Category: Solar Panel Energy

How to charge a battery with a solar panel

February 8, 2023 / Blue Solar Panel Staff / 2 Comments

The option of connecting photovoltaic solar panels to a battery is a cost-effective and suitable option so that you can count on your equipment at full performance, whenever you will need them. The cases in which this option is most useful are for equipment that are used outdoors, such as tractors, motor boats, golf carts… Which, on many occasions, are not used for days or even months.

Connecting the battery to the panels is a simple task. However, in order for the solar panels to be able to supply your battery, you must first calculate how many panels you are going to need. To do this you will need to find out the amperage of your battery and the capacity of your solar panels. Here’s how to do it.

First step, how many Ah does the battery have?

First of all, you must find out what is the amperage per hour rate of the accumulator or battery you want to charge. You must know that, a battery of the calls of wet cells, diminishes its amperage around 1% daily when we are not using it. So, for example, we would need a solar panel capable of generating 0.5 amperes per hour per day, in case we want to keep a 50 amp battery always charged. The disadvantage is that the photovoltaic solar panels are classified according to their capacity in watts, so we will have to apply a simple mathematical formula to solve our unknown.

If you want to convert the capacity of a solar panel from watts to amps, you must divide the capacity of the panel in watts by 15. For example, a solar photovoltaic panel with a capacity of 50 watts is capable of obtaining about 3.33 amps. Then, if we take into account possible obstructions during sunrise and sunset, bad weather and possible clouds that may come out during the day, a solar panel is capable of supplying about four hours of output per day. Thus, a solar panel with a capacity of 50 watts will produce 4 × 3.33 amps per hour per day, or 13.33 amps per hour. So, the panel will be completely sufficient to get our 50 amp battery, can remain with its full charge capacity to the maximum.

Second step, make the connections.

Once we have calculated our needs, we can now move on to making the connections. In the first place, you must connect the positive cable with a fuse, from the photovoltaic solar panel to the battery. In this way we will be able to prevent us before a possible explosion or fire of the accumulator, in the case in which a short-circuit in the cable takes place. Later the negative cable of the photovoltaic solar panel is connected to the negative terminal of the battery.

If it is necessary to interconnect panels to charge your battery, we recommend that you connect your solar panels in a parallel circuit. In this way, you will have the option of using panels with a lower cost and also lower power, thus achieving the same effect as with a solar panel with more energy.

To connect the panels in parallel, you must connect the positive wire of the first panel with the second one, and so on consecutively. Perform the same operation with the wiring of the negative pole, and finally link the remaining wires to the battery.

Now you must calculate the amperage of your solar panels that are connected in parallel. You must know that the solar panels that have been connected in parallel circuits, continue conserving the same electrical tension, and the intensity of the current is added. That is to say, if we have five solar panels with a capacity of 5 amperes, we will get 25 amperes of power, and all of them would have the same constant voltage.

How much energy does a solar panel produce

February 8, 2023 / Blue Solar Panel Staff / 0 Comments

When referring to self-consumption, one of the most frequently asked questions is how many kWh a solar panel produces. The answer to this question depends on the price of the project and the space for the installation. Knowing in depth how many kWh can produce a plate, depends on the power and different factors that you should keep in mind. The panels have different numbers in reference to their power, but you should understand what they mean.

How much kWh does a solar panel produce

The answer to this question will depend on the panel since there are different power ratings. Another very important aspect to keep in mind is that over the years the power of the panels has been increasing. At the same time, prices have been decreasing.

The power generated by solar panels is measured in watts (W). There are different powers in the panels, you will find it indicated on the plate that you are looking for your installation. The power between solar panels ranges from 250W to 300W of energy. But it is true that nowadays it is common to see solar panels in homes with higher powers, such as 500W, there are also some of lower powers such as 150W.

In the case that you have a common panel of about 300W, this indicates that for every hour of sunshine the power generated is 300W. This leads to the following calculations, suppose it is a sunny spring day, in a warm area, the calculation would be:

300W x 5 hours of sunshine per day = 1500W or what is the same, 1.5 kWh per day.

