There are so many benefits to adding battery storage to your solar power system, from increasing energy independence to saving more on utility bills. But solar battery storage can also be a significant investment, and it's important to weigh up your options carefully. One of the most common questions we get is around battery lifespan.
In this blog, we’ll explain how long solar batteries last, factors that affect solar battery lifespan, and signs that you may need to replace your solar battery.
Key takeaways:
The most common type of solar battery is lithium-ion, such as the Tesla Powerwall. Under average operating conditions users can expect an operational lifespan of around 10 to 15 years, depending on various factors (we’ll cover this later in the article). While this is a fair amount of time, it does mean you’ll likely need to replace your solar battery at least once within the 25 to 30 years lifespan of your solar panel system.
Thankfully, solar batteries don’t just suddenly stop working once they reach the end of their lifespan. Instead, their performance will slowly decline over time until it's no longer recommended or feasible to continue using them. As such, monitoring the batteries performance over time will give you some insight into its health and remaining time.
Battery lifespan can be measured in two ways:
Similar Reading: How To Choose a Home Battery Backup System?
Various factors can affect the lifespan of your solar batteries, including:
Let’s explore how each of these variables affects solar battery lifespan.
Just like your smartphone or laptop, the frequency of your solar battery usage can affect its lifespan. The more you charge and discharge your battery, the quicker it’ll lose its ability to hold a charge. Eventually, after a number of cycles, your battery might struggle to store and release enough energy to be truly useful.
This is why solar battery lifespans can vary so greatly – the more you use your solar battery, the shorter its lifespan. So if you rely on your battery only during a power outage, it will last longer than a battery that is discharged and recharged every day.
To help extend solar battery life, pay attention to the manufacturer’s recommended depth of discharge (DoD). This percentage tells you how much of a battery’s stored energy you can safely use without harming its health. For example, the standard DoD of a lithium-ion solar battery is around 90%. This means that with a capacity of 13 kWh, you can use up to 11.7 kWh while limiting battery degradation.
It’s important to not push your battery beyond its recommended DoD as that can significantly reduce its lifespan. Fortunately, most modern batteries have inbuilt protective systems that stop you from draining 100% of their capacity.
There are three main types of solar batteries: lead-acid, lithium-ion, and flow batteries. Each of these battery types has a different composition, storage capacity, and expected lifespan.
Lead acid batteries are the oldest type of solar battery, known for a high watt-hour capacity and low price point that makes them popular in off-grid solar systems. However, their lifespan is the shortest on the market at around five years.
These batteries also have a low depth of discharge (DoD) rate, usually ranging from 30% to 50%. This means you can only use a small portion of stored energy at a time, which can be quite limiting. While the lower price point of lead acid batteries might be attractive, their shorter lifespan and need for more frequent replacements can add up to make them more costly in the long run.
Lithium-ion batteries are the most common solar batteries on the market, with the best storage capacity and longest lifespan. They have a DoD rate of 80% to 95%, depending on the manufacturer, which means you can safely access more stored energy without compromising the battery’s lifespan.
Lithium-ion batteries are more expensive than lead acid batteries, although the long lifespan of around 10 to 15 years can make the added investment worth it by saving you money on replacements over time.
One thing to note is that lifespans can vary even within the broader category of lithium-ion solar batteries. According to the National Renewable Energy Laboratory (NREL), for example, lithium iron phosphate (LFP) batteries are less affected by certain degradation factors, such as high temperature and DoD, than lithium nickel manganese cobalt oxide (NMC) batteries. On the other hand, NMC batteries are less affected by a high average state of charge (keeping the battery fully charged for extended periods) than LFP batteries.
This highlights that there’s rarely a clear-cut answer when it comes to solar battery lifespan, and the type of battery you choose – as well as how you use it – can both significantly impact how long it lasts.
Keep Reading: How Many Batteries Do You Need To Run a House on Solar?
Flow batteries are a relatively new player in the solar energy market. They work by storing energy in liquid electrolyte solutions that flow through a cell stack to charge and discharge. This unique design eliminates the need for corrosive materials found in other battery types, with the most common types using vanadium ions or zinc bromide.
One standout feature of flow batteries is their 100% DoD, which means you can fully deplete the stored energy without damaging the battery. Depending on their specific type, flow batteries can have lifespans of more than 25 years. While they show promise as an alternative to lithium-ion, flow batteries are an early-stage technology and have yet to take over the market – mostly due to their higher costs compared to the other two options.
Below is a quick snapshot of the lifespan of different solar battery types.
| BATTERY TYPE |
CYCLE LIFE |
OPERATIONAL LIFESPAN |
| Lead acid |
500 to 1,000 |
~ 5 years |
| Lithium-ion (non-LFP) |
500 to 1,000 |
10+ years |
| Lithium-ion phosphate (LFP) |
1,000 to 10,000 |
10 to 15 years |
| Flow batteries |
10,000+ |
25+ |
The environment where your solar batteries are stored can also affect their lifespan, especially when it comes to temperature. Generally, solar batteries are best kept out of extremely hot or extremely cold temperatures. If you store your battery outside, exposed to the harsh elements, it’s likely to degrade faster than if you were to keep it indoors in a more controlled environment. That doesn't mean you have to store your solar battery indoors – even a sheltered outdoor area can make a difference.
When temperatures are too hot, the chemical reaction in batteries happens more quickly. This naturally increases wear and tear and shortens the battery’s lifespan. In colder temperatures, on the other hand, electrons slow down and chemicals don’t last as long as they usually would, making the battery drain much faster.
Again, the type of battery you choose plays a role here:
Most solar batteries are able to handle environmental conditions outside their working range. But if they’re exposed to higher or lower temperatures too often, it can put extra strain on your battery and affect its performance or lifespan.
See More: Maximizing Solar Efficiency in Extreme Heat: A 2024 Guide
The beauty of solar batteries is that minimal maintenance is involved. In fact, you don’t need to do anything to keep your solar batteries functioning well, unless you notice an issue with their performance or appearance. In that case, you should contact your solar battery installer and ask them to perform an inspection and any necessary repairs.
That said, there are a few things you can do to make sure your solar battery lasts as long as possible. This includes:
With proper maintenance, solar batteries can maintain optimal performance and last longer.
Similar Reading: How Long Do Solar Panels Last?
There are a few signs that can signal your solar battery is nearing the end of its lifespan. These can slightly differ depending on the type of solar battery you have and how you use it, however here are some things to look out for:
Deep cycle batteries have a depth of discharge (DoD) of at least 80%. This means you can use 80% of a battery’s stored energy without affecting its health. Most high-quality solar batteries on the market today are deep cycle batteries.
With a lifespan of around 25 to 30 years, solar panels last longer than solar batteries. The most popular lithium-ion solar batteries last around 15 years, meaning you’ll likely need to replace your solar battery once throughout the lifetime of your solar panels. That said, when it comes time to change your energy storage, solar batteries will likely be much more affordable than they are today.
Solar batteries can help you maximize the efficiency of your solar system and get more out of your investment. With a solar battery, more of your home’s overall electricity use will be fulfilled by your solar array, reducing your utility bill and reducing your carbon footprint. But with so many options out there, it can be difficult to know which choice to make. We’re here to help!
Our expert solar consultants can help you choose the best solar battery setup for your needs, whether you're looking for backup power during an outage or a whole-home storage solution. We’ll also show you how to optimize usage to maximize your battery’s lifespan. If you’re ready to explore solar battery options or have questions about upgrading your system, contact Sun Valley Solar Solutions today for free, no-obligation guidance.