Batteries for solar panels are one of the most important elements we can find when carrying out an isolated photovoltaic solar installation in the Philippines. They provide us with power even when the solar panels are not generating power—when the sky is cloudy or at night. They will allow us to reduce the expenses of our electricity bill further.

I will explain what types of batteries we can find and the best batteries for solar panels in the Philippines. If you want to get the most out of your photovoltaic solar installation, I recommend reading the article.

What are batteries for solar panels?

Batteries for solar panels are energy accumulators that allow the electricity generated in solar panels to be stored. These offer us the possibility of completely disconnecting from the electrical network, so we will not have to pay any extra cost. These are essential elements of isolated photovoltaic solar installations in which it is necessary to have a source of electricity when working without light.

Types of batteries for solar panels

We can find several types of solar batteries, depending on the materials with which they have been manufactured —such as gel batteries for solar panels and lithium batteries for solar panels—as well as their operation and purpose. These are the main models.

Monoblock batteries for solar panels
This type of battery has 3 or 6 internal cells of 2V each. Depending on the model, they are connected, forming a single 6V and 12V block. Monoblock battery cells are made of lead and electrolytes.

These, through redox reactions in which electrons are transferred between different reagents —modifying oxidation, allow energy to be stored and generated. These batteries are intended for small installations, such as lighting, household appliances, or the computer. The models are also cheaper than the rest. There are several types of monoblock batteries. These are:

Open lead acid monoblock batteries
They are the most economical. Depending on the model, they have an average of 400 complete charge and discharge cycles with a useful life of 2 to 3 years. They can withstand discharge depths of up to 20%.

Deep cycle monoblock batteries
These are models very similar to the previous ones, although they are reinforced to withstand discharge depths of up to 80%. The useful life of these batteries is usually 7 to 8 years.

AGM monoblock batteries: Or AGM batteries for solar panels.
They are batteries that are sealed and do not require maintenance. The best batteries for AGM solar panels can reach up to 7,000 charge cycles.

Monoblock gel batteries or gel batteries for monoblock solar panels.
They are very similar to AGM batteries for solar panels. The difference is that these have a better response to voltage against discharge.

Lithium-ion monoblock batteries or lithium batteries for solar panels.
These are the best batteries for solar panels. These lithium batteries for solar panels can withstand discharges of up to 80% without damage.

Stationary batteries for solar panels

These batteries have a longer useful life than monoblocks, with an average of 20 years — depending on their use. As their name suggests, these batteries are recommended for regular use in permanent solar installations and for medium or high consumption. We can distinguish two types of stationary batteries. These are:

Stationary open lead acid batteries
These are batteries made up of six individual and separate compartments but connected. These are found inside a polypropylene structure that works as an insulating material and is resistant to the acid generated by each cell. The average life of these batteries is 15 years. They respond well to deep discharges, with little escape of gases and little maintenance.

Stationary gel batteries or gel batteries for solar panels.
These work in medium and high consumption when the discharge depth is moderate. They have a long lifespan.

How much do batteries for solar panels cost?

The different types of batteries and their various models and brands mean that not all are worth the same. Its price will differ depending on the brand, model, and battery capacity. In the following table, we can see the price range for each type:

Solar Battery Type Philippines	Solar Battery Price Philippines
Monoblock Batteries	30k PHP to 60 PHP
AGM Batteries	12k PHP to 120k PHP
Stationary Batteries	12k to 425k PHP
Lithium Batteries	30k to 607k PHP

What battery to choose for solar panels in the Philippines

The best batteries for solar panels vary depending on the use they will be given —in permanent solar installations or for occasional use— and what we want them for —installation of an isolated home, solar pumping installation, or vans—.These are some of the best models on the market:

1. LG Chem Resu 10H lithium battery

It is a straightforward and comfortable battery to use. This can be installed on the wall or directly on the ground. It offers a total of 9.8 kWh. Its capacity in amperes is 63, and the voltage range ranges from 350-450 and 385-550. Its maximum power is 5.0 kW, and the peak power is 7.0 kW. It has a useful life of 10 years and approximately 6,000 charging cycles. This battery is compatible with most brands on the market.