To make the annual check, suppose that these five hours are an annual average (compensating the hours of less sunshine in winter by the hours of more sunshine in summer), you will make the following calculation:

1.5 kWh per day x 365 days of the year = 547 kWh per year for a 300W solar panel.

With this data you can make approximations, the consumption of kWh needed by an average home is about 8000kWh per year. This allows you to make the installation with the size and panels you need to meet the needs of your home.

The hours of sunshine and its impact on the kWh produced by a solar panel

In the previous example it is simple, calculating 5 hours of sunshine in a warm area, in the spring-summer season, but is it too little for the cities in the south of the country?

What you should consider when buying a panel and the first thing you should look at is the wattage of the solar panels 300W or 500W. These numbers refer to the power that the panels can provide under optimal conditions.

But these conditions are not always and not everywhere.

Thus, there may be 6, 9, or 12 hours of sunshine in both northern and southern cities in summer, but very different hours of sunshine.

The incidence of the sun on the panels is higher in hot areas, so it is more likely that in these areas the panels reach the appropriate power 300W during the year. But in other cases it will be more difficult.

The new materials and innovations that are made in solar panels, are getting that even on days in which the weather conditions are not suitable, you can extract energy, without reaching the maximum.

These are the three most important factors to take into account when it comes to knowing how much power a solar panel offers:

1. The power of the panel, this refers to the watts of the plate that you see in the catalog or on the label.

2. The hours of sunshine that receives the place where the plate is to be installed.

3. The incidence of sun in the place where the installation is carried out.

It is true that to use this tool you must have some technical knowledge about photovoltaic energy.

The solar panels have a nominal generation power, which reaches in suitable conditions and should be guided by it.

However, it is true that it may not always reach this power, depending on the geographical area in which the installation is located. Therefore, you must take into account the three points mentioned above. Without them, you cannot make a real calculation of the kWh that the panel of your installation can generate.

What kWh output should you choose for your solar panel?

The answer to this question depends on:

– The budget you have.

– Your energy consumption and how much you want to cover with solar energy.

– The amount of space you have available for the installation.

The solar panels that have a higher power have a larger size, but can occupy a smaller total space. The price of these panels is higher, although it can be, that the set comes out more economical than a greater number of plates with less power.

If you take into account all the tips in this post, you will be able to solve your doubts and find your way around kWh and panels of all types.

How many solar panels do I need? Calculate it yourself

June 23, 2022 / Blue Solar Panel Staff / 0 Comments

The number of solar panels that any photovoltaic installation will need will depend on the energy consumption, which can vary between low, medium and high.

How to calculate solar panels?

Calculating the number of solar panels is one of the most important procedures in the implementation of a photovoltaic installation. This step is technically known as sizing and is carried out taking into account the amount of energy consumed (measured in kWh) during a year.

The following table shows how the number of solar panels required can be calculated according to consumption. Specifically, an electricity bill is used to find out the annual consumption in kWh, quantify the number of solar panels that will be needed and forecast their installation cost.

Solar panels calculation

Type of consumption	Electricity bill month	Consumption kWh/year	No. of solar panels	Price of installation
Under	Less than 50	2,400 kWh/year	Less than 3 panels	Around € 2,500
Low – medium	50 – 100 €	3,600 kWh/year	3 – 6 panels	From 3.300 €
Medium	100 – 150 €	6,000 kWh/year	6 – 9 panels	Starting at 4.800 €
Medium – high	150 – 200 €	8,400 kWh/year	9 – 12 panels	From 6.300 €
High	200 – 250 €	10,800 kWh/year	12 – 14 panels	From 7.500 €
Very high	More than 250 €	12,001 kWh/year	More than 14 panels	From 9.100 €

Approximate figures

In this way, and following this table, any person can know how many solar panels he/she will need to be self-sufficient. All you need to do is

Have access to the last electricity bill you received.
Place yourself in the table, in the price range that corresponds to your case.
Take a good look at the other consumptions that you have near your cell, because the final calculation may vary.

