Best Batteries Review for Solar – Buying Guide


Batteries are widely used in the photovoltaic sector, although they are also in high demand in many other sectors for different uses, such as: Batteries for caravans , Batteries for wheelchairs , industrial batteries, Batteries for alarms or batteries for emergency lighting, among others. .

At AutoSolar we offer the highest quality batteries that best adapt to the varied needs of our customers, as we have a wide variety and the most competitive prices on the market.

Information about Batteries

device capable of storing energy in the form of chemical energy and subsequently, using electrochemical procedures, producing electrical energy is called a battery or electric accumulator . In photovoltaic batteries this cycle can be repeated for a certain number of times , for example, deep cycle batteries can repeat it many times.

solar battery or accumulator is a secondary electric generator, that is, it cannot work without having been previously supplied with electricity through the so-called ‘charging process’.

The operating principle of batteries is based on the chemical process of reduction-oxidation (redox), in which one of the components is oxidized (loses electrons) and the other is reduced (gains electrons). The parameters of a battery are voltage, current, charge capacity, electrical capacity, energy, resistance, mass, performance, charge / discharge constant, and memory effect.

Solar batteries or accumulators undergo a chemical process that releases and generates energy, so their use reduces their useful life.

Battery Types

AutoSolar offers you the best products on the market at the best price. As for voltage, we 6V batteries , battery 12V , 24V battery , battery 48V . And in terms of technology we have: Lead Acid batteries, AGM batteries, GEL batteries, Monoblock batteries, OpzS accumulators or OpzS batteries. In addition, we have battery monitors, so that your work is controlled at all times. Depending on each type of solar battery, its use should be one or the other, and it has its advantages and disadvantages, which we explain to you in the specific sections of the AutoSolar website.

In general terms there are different types of solar accumulators:

– Starter batteries or SLI batteries: for ignition sources, vehicle lighting such as internal combustion engines.

– Industrial batteries for the telecommunications sector, auxiliary services, energy transformers (solar and wind), UPS, emergency lighting and electric vehicles, among their most frequent uses. Industrial batteries are divided into:

– GEL batteries .

– AGM batteries .

– Lithium battery .

– Stationary batteries that are divided into:

– Stationary OPzS Batteries

– Stationary OpzV ​​Batteries

– Stationary Batteries TOPzS

What information to consider when selecting a battery

To correctly select a battery, you must choose the type of plate (which can be flat or tubular) and the construction or its internal technology (which can be liquid or immobilized electrolyte), as well as size, that is, determine both the number of cells as the capacity of them.

To correctly choose the solar battery you must take into account:

– The application to determine if a monoblock battery is required , an open lead acid battery or a stationary battery is preferable .

– The physical location to see if it will or will not perform periodic maintenance, so you must choose between lead acid batteries open , batteries GEL , AGM batteries , lithium or stationary batteries .

– The environmental conditions , to determine the temperature and ventilation available, taking into account that monoblock batteries do not emit gases or require maintenance, which includes: GEL batteries, AGM batteries, lithium batteries and OpzV ​​stationary batteries.

– The physical characteristics of the battery , to know if there is space with the necessary requirements so that it can be installed without problems and its operation is in accordance with what is established by the manufacturer.

– Recharging , that is, that the recharging conditions are optimal.

What information should be taken into account to size a battery

The points to take into account for the correct sizing of the battery are determined below:

– Nominal voltage and voltage limits compatible with the equipment or power supply system.

– Discharge current or power .

– Duration of discharge current or power .

– Average temperature of where the battery is to be installed.

What factors determine the nominal capacity of a battery

The normal capacity of a battery depends on three different factors :

– Discharge rate , or speed at which the battery discharges.

– Temperature where the battery is installed, which is usually 20ºC.

– Final tension .

What is a battery cycle

It is the succession of a discharge followed by its subsequent recharge until the extracted energy is completely recovered.

The depth of discharge of a battery is the ratio of the discharged capacity to the nominal capacity of the battery. The greater the depth of discharge, the fewer the number of cycles that the battery can deliver.

How does temperature influence operation?

High temperatures accelerate the corrosion of battery grids and the degradation of active materials while their performance is significantly increased.

When batteries experience low temperatures, the ability to deliver current decreases but the life of the batteries increases . This is because all internal corrosion processes slow down.

Approximately for every 10ºC increase in ambient temperature above the reference temperature, the service life is reduced by half. That is, a five-year battery life at 25ºC will only last 30 months if the ambient temperature is 35ºC.

How the shelf life is estimated

The useful life of a solar accumulator is the operating time that the manufacturer predicts if the specified conditions are maintained. In some cases, the time has been extrapolated from the data obtained in a so-called “accelerated life” test, in which the battery is tested at a high temperature (for example, 70ºC) until it reaches 80% of its capacity. . The time obtained (eg 6 months) is then converted to nominal operating conditions of 20ºC (in Europe) or 25ºC (in the USA).

To guarantee safety during operation, the standards recommended by the manufacturer based on its internal technology must be taken into account, for example, GEL batteries or AGM batteries do not require maintenance and can be installed in a place without ventilation. While OpzS Stationary batteries or open lead acid batteries require periodic checks of the acid levels inside them and must be topped up if necessary, they must also be installed in a ventilated place because they can emit gases during their operation. functioning.

