Isolated photovoltaic installations are those that are not connected to the network. They are used to produce electricity for the self-consumption of a home or warehouse, but not to sell surplus energy produced to the distribution company.
Components of an isolated photovoltaic installation
Isolated photovoltaic installations are sometimes the only alternative to have electricity in remote places. There are four components of an isolated photovoltaic installation :
- Solar panels: are the components that deal with transforming the energy of solar radiation into electrical energy.
- Charge regulator: it is the electronic device that manages the battery charge.
- Battery: stores the electrical energy produced by the panels so that it is available when it is night or there is not enough sunlight.
- Inverter: converts the photovoltaic solar energy produced by the panel and stored by the battery from direct current to alternating current, which is the one used by most electrical devices.
These solar kits sometimes come in kit form, including all the necessary elements to have a photovoltaic installation, although we do not recommend them due to their poor quality .. They can also be purchased separately. Depending on the use that we are going to give to the isolated photovoltaic installation, we will have some components or others, because not all of them are always necessary. Thus, for example, we find solar kits made up only of the solar panel and an inverter or frequency variator because they are used to start water extraction pumps or in irrigation systems. In these cases, we do not need the regulator or the battery. The inverter can also be absent if we want to power electronic equipment that works with direct current. This is common in measurement stations or control and surveillance equipment, which usually use cameras that work with direct current.
Next, we explain in more detail the characteristics of each of these components.
Solar panel is also known as photovoltaic module. It is the central device of any isolated photovoltaic installation, since it is responsible for converting the solar energy that it captures through its photoelectric cells into direct current electrical energy. This conversion is achieved thanks to the photoelectric effect: the cells capture photons of solar radiation and transform them into electrical energy.
There are different TYPES OF PHOTOVOLTAIC PANELS . We can classify them by their output voltage (12 V or 24 V) and also by the number of photoelectric cells they contain. The most common panels in isolated installations are those with 36 cells of 12 volts, those with 72 cells of 24 volts and the panels of 60 cells, also 24 volts.
If we are going to make occasional use of the installation or have low consumption, it is advisable to use 12-volt panels. On the contrary, if we are going to have regular and important consumption, we will have to opt for 24-volt panels, whether they are 60 or 72 cells.
solar charge controller
It deals with managing the energy production of solar panels. The solar charge controller has a dual function. When we have direct current consumption, such as 12-volt bulbs, the regulator is responsible for managing the consumption demand to the panel. On the other hand, if the installation has batteries, the regulator is in charge of recharging the batteries, accumulating the generated current that is not consumed immediately.
Solar regulators can be of two types: PWM or MPPT .
They have a different operation and each one is indicated for one type of installation or another. If we use 12-volt or 24-volt photovoltaic panels with 36 or 72 cells, we will have to use PWM regulators.
On the other hand, in installations of solar panels with 60 cells or panels with voltages outside the normalized ranges, it is necessary to use MPPT regulators.
Solar batteries accumulate the energy produced by the panels. When there is no sunlight because it is night or not enough energy is being produced, the installation pulls the batteries to consume the current it needs. Batteries are a must when we are homes or we need to consume power when there is little or no sunlight.
There are different kinds of batteries on the market. The most typical classification is the one that divides batteries according to their construction method. Thus, we have monoblock or stationary batteries . We can also divide them according to whether they are open or sealed . We must also highlight lithium batteries, which are usually the most installed at the moment due to their numerous advantages such as stability, performance, guarantee and zero maintenance.
The most used element in the manufacture of batteries is lead, although those built with lithium are gaining ground.
We have to pay great attention when choosing the type of battery for our installation. Batteries are expensive and it is complex to resize your installation in the future if we need more capacity. It is also necessary to know the useful life of each type of battery, because depending on the use that we are going to give it, we will need more or less long-lasting batteries, which are more resistant to charge and discharge cycles.
If we have a sporadic and reduced consumption, we can opt for monoblock batteries, cheaper, but less durable. If we are going to make a large consumption and use them regularly, it is preferable to opt for stationary batteries. The useful life of a monoblock battery can be around four years, while some stationary batteries can reach 20 years of useful life. Although they are more expensive, they will have a longer amortization period.
The SOLAR INVERTER is responsible for converting the direct current of 12 or 24 volts into alternating current of 220 volts . The inverter is an essential element for isolated homes because the appliances we use and the lighting work with 220-volt alternating current. If it weren’t for the inverter, we would have to fill the house with transformers from direct current to alternating current, which, in addition to being expensive and inconvenient, is also not an efficient solution.
In isolated solar installations we find different types of configurations depending on the service they have to provide. We will also have different levels of investment depending on the energy demand that we need at that time.
We hope we have resolved your doubts about the components of an isolated photovoltaic installation.