Harness Power


Posted On: November 13, 2020

Choosing The Best Solar Power Battery Bank

Solar power battery bank

The demand for renewable clean energy is continually growing. As more individuals and businesses gravitate towards sustainable energy solutions, the search for reliable energy storage naturally follows. Solar is an incredible energy resource with little to no carbon footprint, but it does have one flaw: the sun has to go down. Therefore, maintaining energy backup through a solar power battery bank is an imperative part of any renewable energy system.

While it’s true that we can’t generate solar power at night, we can use solar power that has been stored throughout the day. Solar panels convert power generated by the sun’s rays and store the energy in solar battery banks for later use.

Keep reading to learn more about solar power battery banks and how they could help you store more solar energy.

What Is Battery Backup Using Solar Power Battery Banks?

America’s power grid is becoming increasingly strained by the demands of modern society. Thankfully, there are solutions. Many property owners have turned to generators as a means of maintaining power during increasing outages. However, generators are not a renewable energy source.

Battery banks offer a unique storage solution for our nation as we continue to turn towards clean and renewable energy resources. These banks are connected directly to your solar system for daily recharging and continuous storage of power. In some cases, solar power battery banks also offer property owners reduced energy rates from local providers during peak electricity hours.

A solar power battery bank contains either a single battery or multiple connected batteries wired to work as one large battery. Battery banks combine with your solar power system to help provide power 24/7.

Before you choose a solar power bank, it’s helpful to know more about the options available to you. Keep reading to discover the many different types of solar batteries as well as their advantages and disadvantages.

Solar Power Battery Options

Solar power batteries make it possible to store electricity during the day and make it available when you need it the most. Li-Ion batteries, also known as lithium-ion batteries, have been the top choice for solar power storage for years.

As demand and incentives for solar power grow, more battery storage options are being explored and innovation is happening. Here are the current types of batteries that work with a solar power system:

Lithium-Ion Batteries

Lithium excels at driving electrons and generating electricity efficiently, making lithium-ion batteries one of the best solar power battery storage options to date. There are some concerns about the flammable fluids inside Li-Ion batteries, the rising costs of “white petroleum” used in the batteries, and the cobalt inside which may be a conflict mineral. Still, these batteries are the most widely-used in conjunction with Solar Power Systems installed Nationwide today.

Flooded Lead Acid (FLA) Batteries

Flooded Lead Acid batteries, also known as “wet cells”, Flooded Lead Acid batteries are commonly used in solar energy systems. While these batteries are known for their affordability and wide range of sizes, they do come with some downsides. FLA batteries can take up lots of space, and require regular maintenance. They work by generating hydrogen and oxygen gasses during recharging – which can pose a safety hazard to the surrounding environment. FLA battery system must be consistently monitored and maintenanced by replacing the expelled gasses with distilled water as needed.

With those downsides in mind, FLA batteries are not typically a good choice for powering a home or large building. Plus, they need to be replaced every seven years.

Absorbent Glass Mat (AGM) Batteries

Absorbent Glass Mat batteries give off more power than FLA batteries, but they still take up a considerable amount of space. While AGM batteries are heavy and generally more expensive, they require little to no maintenance. FLA batteries require constant monitoring because of hydrogen loss, but AGM batteries require no maintenance after initial setup. They have been an alternative option for power storage for the last several years. Read this direct comparison between AGM and FLA for a better understanding of the pros and cons of each battery type.

Saltwater Batteries

This innovative new battery technology is saltwater based, making it safer and more sustainable than many other types of batteries used with solar power. These batteries rely on saltwater electrolytes for power, which makes them free from heavy metals and recyclable. However, they are very new and largely untested for home use.

Going Off-Grid With A Solar Power Battery Bank

A solar power battery bank is an essential component of any off-grid power system.

You will need enough battery storage for year-round power. After all, you don’t want to suffer a power outage one winter night because your battery bank didn’t store enough charge during the warmer months.

It’s equally important to be sure your battery bank isn’t way too large. Too much battery storage can prevent your system from fully recharging, which will ruin your batteries over time. So, it’s important to choose the right battery bank for your solar power system if you plan to be completely off-grid and self-sustaining.