Solar panels calculator

Another option, also free and online to identify the number of solar panels that will be needed, is to use a solar panels calculator. This is a very useful tool, which is made available to any user by the installation companies, and which allows you to quantify the number of solar panels and the price of their installation.

These solar panel calculators work in the same way as a form. Through a question-answer system, they are able to identify the user’s energy needs. In such a way that, at the end of the questionnaire, they can issue an indicative budget.

In some cases, this final document also provides an estimate of savings and a financed installation price. In fact, this is the case of the online solar panel calculator that BlueSolarPanels has set up.

Through it, a user, whether the owner of a house, a commercial premise or belonging to a community of neighbors, can get a general idea of the number of solar panels that will be needed.

Although a multitude of similar tools can be found online, most solar panel calculators usually ask the same questions to the user, as these are necessary to provide any kind of indicative installation budget. Some of the most common ones are:

Asking for the type of building where the panels are going to be.
Asking for the address or zip code
Knowing the energy consumption: through the electricity bill or the CUPS number.
Inquire about the type of roof on the property
Need some personal information such as email or telephone, to detail the information provided.

Why use a solar panels calculator before installing? Before installing it is highly recommended to use a solar panels calculator. This tool allows users to get an insight into photovoltaic energy and learn first-hand about key aspects to make the decision to switch to solar self-consumption.

How many solar panels do I need for a house?

To illustrate how to calculate the number of solar panels based on energy consumption, let’s see how many solar panels would be necessary for a house. Specifically, for 2 types of houses:

The first dwelling is a rural house, of sporadic use, which has a low energy consumption.
The second dwelling is a residential house, which has a high energy consumption.

We are going to observe, comparing both cases, how the number of solar panels needed increases based on a higher or lower use of household appliances.

Number of solar panels as a function of plugged-in items

Elements plugged into the grid	Number of solar panels you will need
Rural house of sporadic use with low consumption One refrigerator One TV Lighting (8 bulbs) Washing machine	You will need 4 solar panels
Residential house with high consumption Refrigerator Washing machine Microwave 2 televisions 1 computer Toaster Radio Iron 6 fans 6 lamps 12 light bulbs The motor of the purifier for a removable swimming pool Daily cell phone charging	12 solar panels

Also, apart from energy consumption, other factors can be used to calculate how many solar panels a house needs. Mainly, there are 2:

The surface area of the house (m2)
The number of people living in the house

How many solar panels do I need for a house of a specific m2?

How many solar panels do I need for a 200 m2 house?

The number of solar panels needed for a house of 200 m2 is between 8 and 12 solar panels. This is a large property, which will need several panels to supply the lighting and other domestic energy it uses.

How many solar panels does a 100 m2 house need?

Typically, the number of solar panels being installed on houses with a surface area of 100 m2 is between 4 and 8.

How much does a solar panel produce per m2?

A 460 W solar panel can produce about 350 kWh per m2 per year.

However, the energy production of the solar panel per m2 will depend on the power, the material, the size and the other characteristics that make up the price of solar panels.

6 key aspects of the price of solar panels

Power
The higher the power, the higher the price. It is measured in peak power (Wp).

Cells
Transform the sun’s rays into electricity. They can change the size of the panel.

Material
Monocrystalline is more efficient and expensive. Polycrystalline is less efficient and less expensive.

Aesthetics
is determined by the color, such as All Black. And also by the flexibility of the panel.

Size
There are solar panels of 0.5 cm and can exceed 2 meters. They are measured in length x width x height.

Brand
There are brands that are more expensive because of their prestige, but new, more economical ones are emerging.

Number of solar panels according to the number of cohabitants

Finally, another element that could be taken into account to calculate how many solar panels a house needs is to analyze the number of cohabitants. Normally, a house with a large family tends to need more energy than a house with a married couple. Even if both have the same square meters.

