A photovoltaic installation should not be associated only with the incorporation of solar panels on the roofs of our homes. There are other components that we must know when we want to be more independent from the marketers and generate electricity from solar energy. Elements such as supports, monitoring systems, or protection equipment are also part of the installation but, above all, the inverter will be one of the most important pieces that will allow us to enjoy solar self-consumption.
In the following article, we will explain in detail what a solar inverter is, how it works, the types and which one to choose for your home.
What is a solar inverter?
The solar inverter is the essential component that will allow anyone who installs solar panels in their homes to enjoy the energy from the sun, that is, it converts the energy generated by said solar panels into electricity.
And why is this element necessary? The energy production carried out by the modules is transformed into direct current that cannot be used in homes, nor is injected into the electrical electricity grid.
This is where inverters for solar panels come into action, converting that continuous energy that we cannot take advantage of into alternating current for our daily energy consumption. In this way, it will allow us to make use of electrical appliances, lighting, or other functions of the home that need electricity.
In addition to performing this relevant function, the inverter will optimize the production of energy generated by the photovoltaic solar panels (such as monocrystalline solar panels or polycrystalline) to achieve the maximum possible performance of the installation.
Regarding the useful life of a solar inverter, we can speak of an approximate duration of up to 10 years, due to the electronic components, which can be easily replaced.
We must also take into account the location of the solar inverter in the house because it can generate some noise, approximately 25 dB, similar to what a high-efficiency refrigerator can be. On the other hand, inverters lose performance if they are exposed to the sun for a certain time since it increases their internal temperature.
Therefore, we must place it in an unusual and hardly traveled area of the house where the equipment cannot be a nuisance for us and is not directly exposed to the effect of the sun.
The main characteristics of inverters
We have already seen that solar inverters play a very important role in the installation of a photovoltaic system. Now we will see what its main characteristics are:
- As we have mentioned before, its main function is the transformation of direct current into alternating current that allows the operation of electrical devices with energy from the sun.
- Optimizes the production of energy generated by the small solar panels, maximizing the performance of the system.
- It must contain protective equipment that will monitor performance and electrical activity so that energy production is stopped in the event of a system failure or short circuit.
- Monitoring. A follow-up of the production generated by the solar panels will allow us to know if there is a fault in any of them and if we must make the appropriate arrangements to prevent the performance of the installation from decreasing.
Operation and installation of solar inverters
Once we are clear about the main functions of solar power inverters, we are going to see exactly how this component works in a photovoltaic self-consumption installation.
Solar panel receives sunlight, which is later transformed into electricity. But this electricity is completely converted into direct current which is not feasible for electrical consumption in our homes. So how can we use that electricity from solar energy? The answer lies in the solar inverter.
This essential component of any photovoltaic self-consumption installation will transform direct current into alternating current. The energy generated by the solar panels is sent directly to the inverter to carry out this transformation of currents and, finally, enjoy the electrical energy from the sun and use it for domestic use.
Regarding the installation, we must take into account aspects such as the proper functioning of the electrical circuits in our home, the location of the inverter, the connections and even the fuses.
For this reason, we recommend contacting professionals in the sector who can help you carry out a correct installation. At Otovo, we have a large number of certified installers to help you install your photovoltaic system and answer any questions related to the process.
Types of solar inverter
It is clear that the primary purpose of a solar power inverter is to transform current energy into alternating current to use the solar energy production that our solar panels have generated and, in this way, use the electrical appliances in our house. There are several types of solar inverters that we will differentiate according to two classification criteria:
According to the installed power and electrical configuration
According to the purpose or application of the off grid solar system
Referring to the electrical configuration classification criteria, we can differentiate between single-phase and three-phase inverters. We explain below what each one consists of and what differentiates them.
