA
– 10 kVA
Also, note that there are different models by different manufacturers and this may be where you need a professional to help you get a durable one since you already know how to get one that suit your load requirement.
Another thing worthy of note is that the price of a power inverter varies from manufacturer to manufacturer. Some prices are a landslide away from the other even though you are bargaining on the same size of inverter.
Lastly on inverter, at least for today’s lesson, if you are constrained with resource, there are durable second-hand inverter that are less cheaper than the new ones. You can go for it.
Now that you have your listing ready, let’s look at Autonomy time of your load requirement and how to be objective in choosing a solar panel.
By autonomy time, I mean how long (hours) do you plan to use a load in a day? Do you want your TV on for 4hours, 8hours, 24hours or what?
Contrary to everyone’s opinion, are you seeing the possibilities of owning a solar power system already?
Using the objective listing above, I will assign autonomy time to each. See below for the result and what it means to assign autonomy time.
– 1 LED TV(32-inch) = 41Watts for 8hours = 328Wh
– 1 Standing fan = 150Watts for 5hours = 750Wh
– 2 Energy bulbs =46Watts for 5hours = 230Wh
– 1 Laptop = 65Watts for 10hours = 600Wh
– 1 Decoder = 15Watts for 8hours = 120Wh
You will observe in the above listing that different number of hours have been assigned as autonomy time to each gadget as I deem fit. The next thing I did was to multiply the power rating of each gadget by the autonomy time. The result is the energy (Watt-hour =Wh) required by each item in a day.
Summing up the values yielded a total of 2078Wh of energy.
This means that your choice of solar panel has to be objective enough to provide nothing less than the same energy you require, else the autonomy time you assigned will be reduced automatically.
Now, how do you choose your solar panel based on this?
Recall I said you have at least five (5) hours of sunlight in a day, ceteris paribus (you remember in economics- all things being equal). This “5 hours” of sunlight is what we want to harness and use to produce the energy we require through the solar panel.
Since that is clear, we need to find the power output of our intended panels and to do this, we simply make a division as follows:
Required Power Output (panel) = Energy Required / Autonomy time (sunlight)
= 2078Wh / 5h
Therefore, required power output (panel) = 415.6W, this is invariably the power your choice of solar panel must be able to deliver.
As at today, I don’t know of a 415.6W standard size solar panel.
But, let’s assume you found a standard size of 200W, 12V solar panel. It is evident that one-number of solar panel won’t suffice. Your best bet is to combine a couple together to achieve this.
In order to determine the number of solar panel that will deliver the power you need, you need to carry out this division.
Number of solar panels required (N)= Required Power output (panel) / standard power size (panel)
N = 415.6Watts / 200Watts
Since the panels cannot be rationalized, we round off to the nearest whole number.
Therefore, a minimum of three (3) solar panels rated at 200W, 12V is required for the solar power system.
So we can say our array is a 600Watts power array because we are using 3 panels of 200Watts each.
Remember, you can always go back to your objective listing and adjust few things that will make you work within your budget.
The following are standard sizes of solar panels and vary from manufacturer to manufacturer and from type to type.
– 1 Watt
– 2 Watts
– 5 Watts
– 10 Watts
– 25 Watts
– 40 Watts
– 80 Watts
– 100 Watts
– 150 Watts
– 200 Watts
– 250 Watts
– 315 Watts
Contrary to everyone’s opinion, you can own a solar power system too, don’t be deceived.
That you have a generator and run it for five (5) hours in a day is a sign that you are more than capable of owning a solar power system.
Permit me to sway from the lesson a bit. Let’s do the maths on what it takes to own and run the smallest generator (I beta pass my neighbour) for five hours in a day for a year. At the end, you will find out whether I’m just pulling your legs or truly you can own a solar power system.
– Cost of 650VA generator set = #32,000 (depending on the model and your region)
– Cost of fuel Annually = #156,000 (see below for the breakdown)
Let’s assume you use 4litres of fuel for 5 hours in a day although I use 4litres for nothing less than 10hours don’t ask me how.
* Cost of fuel per day= #650 (inclusive of the oil for mixture)
* Cost of fuel for a week = #3,250 (assume 5 days not 7days)
* Cost of fuel per month = #13,000
* Cost of fuel per year = #156,000
– Cost of maintenance annually = #6,000 (assuming #500 per month)
The above listing gives a total sum of #194,000 for the first year which is exclusive of repairs/miscellaneous here and there.
