Are batteries necessary in a solar panel installation?

Solar panel batteries are the most expensive components of an installation. Depending on the type of battery for the solar installation that is used, the price can vary from 500 euros to 10,000 euros or more —in the case of the most modern models made with lithium—. That is why the question often arises as to whether these are necessary in a solar installation or if they can be dispensed with. Well, in this article we offer you a clarification about it. We explain what the solar panel system with batteries is and other issues related to the characteristics of the batteries. Read on to find out!

Installation of solar panels with batteries: Is it necessary to install batteries?

the answer is it depends. As we have explained on several occasions in this blog, we find different types of solar installations that may or may not require the use of batteries. These are network solar installations and isolated solar installations:

• Solar network installations: These are the self-consumption solar installations that are carried out in public buildings, neighborhood communities and individual homes, such as bungalows and chalets. In this type of system, it is not necessary to install solar panels with batteries since the property is connected to the general electricity grid and, in the event of energy insufficiency, the installation will take electricity from it.
• Isolated solar installations: These are solar installations that do not have access to the general electrical network, for example, a house in the countryside. Although also, those solar installations used for the extraction of water through solar pumping or installations in caravans —since the vehicle battery cannot be used—.

It is important to make it clear that in some solar installations connected to the general electricity grid, the batteries can be used simultaneously —although at first it may seem like an absurd expense—. The advantage of having a battery in an installation connected to the network is that of having energy for self-consumption when the daylight hours run out, but with support (the electrical network) in case of need.

Types of batteries for solar panels

The batteries of the solar panels are the elements of the installation that allow store the electrical energy that is produced for later use at the time you want. The installation of solar panels with batteries allows you to completely disconnect from the electrical network, which is a great advantage for users at an economic level. However, depending on the type of battery or the materials with which it is made, the charging capacity, as well as other features —such as the charging speed and its useful life— will vary between one and the other. If you wonder what solar panel batteries are or the types of batteries for solar panels that exist, pay attention to the following clarification:

• AGM batteries: AGM solar batteries are those that are indicated for small installations. They generally have a shelf life of 5 to 10 years. These are very versatile and usually withstand discharge cycles well. They do not require maintenance.
• Monobloc batteries: They are a type of batteries used in isolated low-consumption installations or for occasional use, see, for example, for home lighting. These types of batteries usually have a useful life of 4 to 5 years. They are usually lead acid. They require maintenance.
• stationary batteries: These batteries are used for installations with high levels of consumption and continuous use. These are battery models with an excellent value for money. They usually have a capacity of up to 3,000 charge and discharge cycles – they can be discharged up to 80%.
• gel batteries: These are used for homes with low consumption, in general. They usually have a useful life of 1,200 load cycles. They can be discharged up to 60%.
• lithium batteries: These are the most modern today, with the fastest loading times. These can be used in any installation and do not require specific maintenance, in addition, they do not emit polluting gases and their useful life is longer. However, they are usually more expensive.

Battery capacity for solar panels

The capacity of batteries for solar panels is measured based on the amount of energy they are capable of accumulating. A system of solar panels with batteries generates electricity that is used during daylight hours and is stored in cases of excess, to be used at night or on cloudy days. The capacity of batteries for solar panels is measured in Ampere-hours (Ah) and is calculated by multiplying the voltage by the amperage of these accumulators. The factors that influence the charging capacity of the batteries are: the amperage, the voltage and the rate of discharge of the batteries —keep in mind that the higher the rate of discharge, the lower the power supplied by the battery—.

Solar battery problems

The problem of wear and loss of capacity of batteries is one of the most common. These system elements typically have a useful life of 5 to 15 years, depending on the model and usage. Therefore, it is necessary to replace them at least once throughout the useful life of the solar panels, in which case the useful life is usually 25 to 30 years. Many times, the problem of battery wear can be due to incorrect use of them, having been subjected to deep discharges, without respecting the manufacturers’ recommendations.

On some occasions, when moving from a solar network installation to a system of solar panels with batteries, the inverter may fail —as it is possible that the model in question is not compatible with this type of installation—. If you are thinking of making a solar installation on the grid, but you are not sure if you will later switch to a solar installation with batteries, then it is recommended that you opt for an inverter that is compatible with grid injection and connection to batteries. This will save you future problems with solar batteries.