Single phase inverters
Single-phase inverters are used in single-phase electricity grids, that is, they only use one phase and one alternating current. Its normalized voltage is set at approximately 230 volts, allowing a maximum power of 14.49 kW to be installed, although the most powerful single-phase inverter on the market is 8.2 kW. This type of installation is very common in almost all houses in our country, being used largely for heating and lighting. But, how can I know if my installation is single-phase? Easy! You will only have to go to your electrical panel and verify that the devices are double, as shown in the following image:
Three-phase inverters
Three-phase inverters with solar panel for rv or marine, unlike single-phase ones, are made up of 3 phases and 3 different alternating currents, and their normalized voltage is set at 380-400 volts and 50 Hz. Therefore, we are talking about installations that are very suitable for large homes with a swimming pool, companies, and industries where the dimensions of the photovoltaic installations are medium and large. It is true that we can find this type of electricity grid in small homes, but it would not be the most common. As in a single-phase installation, to find out if we have a three-phase electrical system in our home, we must go to our electrical panel and check that we have a triple device.
With an electricity grid connection
Once we have found out if we need a single-phase or three-phase inverter for the home according to the electrical configuration of our house, we can choose solar inverters with a connection to the electricity grid or with an isolated connection. The first type of technology will allow us to pour surpluses into the electricity grid and systems that are not connected to the grid will need several solar batteries to store the energy that has not been consumed, assuming 100% independence from the traditional grid. . However, we do not recommend disconnection, since in the case of entire days without sun, the home risks being left without electricity.
Within each typology, we will find the different types of technology that can be applied.
The photovoltaic installations where electrical inverters with connection to the electricity grid have been installed, transform the solar energy from the solar panels into electricity suitable for domestic consumption with the possibility of pouring the surpluses generated into the electricity grid and obtaining the appropriate economic compensation.
In other words, the inverter is the “brain” of our installation that decides where it consumes (panels, electricity grid, or, where appropriate, batteries) and operates the rest of the elements so that we have energy at home.
We differentiate between five types of electrical inverters connected to the grid: string or chain, microinverters, hybrids, power optimizers, and intelligent modules.
String, chain, or centralized inverters
Solar panel installations that include string, and chain, also called centralized inverters, are normally used for photovoltaic systems installed on roofs that are not affected by shadows. Currently, they are the most widely used and economical on the market, in addition to having simple maintenance that will not take up time thanks to its easy access nor will it entail additional cost.
But how exactly does it work? In installations that include string inverters, each of the panels that make up the system is connected in series or by chains. There are inverters that accept several strings, although those with low power can be configured with a single string, that is, the energy production that has been generated by each line or string of panels will be limited to the panel that has generated the least power in said string. Expressed more simply, this means that if any of the solar panels that have been installed are affected by shade at certain times of the day or year, the total power of the chain of panels will be considerably reduced until it reaches the power of the panel that is being affected by the shadow.
Therefore, this type of inverter is perfect for geographical areas where solar radiation remains constant annually and no solar panel is affected by shade.
Microinverters
Micro inverters for a photovoltaic panel installation have a different operation than string inverters. In this case, each panel contains a solar energy inverter, which means that it is not necessary for the production to be directed to a single inverter, but thanks to the fact that each of the solar panels contains microinverters that can transform the energy from direct current to alternating current from the roof itself. Unlike string inverters, the production generated by one panel does not affect the rest, thus reducing their performance.
This type of technology has become more viral in recent years among the solar self-consumption of homes, betting on a more powerful system that will achieve greater performance and efficiency of the photovoltaic system. In addition, they allow monitoring of the solar panels, knowing first-hand if the performance has been affected by any failure in the system to take the appropriate measures later.
What is the drawback? The price is higher since we are talking about small inverters embedded in each of the panels, making it difficult to repair due to difficult access.
Hybrid inverter
We can also find some models that combine it with the electrical electricity grid, although it is not the most common, having them in cases of blackouts such as the hybrid inverter.
A hybrid solar inverter has the same function as a conventional string inverter but in addition to transforming the energy coming from the panels for domestic use, it manages the charge/discharge of energy in battery systems (12 volt lithium battery or 24-volt lithium battery) for use at times when the panels are not available. producing. These inverters are configured to maximize the life of the batteries, which are the most expensive element of the installation. It converts direct current into alternating current managing the production of energy from the sun with the batteries and discharging the generated surpluses to the electricity grid. It alternates the use of batteries with the inverter, that is, when the battery has a low level, the inverter will intercede by consuming energy from the external electrical electricity grid.
This type of technology is designed to achieve the maximum self-sufficiency of the system and to allow us the maximum possible energy savings, however, it has a much higher price than a system without batteries.
