Did you know that our country has an average of approximately 2,500 hours of sunshine per year, which makes it an ideal place to exploit the many benefits that solar energy offers ?
What are the best batteries for use in solar installations?
Surely many of you already use this type of renewable energy or if you don’t yet, you plan to install a solar kit in the short term to be able to have light in a place where you currently do not have an electrical network. You may also be thinking of a solar kit that allows you to lower your electricity bill and help the environment to reduce harmful greenhouse gas emissions.
The Solar Kit for installations isolated from the electricity grid is a very suitable system for when we want to have a small energy system to power, for example, a refrigerator, a television and light sheds or homes for occasional use, which allows them to charge during the week. batteries completely to use them during the weekend. There are also Kits designed for daily use.
Its basic composition is usually: One or more photovoltaic panels , A charge regulator , An inverter-charger , Connection cables and The battery . Today we are going to focus on this last element. Without a doubt, the battery is the main element in this type of installation since it is what will allow us to store all the energy for later use, which is why it is vitally important to know how to choose the best model. Next, we will help you to do this by reviewing the different types and ways of working.
What are the best batteries to use in photovoltaic solar systems?
The batteries that store the electricity produced through the photovoltaic panels can be:
– Stationary OPzS
As you can see, there are several types of batteries that you can attach to your photovoltaic system and thus store the energy that you produce in excess. But first, it is convenient to know the characteristics of each one and its operation. Not all types of electricity production are suitable for any battery.
Monoblock batteries are those that are encapsulated in a single element. It is very common to find monoblock batteries, for example in a car or a motorcycle, although in this case they would be starter batteries and not for solar use, but although their internal design is made for a different use, they would basically be the same. They are made up of 3 or 6 internal cells of 2V each, which, connected in series, form a single block of 6V and 12V. Its cells are made of lead plates and electrolyte, which through chemical reactions can store and generate energy. Its voltage is between 6V and 12V. This type of battery is designed for small photovoltaic installations where the value for money compensates.
These are lead batteries in which the electrolyte is impregnated in a mesh of absorbent material and totally sealed. They are usually always in monoblock format of 6 or 12V.
It is characterized by:
– Being completely sealed. Battery acid does not spill and does not give off gases. That is why this type of battery does not require maintenance , and they have valves that regulate the escape of gases to prevent them from deforming and exploding.
– Vibrations do not affect them.
– Ideal for deep discharges.
– Large number of charge/discharge cycles.
– They support higher charging current than other conventional lead batteries.
AGM batteries are inexpensive and widely accepted in the market. They are highly recommended for small solar installations since they are ideal for deep discharges, they have a high charge/discharge number (useful life cycles) and with weekend or sporadic use they have a useful life that can be up to about 4-5 years.
These are lead-acid batteries in which the electrolyte is in a gel or pasty and consolidated state and they are also totally sealed and maintenance-free. The gel component is due to the mixing of the liquid electrolyte with a material that is then left with the consistency of a gel. This type of battery has a high-quality cyclic operation, which makes it ideal for small-medium sized installations whose purpose of operation is long periods of time. They are also suitable for systems that are difficult to maintain.
These batteries are normally found in a 6 or 12V monoblock format, although they also exist in 2V cells with higher capacities for medium-large installations.
This type of battery allows a depth of discharge between 80 and 100% of the battery capacity. It supports high intensities of current charges and discharges with a performance superior to any type of battery. In addition, in most cases it has a very high number of useful life cycles (charge/discharge cycles) and compared to lead-acid battery technologies, they are not affected as much by the depth of discharge performed compared to the life useful battery.
These batteries are usually found in small format at 12 or 24V, for large format they are found in 48V batteries and for some applications such as self-consumption with connection to the network, the most used are the high voltage ones, reaching voltages that can even exceed 400V.
Unlike lead batteries, lithium batteries incorporate electronics, which in most cases requires communication between the battery and the charger and inverter, resulting in not all lithium batteries being compatible. with any team. In batteries of a certain capacity, normally each manufacturer has approved lithium batteries for use with their equipment and these are the only ones that we can use.
OPzS stationary batteries
OPzS stationary batteries, also known as solar accumulators or solar batteries , are batteries made up of 2-volt elements connected in series until the desired working voltage for the solar installation is reached. In this way, a 12 volt stationary battery is made up of 6 2v elements connected in series and a 24v stationary battery is made up of 12 of these elements.
The 2-volt elements, also known as cells or batteries, can have capacities between 200Ah and more than 4000Ah, which allows configuring solar accumulators of the desired voltage and sufficient accumulation capacities for any application. Due to the fact that it is not recommended to connect batteries in parallel (whenever it can be avoided), and that the accumulation capacities of 12V monoblock batteries are limited to about 250Ah or 300Ah, it is necessary to use OPzS stationary batteries to obtain capacities. of greater accumulation.
OPzS stationary batteries have been designed for types of applications with low, medium or high consumption but with continuous daily use . Although they are batteries with a higher price than monoblock batteries, they are perfect for installations with continuous daily consumption and for long periods of time. In this type of use they obtain a very good durability/cost ratio, especially with respect to monoblock batteries. Its useful life is approximately 20 years if the accumulation in batteries is well calculated to maintain the appropriate depth of discharge. And this is so because, as with all lead batteries, its useful life is quite affected if high depths of discharge are regularly carried out.
Therefore, as a conclusion, we can say that depending on the total capacity that we need, the use that we have to give to the installation and the budget that we have, we will have to choose the option that best suits our needs.