Solar batteries are a wise investment in energy storage. Without the battery pack, you will not be able to store the energy generated by the system for later use. If you are connected to the grid, then when the utility grid fails, no battery means no backup power. If you live off the grid, your system will not work at all. The battery is essential to keep the system running. Choosing the best battery for solar system involves many determinants, including battery capacity, power, efficiency, and cost, depending on your needs. To help you make the right choice, let’s review how solar batteries work and the different types of batteries available

How do solar batteries work?

When installing solar batteries in a solar panel system, you can store excess solar energy instead of sending it back to the grid. If your panel generates more power than you need, the power can be reused to charge the battery.

When your solar panels are not generating electricity, you can use the stored energy when you need it. Power is sent back to the grid only when the battery is fully charged, or only taken from the grid when the battery is low.

What are the different types of batteries?

Batteries used for energy storage are usually made of lead acid or lithium ion. When choosing the best battery for solar system, it is important to understand the difference between deep cycle batteries and flooded lead-acid batteries, sealed lead-acid batteries, and lithium batteries before making a choice. The following are some of the differences between lead-acid batteries and lithium-ion batteries:

Flooded lead-acid battery

Flooded lead acid (FLA) batteries have been in use for 150 years and are one of the most commonly used batteries for off-grid solar installations. These batteries are cheap, 99% recyclable, and easy to discard at the end of their useful life.
If you are looking for an affordable option but with the following hands-on monitoring features, these are the best solar batteries:
-Flooded lead-acid batteries are designed to handle daily charging cycles. They do emit gas as a by-product, so they must be properly ventilated.
-FLA batteries are very suitable for people who like to operate the system themselves. They are the most affordable option, but require occasional maintenance to work properly.
-These batteries require regular maintenance. The plates of each battery in the battery must be immersed in water to work properly (this is why they are called “soaked” batteries). You need to add water every 1 to 3 months to keep the dishes submerged. It is wise to check once a month.

Sealed lead-acid battery

If you cannot check regularly, the best battery for solar system is a sealed lead-acid battery, which has the following advantages:
-These batteries are splash-proof and non-hazardous. There are two sealed lead-acid batteries with fairly similar characteristics: AGM (absorbent glass mat) and gel.
-The sealed battery is an independent system. They do not need to be refilled with water like a battery filled with water. For this reason, they work well in places where there is no full-time job, such as the off-grid holiday cottages you visit once or twice a year.
-Sealed batteries are more suitable for handling temperature. If they are left unused for a long time when you are away, they will not self-discharge quickly.

Lithium battery

Lithium batteries are a relatively new technology that was put on the market in the 1970s. They are common in laptops and mobile phones, but recently they have become more and more popular in the field of renewable energy. Lithium batteries are more expensive, but there are several benefits that justify the higher price tag:
• Longer service life
• No maintenance
• More efficient use of electricity
• More available storage capacity (deeper discharge)
• No exhaust/ventilation

How do I compare solar batteries?

When considering solar cell options, you need to compare each type of battery based on capacity, depth of discharge (DoD), round-trip efficiency, and battery life to find the most suitable solar cell based on system requirements. Be sure to check the following:

Capacity: The capacity is the total amount of electricity that the solar cell can store. The power is measured in kilowatt hours (kWh).

Depth of Discharge (DoD): Depth of Discharge (DoD) indicates the used battery capacity. The higher the DoD, the more usage you get from the battery capacity. Your depth of discharge should usually be at least 40% or higher.

Round-trip efficiency: The round-trip efficiency is the difference between the energy used for charging and the available energy. Higher round-trip efficiency is generally more economical. You should look for a round-trip efficiency of about 80%.

Battery life and warranty: As the battery performance will decline over time, the warranty can guarantee good performance for many years or cycles and ensure that the battery maintains a certain capacity.

How to choose the best battery for solar system?

No matter what kind of off-grid system you are looking for, your battery pack is a key component. Choosing the right battery depends on many factors, such as application, budget, and maintenance expectations (such as regular maintenance and replacement intervals). Your living conditions will determine the best battery choice for your project.

When it comes down to it, you need to choose the best battery for solar system, whether it is AGM, gel, lithium-ion battery or basic flood lead-acid model. Before you make any type of purchase, please refer to our section on solar cell types and our section on main considerations to remember before buying. You don’t want to ignore this important comparison, because different battery types and functions can make a big difference when meeting your needs. Remember, when making a decision; always consider your budget and main application. The most important thing is to stay safe; if you do not know what you are doing, you should always seek professional help.