Are you thinking what I’m thinking? Contrary to everyone’s opinion, you are seeing the possibilities of you owning a solar power system. Imagine spending the same on solar power system and what you stand to gain-no noise, no air pollution, steady pure power supply and so on.
Just keep the above analysis somewhere safe, we may need it later.
Moving on to the lesson, “how to be objective in choosing your battery bank.”
Can you see “bank” in front of the battery? Like I said previously, the battery is used for storing charge. So, a battery is more or less like a money bank, but in this case, it stores power that can be retrieved when needed.
Whatever power your solar panel produces per time is gone/wasted unless you store or put it to use immediately and that’s where your battery comes into play.
However, in choosing your battery bank, your solar panel must be able to deliver the same amount of energy, if not more, drawn from your battery by your load else your battery drains faster than the solar panel can recharge the battery.
Batteries like the other components come in different standard sizes, different manufacturers and different models/types. The most preferred type of battery for solar power system is deep cycle batteries. You can read up on this for better technical understanding.
Be aware of the following when it comes to battery as this will aid you to objectively make a choice for one-
Common Battery Voltage:
– 2 Volts
Common Battery Ampacity:
Choosing a battery for a solar power system is not as easy as going to the market and buying a 40Ah, 2Volts battery. What purpose will it serve? For the listing we made, this choice of battery is totally useless.
So, let’s see how you can choose a battery objectively but first, recall the following in the previous lessons;
– Inverter choice = 500W, 12V inverter power system
– Solar panel choice = 3 x 200W, 12V solar panels
It is evident that the solar power system is a 12Volts system. So, whatever our choice of battery, the bank has to align to being a 12Volt system.
For example, if you choose a 2Volts battery, you will need 6 of the same type of battery to make a 12volts bank. If you choose 6Volts, you need 2 of it to make 12volts and you if you choose 12volts, you need only 1 of it to make a 12volts battery bank.
So, for the listing, I choose a 12Volts battery.
You may think our job is done on choosing battery but no, we are just starting.
Now, recall in the previous lesson that the listing used as an example gave a total of 2078Wh which is the energy requirement.
If we divide this energy requirement by the battery bank system of 12Volts, we would get the ampacity (current capability) of the battery required.
Battery ampacity (Ah) = Energy requirement / System Voltage
= 2078Wh / 12V
You will realize that the battery ampacity we need is not available in standard size.
The nearest battery size is the 150Ah which is lesser than the requirement and 200Ah which is higher than the requirement.
Choosing 200Ah seems to be the best option.
But, let’s assume we decided to go with 100Ah battery. We need to know the number of batteries to procure. All you need do is divide the required ampacity by the choice of battery ampacity.
Number of batteries required = 173.2Ah / 100Ah
It is evident we need 2 numbers of 100Ah, 12 Volts battery or 1number of 200Ah, 12volts battery.
It’s time to learn how to objectively choose your charge controller. Charge controller is crucial to the effectiveness and lifespan of a solar power system. If you have no charge controller in place, sooner than later, your battery will be damaged because the current applied to your battery terminals isn’t in any way controlled. It’s either you have your battery overcharged, undercharged or depleted of charges if you have no charge controller in place.
Also, at night when the sun is down and there is no power supplied by the solar panel, a reverse current may occur (meaning that your battery may begin to provide power back to your solar panel) which will damage your solar panel. These are the two major duty a charge controller perform in a solar power system.
Like other components, your solar charge controller comes in different types and rating. Below is the common standard sizes you find in the market:
The above ratings are also defined by different voltage levels such as 6Volts, 12volts, 24volts etc.
So, in order to size your solar charge controller, you need to know two things and what to do with it.
1) The power rating of your solar panel array, which in the example used in these lessons is a 3 number 200W panel = 3 x 200W = 600W
2) The system voltage of your battery. Also, in the example, we choose a 12volts battery system.
The result of dividing the power rating of your solar panel array by the system voltage will determine your choice of a charge controller.
Therefore, 600W / 12V = 50 Amps
This indicate that our choice of solar charge controller must be able to pass a current of 50A.
Although, we have been able to figure out how to size each components of the solar power system but what if the total sum of money required is more than the resource you have as budget?
Often times, this is where most people hang the boot. “Wetin! On top say I wan use solar shey na why I go con spend my savings, mbok.”
Fortunately, most of the components are very much available as used items and the price goes as low as 65% of a new one.
Another way is to start small and gradually upgrade as resources is available. You can always increase the size of your battery bank to increase the backup time. The same with your solar panel.
You don’t need to have a million naira before you own a solar power system. Your solar system can grow as you grow in life.
Any question? Use the comment section.