Calculation of solar panels according to the number of cohabitants

Number of cohabitants	Number of solar panels	Price of the installation
2 persons	3 solar panels	3.300 €
6 persons	9 – 12 solar panels	6.300 €
4 persons	6 persons	9.100 €

Also, and within the sizing process, users are often interested in the number of solar panels needed to be able to consume a number of kilowatt hours per year, or the number of solar panels needed for their installation to have a certain power (Wp).

Here are the most frequently asked questions on this subject.

How many solar panels do I need according to the Wp power?

How many solar panels do I need to generate 5 kw?

With a good orientation and inclination, you would need 8 solar panels of 460 Wp to generate 5,000 kWh/year of consumption.

However, if you want to have a photovoltaic installation that reaches 5 Wp, you would need 11 solar panels of 460 Wp.

How many solar panels do I need for 4000w?

Users who are interested in having a solar panel installation to consume 4000 kWh/year will need 6 solar panels of 460 Wp.

But if they want to have an output of 4000 Wp they will need 9 solar panels.

How many solar panels do I need for 3000w?

With a good orientation and inclination, 4 solar panels of 460 Wp would be needed to generate 3,000 kWh/year.

However, in the case of a self-consumption installation with a power of 3000 Wp, 7 solar panels will be necessary.

How many solar panels do I need for 20,000w?

35 460 Wp solar panels are needed to generate 20,000 kWh/year.

And if you want to have an installation of solar panels that can reach 20000 Wp, 43 solar panels would be needed.

How many solar panels do I need for 2000w?

With a good orientation and inclination, 3 solar panels of 460 Wp would be needed to generate 2000 kWh/year of consumption.

On the other hand, to have an installation that reaches 2000 Wp, 5 solar panels would be needed.

How many solar panels do I need for 1500w?

To consume 1500 kWh/year, 2 solar panels are needed. But to have an installation of 1500 Wp, 4 solar panels of 460 Wp would be needed.

How many solar panels do I need to generate 1 kw?

To have a self-consumption installation and to be able to consume 1 kWh/year, 2 solar panels are needed.

However, if what is needed is to have an installation that reaches 1 Wp, 3 solar panels would have to be installed.

Step by step calculation of solar panels

To determine the number of solar panels needed for a self-consumption installation, installation companies use a special formula: the solar panel calculation. This is a complex formula, which should only be carried out by qualified technicians. This is the only way to ensure, as they say in the industry, the correct sizing of the photovoltaic system.

In order to carry out the calculation of solar panels, it is necessary to have a series of technical information:

Data for the calculation of solar panels

User data

Annual consumption in kWh. You can see it in the electricity bill and multiply it by 12.
The annual consumption in the example will be 8,400 kWh/year.
Hours of light per year. It will be necessary to multiply the daily hours of light of the province by the days of the month during a year.
In the example it will be 2,190 hours (6 hours x 30 days x 12 months).

Technical data of the panel

Solar panel power. It can be found in the technical data sheet of the product. They are between 300 and 500 Wp.
In the example the panel potential will be 460 Wp.
Production loss of the panel. This percentage can be found in the data sheet of each panel.
In the example it will be 1.15%.

Calculation formula for solar panels

1.- Calculation of daily consumption

Annual consumption kWh / Light hours h
Example: 8.400 kwh/year / 2.190 h = 3,8 kw

2.- Introduction of the production loss factor

Daily consumption kW x Production loss factor %.
Example: 3,8 kW x 1,15 % = 4,4 kw

3.- Obtaining the number of plates

Daily production / plate power x 1.000 (to convert to Kilowatts)
Example: 4,4 / 460, x 1.000 = 9,7
Answer: 10 solar panels are needed for a consumption of 8,400 kWh.

The calculation of solar panels changes according to the province. In order to make this calculation of solar panels more precise, installers take into account more technical factors such as the production of the panel according to the geographical area. This means that the number of solar panels needed varies from one province to another, even if the building has the same energy consumption.