How Long Do Solar Batteries Last? (2025 Lifespan Guide)

As the appetite for cleaner and more affordable energy increases, the question of the type of battery becomes a crucial one. Imagine your batteries die out before the expected time. Frustrating, right? That’s why knowing the right battery that lasts longer, before you buy one, is crucial.

Now, lithium-ion batteries have just occupied almost the entire solar market. About 70% of the global solar battery market share is staggering! What influences it? It’s the long lifespan. Lasting about 10-15 years! It simply goes beyond the lead-acid batteries in consumer choice. 

While it doesn’t stop there! Better technology, like flow batteries, is taking up the solar battery market because of the longer lifespan it offers. Let’s discuss the different types of batteries and how long they can last. H2: Understanding Solar Battery Lifespan

Solar batteries do not end suddenly. It’s a gradual process. Over time, the battery degrades and its efficiency decreases, making it unusable. This usually occurs when the solar battery reaches 80% of its entire capacity. 

Moreover, there is a typical number of cycles your battery charges and discharges. After the average number of cycles, your battery is more likely to become unusable. Thus, the battery takes more time to charge and discharges quickly. A clear indication that your battery is marking the end of its lifetime. U.S. Department of Energy

How Long Does a Solar Battery Last

The most common consumer question is, “How many years does the solar battery last?” The answer depends on the type of battery. Well, nowadays, lithium-ion batteries have taken most of the market share. Lithium-ion batteries last about 10-15 years. It usually takes them about 3000 to 7000 cycles of charging and discharging to finally reach its end of their life.

Lead-acid batteries, on the other hand, generally last after 500 to 100 cycles, making a maximum of 3 to 7 years. This is far less than lithium-ion batteries, which offer lucrative return on investment and top-notch value for your solar system.

The last and most important is the flow batteries. Being new in the market, it won’t take much time to dominate. These batteries last considerably longer. Potentially more than 20 years, leaving behind lithium-ion and lead-acid batteries by far. This makes up lifecycles to be 7000 to 10,000+ cycles.

How a Solar Battery Lifespan Is Calculated

Thinking about how you would track the longevity of your solar batteries? Well, calculating your solar battery is not a big deal. You can calculate the lifespan of the batteries by monitoring the total cycles it has performed before their performance drops.

One cycle means that your battery charges during the day and then the power is used up at night. This completes one cycle. The maximum cycle a solar battery can perform before its efficiency reduces to 70 – 80% is how you measure your battery’s lifespan. 

For example, a lithium-ion battery with a capacity of 5 kilowatt-hour can power through nearly 7000 full life cycles. After the life cycles are completed, the battery will be able to generate only 4 kilowatt hours of energy.

Well, you can maximize your battery lifespan by following the manufacturer’s guidelines for optimal performance. Keeping it away from high temperatures and performing regular maintenance play a key role. This is how you can increase the lifespan of your battery at its peak.

Type of Battery LifeSpan

When talking about solar batteries, there are two main types of lifespans. One is the warranted life, while the other is the useful life of a solar battery. Both of these solar battery’s life indicate the guaranteed period and the potential period of the solar batteries’ life. Let’s have an overview of the different life stages of the lifespan of solar batteries.

Useful Life: 

Also called end of life (EOL), is the time when the solar batteries usually degrade to 70-80% of their actual performance. The solar battery’s life doesn’t end suddenly. Their performance slowly diminishes with time. This slow degradation is called ‘capacity fade’. 

Solar batteries don’t stop working at the end of life. However, it becomes unusable for the actual purpose it was intended to perform.

Warranted Life: 

This is the manufacturer’s assured life for a solar battery. This guaranteed life can vary depending on the type of battery and manufacturer. Typically, this lifetime is for about 10 years. Sometimes, the guaranteed life is based on the maximum number of cycles the solar battery can perform before the end of its useful life. 