To guarantee the useful life established by the manufacturer, its instructions must be followed in all cases.

In what current regime is a battery recharged

Usually recharging is carried out at 10% of the nominal capacity, as it is recommended to do so at less than 5% and not more than 20%.

At what voltage can a solar battery be discharged

The batteries must be discharged in times between 3 and 20 hours, and at the value of 1.75VPC.

For 12V batteries it is 10.5V, but the product manual should be consulted because it may be a lower value (for example 1.67VPC) if the discharge is in 15 minutes, or 1.9V if the discharge is in 100h.

How to know if a battery is well charged

It depends on the density of the electrolyte. If the density of the electrolyte is known (expressed in Kg / l) adding the coefficient 0.845 we will obtain the open circuit or no-load voltage (per cell) of that battery.

Example: The electrolyte density of sealed batteries is 1.3 Kg / l. Therefore, 1.3 + 0.845 = 2.145. This will be the value in Volt of the open circuit voltage. If it is a 12V monoblock battery (6 cells), the open circuit voltage that we will measure, when it is well charged, will be 12.87V.

All AutoSolar batteries have a manufacturer’s warranty except those for loose cups.

Battery Maintenance

The batteries must be installed on a flat surface where it is not exposed to high temperatures or direct sunlight, as during its operation the temperature increases significantly and can seriously affect it.

Respecting the applications of use, the charging parameters and the maintenance and use of the battery makes it last as long as the manufacturer estimates. If this does not happen, the useful life is usually drastically reduced.

Any accelerated degradation that drastically shortens life cycles or misapplication will not be covered by the manufacturer’s warranty. To optimize the useful life it is recommended that the battery is always above 70% charge.

How to select the correct battery voltage based on energy consumption

An important part to be able to size our installation well is to select the battery voltage well so that the useful life is lengthened as much as possible.

The calculation of the correct voltage of the batteries must be carried out according to the energy consumption of the house, taking the consumption of the house with the Wh it consumes per day, and thus make a test to check what will be the correct voltage for our photovoltaic installation.

For example, having consumption of about 3200 Wh / day, we are testing with the different possible voltages.

These 3200Wh / day are divided by the voltage that is required and then the result must be multiplied by 2 so that the battery does not discharge more than half. The result obtained must be multiplied again by 2 to obtain the value corresponding to 2 days of autonomy .

For a 12 volt system : 3200/12 = 266.67 x 2 = 533.33 x 2 = 1066.67 Ah

Given this, we realize that we get a very high battery capacity.

For a 24V system : 3200/24 ​​= 133.33 x 2 = 266.66 x 2 = 533.33 Ah

This capacity for an installation of these characteristics we see a corresponding battery capacity.

For a 48V system : 3200/48 = 66.67 x 2 = 133.33 x 2 = 266.66 Ah

In this last option, even if the capacity of the batteries is reduced, it may even be too much since with the 24V system we can work well and the necessary investment will be reduced.

Analyzing these points with consumptions such as those that have been raised, the 12V option will only be selected if it is really necessary if the consumptions work at this voltage. The most suitable option for this 3200 Wh / day installation is a battery voltage of 24V, since that of 48V is too much, although it would be interesting if an extension of the installation is planned.

Most common sectors where batteries are used

AutoSolar batteries are characterized by their versatility, although the sectors in which they are most commonly used are: for the solar sector or the photovoltaic sector, for specific industrial machinery, for mobility and transport , such as batteries for wheelchairs, batteries for multiple types of alarms or for emergency lighting. Motorhome batteries are also in high demand .

If you require photovoltaic batteries and would like to know if our offer of batteries can be adapted to what you need, contact us, or send us an email to and we will solve all the doubts you may have in this regard.

AutoSolar’s battery price is the most competitive on the market, as we are unique in offering a manufacturer’s warranty with a wide variety and a very fast delivery time.

Battery connection

The batteries, where they are located, can be connected in parallel or in series, although the parallel connection is not recommended or covered by the warranty.

Battery Installation

If you want the AutoSolar installers to carry out the installation together with the purchase of batteries , we leave this option at your disposal, since our installation technicians can travel to any point of the peninsula to carry it out. This is intended to provide a comprehensive service of: advice more in line with your needs, always offering price and characteristics alternatives, sale with payment facilities and from anywhere in the world, prompt and punctual transport and installation anywhere on the peninsula. Do not hesitate and check the most competitive prices on the market , we are at your disposal

If you have any questions regarding the choice of which is the right battery for your needs, or ask us at 96 143 01 13 or via We guarantee you the best price with our wide variety of cheap batteries .

Contact us and enjoy the best price on the market.

Configuration of the charging stages of the different battery models (Lead-Acid, AGM and GEL)

Next we are going to show the standardized charging voltages of the different charging phases of the different battery models. The charging voltages can be found in the technical sheets depending on the manufacturer and the battery technology, it is advisable to always check these charging voltages to ensure correct operation. Charging batteries with incorrect voltages leads to a rapid loss of useful life, it is very important to reach 100% charge and never overcharge the battery, for this we must adjust the different charging stages depending on the type of technology .

As can be seen in the table, the AGM and GEL battery models do not have the equalization charge stage.


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