2. Sigma 6 OPzS 800 1256Ah (C100) Battery

This battery stands out for its long functional life of 15 years and ability to withstand charge cycles. It is a battery that hardly needs maintenance due to its low antimony content and the large reserve of electrolytes. This battery includes six pieces of 2V for 12V power. You can add 12 more 2V pieces to get 45V sets. This battery stands out for its discharge capacity 893Ah (in C10) and 1256Ah (in C100).

3. Pylontech US3000 45V lithium battery 3.5kWh

This is one of the best lithium batteries for solar panels. This model allows deep downloads, up to 80%, without suffering. It has a duration of 6,000 cycles and a maximum charge and discharge intensity of 37 amps, 1776W per battery. In addition, it can be mounted in parallel with a maximum of 8 batteries. Although it can work at a maximum intensity of 74 3552W, its recommended use is for 37 amps of maximum intensity —as the manufacturer indicates.

4. Hoppecke 7 OPzS 490 12V 735Ah battery in C100

This battery has 6 2V accumulators that allow a total of 8820W. The discharge capacity of this battery in 10 hours (C10) is 468Ah, and in 100 hours (C100) it is 630Ah. This holds up to 20%, extending its useful life to 20 years and about 8,000 cycles.

It is recommended not to exceed 50% (for 1,500 cycles) in more intensive uses. This battery works at a recommended voltage of 12V. Its maintenance, on the other hand, is simple. This should be done with distilled water in case the maximum and minimum levels of the electrolytes are below the marks. It is a powerful battery, ideal for solar installations.

The factors that influence the amount of energy that a solar battery can accumulate are:

Amperage -The electric charge passes through the conductor every second. In other words, it is the intensity of electrical current provided by the solar battery.

Voltage – It is the electrical voltage of the circuit. That is the force with which the current supplied by the battery circulates.

Download speed – It is the time it takes for the battery to discharge, starting from a full charge. The higher the battery’s discharge rate, the less power it can offer. In most cases, it is not recommended to download them more than 50%. Depending on the voltage of the battery, it can supply us with one amount or another of energy and power:

12V (volt) solar batteries – For monthly consumption of less than 100kWh (kilowatt hours) and powers of 1kW (kilowatts).

24V solar batteries – For monthly consumption between 100kWh and 150kWh and powers between 1kWh and 5kWh.

48V solar batteries – For monthly consumption over 150kWh and power over 5kW.

Where to buy solar batteries in the Philippines

The company that installs the solar panel system will be in charge of selecting the battery that best suits the characteristics of our installation. However, there are many stores (physical and online) where it is possible to buy batteries on our own such as Shopee.

When are solar batteries necessary?

They are essential in isolated photovoltaic installations since there will be no electricity available without them when the solar panels do not produce electricity.

Suppose the installation is connected to the electrical network. In that case, they are not essential, although having accumulators will allow us to be more energy self-sufficient and reduce the cost of electricity bills.

How do solar batteries work?

These solar batteries are essential to a self-consumption system that allows solar energy consumption after generation. Like any energy accumulator, they are devices where the solar energy generated by the photovoltaic system is stored.

These accumulators are charged during the hours of photovoltaic production. They make this energy available in the hours when the sun does not shine or when it is more convenient to consume their energy instead of supplying it from the electrical network. The connection between the photovoltaic modules and the batteries for solar panels is made through the solar inverter, the brain of the installation, or through a charge regulator. Later we will talk about the compatibility between these two devices.

How to choose the best solar batteries for a home?

The choice of batteries for a solar panel system for self-consumption depends on the home’s energy consumption and the photovoltaic installation’s size. Let’s say we have a house with a consumption of 6000 kWh/year that has an installation of 10 380W panels.

Installing a 5 kW power battery (5 kWh of energy) is recommended. If the installation is 14 380W panels, a 10 kW power battery (10 kWh of energy) is recommended. It is common practice to oversize the system concerning the battery charging power to be able to charge and self-consume simultaneously.

As a basic rule, we usually look for a battery that helps us store as much energy as we need until the next day. This does not imply that we will always have energy in the battery, but it helps to balance the investment and profitability of the photovoltaic system when choosing its capacity.