There are some hybrid inverters, known as smart, that are capable of charging the lifepo4 battery with energy from the electricity grid at times when its price is low to use in cases where the photovoltaic system cannot supply the electricity demand of the home.
Power optimizers
Installations with power optimizers contain the best attributes of string inverters and micro-inverters. They are located on the roof embedded in the back of the solar panels like micro inverters, but they do not transform the energy directly from each of the modules, but rather it is sent to a centralized inverter as is the case with inverters. chain.
If we compare it with string inverters, we will see that optimizers are much more efficient. Why? Because the centralized inverter looks for power taking into account the set of solar panels, the power optimizers intervene on each panel and not on the set, therefore, the point where the most power is generated can be located. Therefore, if a solar panel is affected by shading, the overall power of the system will not be drastically reduced thanks to being connected to an optimizer.
The good thing about these types of systems is that they are cheaper than micro-inverters and require much less maintenance. They also improve the efficiency of the solar generators installation thanks to the option of monitoring the performance of each of the modules.
Smart module
The desire to improve inverter technology more and more does not stop. Thus, intelligent modules have emerged, managing to be an improved version of power optimizers. These modules are integrated into the solar panels and, although they are still in the experimental phase, they could further reduce the cost of maintenance thanks to a simpler installation.
The cost is higher than other inverters such as the string, but it offers numerous advantages that will considerably increase the profitability of the installation:
Performance is measured per solar panel and not as a whole as is the case with string inverters.
Installation times will be significantly reduced thanks to the integration of an optimizer in each module, making installation much easier. There is no need to incorporate new additional materials to the installation, therefore, it will also result in a reduction in labor costs.
Solar panel maintenance is reduced thanks to the fact that the optimizers located in the upper part of the intelligent modules are easily removable, allowing the installation to be kept clean or to make changes if a fault occurs in the system.
Not connected to the electricity grid or isolated connection
Isolated connection inverters, also called non-grid connected, are a type of technology that, as the name indicates, completely dispenses with the external electrical electricity grid, being mandatory to have a battery where all the energy can be stored. solar generated through the panels. The inverter extracts the energy from the battery and converts the direct current into alternating current so that we can use it in our day-to-day, feeding our electrical devices. Generally, this type of inverter is used in areas with little or no accessibility to the electrical connection, such as in motorhomes or boats.
Isolated inverters
Inverters for isolated installations (disconnected) from the electrical grid work in a very similar way to hybrid inverters for grid-connected installations, however, what makes these equipment special is that they are capable of generating their own electrical grid according to the electrical regulations (230V/400V 50Hz).
Some of them have the particularity of not having the battery charge/discharge control equipment incorporated, this being a different piece of equipment called a regulator.
Inverter prices for solar panels
The inverter is a key piece for the installation of a photovoltaic self-consumption system in our home. Its price can vary from $300-$400 (micro inverters) to $5,000 (50 kW three-phase inverters). This price variation depends on the power, quality, and type of solar inverter that will influence whether we are talking about grid connection or isolated connection, as well as the type of installation we have in the house (single-phase or three-phase). As we mentioned before, the inverter is the “brain” of the installation, and therefore, the technology entails this higher cost.
A good investment will allow the inverter ( 12v inverter or 24v inverter)to last longer and achieve greater efficiency. We must analyze which one meets the necessary requirements for the consumption of our home, achieving maximum performance.
How to choose the most suitable inverter?
Once we know all the information, a million question arises: how to choose the most suitable inverter for my solar panel installation?
The first of all is to know the energy consumption that we make in our homes from our electrical devices. Based on this, we will be able to evaluate if we need a larger or smaller, single-phase or three-phase installation and if we are connected to the electricity grid.
If you are not connected to the electricity grid, you should opt for an isolated system with a storage system. On the other hand, we must see that the production of our photovoltaic system is consistent with our consumption. Self-consuming a lot and throwing away little energy.
We must also take into account the inverter brands that exist in the market and that they can offer you. We work with inverters that stand out for their efficiency and safety, being a very safe alternative to install in homes and these are: Renogy, SolarEdge, and Huawei.
Inverters have brought a lot of convenience to our lives. Choosing the right inverter can allow you to enjoy clean energy and save a lot of money.