It doesn’t necessarily mean your battery will reach its end of life after the warranted life. However, an average time period is provided by the manufacturer for the lifespan of the battery to end. Well, sometimes this guaranteed life is based on the total energy throughput. 

Energy throughput is the total energy the battery can deliver over its lifespan. The battery performance may fade away when the total energy throughput limit is reached.

Annual Battery Degradation: 

You need to keep this thing in mind that your battery degrades over the years. On average, your battery might degrade 1-3% annually. That’s such a trouble! However, make sure to follow the manufacturer’s usage guidelines. This is how you achieve the maximum of the battery’s maximum performance and longevity.

Dead Battery: This happens when your solar battery capacity reaches about 40% of its original capacity. The battery no longer delivers, effective, reliable, and required energy for long-term usage.

Here’s a complete breakdown of a solar battery’s original lifespan vis a vis its warranted lifespan:

Factors That Affect Solar Battery Longevity

Your battery’s lifespan isn’t just dependent on time. Certain key factors like the type of battery, the conditions you keep it in, the temperature coefficient, and more play a crucial role. IT doesn’t just stop there! The way you keep and maintain your battery also affects its capacity over time.

Let’s dig into those aspects that affect your solar battery longevity.

1. Type of Battery

There are several types of batteries, each with a different lifespan as discussed before. Here is a further subdivision of several types of batteries and the life period they could function in optimal conditions.

Lead-Acid Batteries: 

Flooded Lead-Acid Batteries: Flooded lead-acid batteries are the oldest, yet most commonly used type. These involve electrodes or plates submerged in electrolytes. They require regular topping with distilled water to maintain the required performance. They require regular maintenance and can go up to 3-5 years in optimal conditions.

Sealed Lead-acid Batteries: Also called valve-regulated lead-acid (VRLA), these use sulphuric acid as electrolyte and are sealed so that the electrolyte doesn’t spill out. Compared to flooded lead-acid batteries, they require no maintenance, and they can last up to 4-8 years.

lithium-ion Batteries

These are the most commonly used batteries for residential and commercial purposes. LFP batteries use lithium ions that circulate between negative and positive electrodes. This is how it stores and releases energy for use.

Lithium Iron Phosphate (LiFePO4): These batteries use iron phosphate as the cathode and can last up to 10 to 15 years.

Lithium Nickel Manganese Cobalt (NMC) Batteries: These batteries also consist of lithium ions flowing from cathode to anode and vice versa for charging and discharging. However, NMC batteries use a blend of nickel, manganese, and cobalt as the cathode. NMC batteries have a lifespan of 10-12 years.

Salt Water Batteries

Saltwater batteries, on the other hand, use sodium instead of lithium ions as charge carriers. Moreover, carbon electrodes are used to store energy. Saltwater batteries have an extended lifecycle of up to 10-15 years. The reason is the use of carbon electrodes, which are way lighter than heavy metals, avoiding corrosion, and lower thermal stress than other batteries.

Flow Batteries

Redox Flow Batteries are required for commercial and industrial purposes. Flow batteries use a liquid electrolyte held in separate tanks. The electrolyte is pumped into the central reaction chamber and produces electricity through reversible chemical reactions. Redox flow battery provides highly stable and long-duration energy storage, having a lifespan of 15-20 years.

2. Depth of Discharge and Battery Usage

The depth of discharge means the total amount of battery capacity that is used when it is discharged. A higher depth of discharge means that your battery will have more stress on it, ultimately reducing its lifespan. 

For this reason, avoid using up the battery to its full capacity during discharge. Use the battery up to its recommended depth of discharge (DOD) value for maximum lifespan. This means if you have a 5-kilowatt battery with a DOD of 70% then use 3.5 kilowatts of it during every cycle for quality performance.

Most of the manufacturers suggest the minimum DOD value for your battery. Here’s a breakdown of how a DOD would affect your battery lifespan.