How many batteries for solar energy do you need in your house?

The amount of solar battery you need depends on your purpose. If your goal is to reduce by 100% the amount of energy you use from the electrical grid, but without disconnecting from the grid, the simple calculation is as follows:

An average house typically consumes 16 kWh /day, 70% of which is consumed in the late afternoon and at night (of course, if you have a large house with a pool, etc., consumption will be higher).

This way, we can assume that this house will need to buy 70% of its energy from the grid, approximately 11.2kWh per day. In this case, Tesla’s Powerwall 2 would do the job as it has a capacity of 13.5kWh.

Pragmatically, it is impossible to dimension the amount of solar energy batteries needed without a detailed understanding of their energy consumption profile. This means you need a good energy monitor in your home with suitable data as a first step. So a good installer can use their software to show you exactly the optimal number of batteries and solar panels for your home.

Solar batteries and the savings generated

Batteries make the price of a photovoltaic system more expensive. Therefore, its profitability is lower than in the case of systems without accumulators. However, a system with integrated batteries offers more significant savings on the electricity bill. The battery is the best option for those looking for maximum savings on their electricity bill.

If we think of an average system, less than 4 kW installed, with a 5 kWh battery, it can self-consume up to 85% of the energy produced, thus discharging less to the electrical network.

This can reduce the electricity bill by up to 80% since the kWh purchased from the electricity network is much more expensive than the kWh sold, around 3PHP.

In addition, in the context of electricity tariffs with 3 sections of hourly discrimination, the battery is beneficial between 7:00 p.m. and 10:00 p.m.

Between these hours, photovoltaic production is low, especially in winter, since it gets dark early. Even in the summer, it is low due to low solar irradiation. In addition, between 6:00 p.m. and 10:00 p.m., the price of the kWh skyrockets, being the most expensive time slot of the day, rush hour.

Where do you usually use a solar battery for

1. In homes connected to the electricity grid, the batteries will save 70%-90% on the electricity bill. Still, the initial investment will be much higher than an installation without batteries or accumulators.

2. In isolated houses, the investment will also be higher, but energy will be available 24 hours a day.

3. In motorhomes with solar panels, batteries are recommended when there is no network connection at the camping site.

4. In any case, it is necessary to study the particularities of each installation to determine whether batteries are necessary.

What is the ROI on a solar panel system with batteries

Including batteries in a solar panel system makes the initial investment more expensive. However, it is estimated that 40% of daily energy consumption is carried out in the hours when there is no sun, so the profitability of your solar panels will be greater.

In an installation connected to the network without batteries, the return on investment is estimated to be between 7 and 9 years, which can be reduced to 3-4 years if we benefit from the available aid and subsidies.

In the case of installations with batteries, the investment is more significant, but so is the profitability. This is because the level of self-consumption would range between 85% and 100%, meaning a return on investment in 10-12 years (5 to 7 years with subsidies).

Suppose we have contracted a rate with hourly discrimination in three sections (peak, valley, flat). In that case, we can ensure that consumption from the electricity network is focused solely on the hours when electricity is cheaper.

What to consider when buying solar batteries?

To obtain the battery that best suits our energy needs, we must compare various manufacturers and models, taking into account the following aspects:

The amperage – The battery’s capacity adapts to the time of use we need.

The power it can supply – We need the battery to cover our energy demand.

The years of useful life and the number of charging cycles – To calculate the time it will take to replace the battery.

Choosing the ideal battery for our solar installation will also depend on energy consumption and the size of the installation. It is common to install more panels than we would need in case of not having batteries. In this way, we can consume the energy we generate while storing the surplus. 

Conclusion

Having batteries for solar panels has its advantages and disadvantages. The main advantage is the disconnection from the electrical network. Many homes want to be energy-independent; in other cases, they are homes in isolated areas where connecting to the grid can be more complicated. However, this carries a significant risk if days go by without sun, leaving the house without light in the 19th century.

On the other hand, a system with batteries is more expensive than one without them, and it must be considered that solar modules have a longer useful life than batteries. Also, some of them need maintenance.