Solar Power Battery Bank Options

Just as there are many different types of solar power batteries available, there are also a variety of different solar power battery banks you can choose from for storage too.

Flooded Lead Acid (FLA)

Flooded lead-acid batteries (FLA batteries for short) have been used for solar power battery banks for years. They are built with lead plates submerged in an electrolyte mix. But as mentioned before, FLA batteries need to be refilled with distilled water constantly. Water evaporates via hydrogen and oxygen gasses during use, so you will need to plan to have them refilled 1 to 2 times a month.

FLA batteries have the lowest startup costs too, making them a good option for many homeowners switching to solar power systems. However, they don’t have the same capacity before recharging as some other battery types.

Sealed Lead Acid

These batteries are safer than flooded lead-acid batteries, but they come with a shorter life expectancy. In addition, they are known to have charging difficulties, which can lead to a shorter lifespan and more frequent recharging.


Lithium batteries are the ideal solar storage option for most projects. In comparison to FLA and sealed lead-acid batteries, lithium solar batteries offer faster charging, deeper discharges, better energy density, and they live longer.

Plus, lithium batteries do not require maintenance like their FLA and sealed lead-acid counterparts. They do not require ventilation either. However, they do have higher upfront costs. In the long run, lithium batteries are a better investment if you’re looking for a battery bank that is low-maintenance and long-lasting.

How Much Does a Solar Power Battery Bank Cost?

The cost of solar power battery banks varies greatly depending on the type of bank, brand, and the amount of storage you require. Flooded lead-acid banks are the least expensive, but they require regular maintenance and repairs. Therefore, while they start at under $600 for a small sealed lead acid battery bank, over time the cost will greatly multiply. A flooded lead-acid battery bank of the same size will cost just under $800, while a lithium bank of similar size costs in the thousands.

File:Shoals Battery Bank.jpeg - Wikimedia Commons

What Size Battery Bank Will I Need?

The size of solar battery bank to best fit your needs will depend on four important factors:

1. Power Usage

To determine the right size of battery bank, you will need to know how much power you will be using daily. Evaluate or measure the total power usage of all appliances operating on your system. Then, determine how long each appliance will be used every day to help you get an accurate number.

Power usage figures can be determined in a variety of ways. If you are living off-grid, your power usage estimates will be quite different from on-grid living. For example, switching electric appliances to read power labels can be a daunting task.

If you will be operating your system on-grid, you can first seek out the daily average from your annual electric bill to determine accurate power usage estimates. Next, check your power meter for more information about your power usage. You can use a Watt meter to get accurate power usage numbers before deciding which solar power battery bank to purchase.

Determining power usage estimates for off-grid systems is more complicated. You can estimate power usage by consulting the labels on your appliances as well as using online solar power battery bank calculators.

2. Days of Autonomy

How many hours or days will you need your solar power battery bank to provide energy between charging? That number is the days of autonomy you will need from your battery bank. If you anticipate going several days with heavy cloud cover, your solar panels may not be able to charge your batteries much, so you will need to draw power from your solar power battery bank.

3. Depth of Discharge

Before choosing a solar power battery bank, you will also want to consider the depth of discharge. A battery cycle begins when a fully charged battery is discharged and then restored to full power. The depth of discharge is the amount of energy that can be discharged safely from a battery.

Most deep cycle batteries should never be discharged to less than 50% before recharging. However, lithium-ion batteries can only be discharged to 80% before recharging. This is so that you can’t use all of the energy stored in your solar power batteries without damaging them.

4. System Voltage

You will need to know your solar system voltage to choose the right size for your solar power battery bank. Most systems are 12 volts, 24 volts, or 48 volts. Typically, higher voltage batteries provide a cost advantage because the increased energy output reduces cost for wiring the system.

Contact Us Today

Understanding all these factors can take time, but it’s well worth learning more about your solar system to make the right choices for a clean and sustainable energy future. The quickest way to learn is through consulting with someone who is already an expert. If you have any questions about adding a solar power battery bank to your solar system, contact our experts at Harness Power today.






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