Temperature Exposure

Temperate exposure is a significant factor that might affect your solar battery life. Batteries work well at a standard temperature of 20 – 25°C, which is 68-77°F. In cold temperatures, solar batteries lose efficiency and capacity while they charge and are used up. Constant functioning at low temperatures can permanently lower its charging capacity, and your battery degrades much faster. 

High temperatures must also be avoided. Every 8°C(14°F) increase in surrounding temperature can reduce 50% of your battery’s life. That’s quite a lot! This is why you need effective management of your battery temperature for maximum longevity.

Which Battery Lasts the Longest?

Redox flow batteries are the clear winner for having the longest life span. While these batteries have better charging capabilities and last a higher cycle life, these batteries are large and are preferred for commercial use. 

Flow batteries can last up to 15 – 20 years, and degrade at a much slower rate than lead-acid or lithium-ion batteries. Moreover, the life cycles are also much higher, up to 10,000, making them last considerably longer.

Lithium-ion phosphate (LiFePO4) batteries are also effective for residential use. LFP batteries last longer as compared to traditional lead-acid batteries and have better temperature tolerance. As a result, they are expected to degrade much more slowly and deliver better performance for a much longer lifespan.

How To Maximize Your Solar Battery’s Lifespan?

You finally got your solar panel installed at your home, and now you’re looking for the best battery. You also figured out that a high-value solar battery is the one that delivers quality returns. Now, what can you further do to maximize battery output? 

Well, we got you covered with that, too. Letting you discover the key solar battery feature that can help you potentially increase your solar battery lifespan.

Maintain Your Battery Temperature

The solar battery temperature adversely affects its lifespan! It’s like a car engine that works best at the optimal temperature. This is exactly where controlling your battery temperature jumps in!

Keep your battery away from hot temperatures, and that includes direct sunlight. Even keep it away from small sheds or small enclosures that are easily heated. Garages or rooms with better airflow help you keep the temperature more stable and avoid heat being trapped.

Keep Optimal Charge Levels

Maintain the recommended charge levels for your solar batteries. If you regularly discharge your solar battery above the required depth of discharge level, you might end up damaging it. The performance is going to reduce, and that’s what you don’t want to happen. 

Adhere to the guidelines provided by the manufacturers. The ideal DoD for lead-acid batteries is 50% and for lithium-ion batteries is 80 to 90%. That’s exactly what you will need to keep in the long run for maximized lifespan and performance.

Clean and Maintain it Regularly

Clean your solar batteries regularly. Your batteries will thank you for the longer life. Look for corrosion by examining the battery terminals first. These are typically white or greenish deposits that might appear. Get an expert to get it maintained and cleaned to avoid degradation over time.

Also, you need to clean your battery of any dust and debris to avoid corrosion, short circuits, and let it maintain effective electrical contact. Performing these acts could serve as a lifesaver to maximize the return on your solar battery investment.

Use a Solar Battery Management System (BMS)

A Solar Battery Management System (BMS) is an effective way to monitor and track your solar battery performance. Make sure that it works in optimal conditions. This is how your battery delivers quality performance, safety, and prolonged lifespan.

A BMS system monitors the key solar battery aspects like temperature, DoD, SoC, overcharging, and every other aspect that might be necessary. An easy-to-use solar battery management system enables you to enhance your PV system’s ability to produce reliable and quality energy for years to come.

Conclusion

While choosing a solar battery, the lifespan shouldn’t be the only factor that you consider. There are other crucial aspects like the battery cost, power output, available space, and more. This allows you to make a better battery choice according to your home’s needs. For example, a flow battery lasts far longer and is much heat heat-tolerant than a lithium-ion battery. However, it takes a much larger space, making lithium-ion batteries a much better choice for your residential uses. 

Moreover, a lithium-ion battery may seem to last longer than lead-acid batteries, but they come with a much higher upfront cost. So, considering all these factors can help you make a better solar battery choice for your home. Solar Panel Installers is here to make things easy for you. Offering expert insights on solar battery installation and lifespan, we are where to make the entire process hassle-free for you. National Renewable Energy Laboratory

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