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How Long Do Solar Batteries Last?

How Long Do Solar Batteries Last

As the world pivots towards sustainable energy solutions, solar power has become the front-runner in the race. As an Australian homeowner, you may have already installed solar panels and embraced this change. But have you ever wondered, how long do solar batteries last?

I’m going to be answering that shortly as well as other relevant topics. Below is a list of everything this article covers. Feel free to tap on any of the bullets to skip sections.

Got your reading glasses ready? Let’s start.

How long does a solar battery last?

On average, modern solar batteries last between 8 and 15 years, with some even reaching the 20-year mark.

However, just like any other technology, this isn’t set in stone.

Multiple factors can influence a battery’s lifespan, including the type of battery you have, operating and environmental temperatures, depth of discharge, cycle life, and maintenance.

This brings us to the next point of our discussion.

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Factors that affect the lifespan of your solar battery

Infographic showing Factors that affect the lifespan of your solar battery
Infographic showing Factors that affect the lifespan of your solar battery

Battery type

There are 4 types of solar batteries commonly used in Australia: lithium, lead acid, saltwater, and solar gel.

Naturally, they each have their pros and cons. They’re all discussed in more detail in our buyer’s guide for solar batteries but here’s the rundown:

  • Lithium, particularly lithium-ion batteries, are the most popularly used in Australian homes. They’re affordable and can store a high density of energy while still being compact.
  • Lead acid batteries are older technology relative to lithium-ion batteries. They’re cheaper but are also larger, less efficient, less durable, and have a worse depth of discharge (more on this later).
  • Saltwater batteries are the most environmentally-friendly option and typically have a longer lifespan than lithium-ion batteries. The catch is that they store less energy and have lower power ratings.
  • Solar gel batteries are leak-free, so they offer the most flexibility in terms of installation. They’re also highly reliable. However, they’re also pricier than lithium-ion batteries and take longer to charge.

Operating and environmental temperatures

Solar batteries, like many electronic devices, have an optimal temperature range for operation. When operating within this range, they can perform at their best and achieve their full lifespan.

However, if the environmental temperature consistently exceeds the recommended operating temperature of your solar battery, it can degrade faster, thus reducing its lifespan.

This makes it particularly important to choose a battery that can handle Australia’s sometimes extreme climate and ensure it is installed in a location where it can stay within its optimal temperature range.

Depth of discharge (DoD) and cycle life

DoD refers to how much of a battery’s capacity can be used without damaging the solar battery.

Most of today’s solar batteries are designed to have a DoD of 80-95%. Meaning, if you had a 100 kWh battery, a 95% DoD would tell you that you can use 95 kWh without shortening your battery’s lifespan. Also, batteries with higher DoDs will be referred to as deep-cycle batteries.

Cycle life, on the other hand, refers to the number of complete charge-discharge cycles a battery can handle before it begins to lose capacity.

If a battery is regularly discharged beyond its recommended DoD, or if it has to go through more cycles than it is rated for, this can cause the battery to degrade faster and shorten its lifespan.

Maintenance and monitoring

Regardless of the type, all solar batteries require some level of maintenance. Lucky for you, that maintenance is mainly just performance monitoring sprinkled with some visual checks for damage.

Even luckier is that most modern solar batteries offer easy monitoring via smartphone apps. These apps will show you metrics such as charge levels and efficiency – all in the palm of your hand.

This makes it less technically demanding than it was for older models. The apps can even notify you of potential issues before they become serious.

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Solar battery warranties

A warranty is the manufacturer’s guarantee that your solar battery storage system will last a certain period and perform at a certain level. Granted, these details will vary from manufacturer to manufacturer.

Usually, though, solar batteries have a warrantied life of around 10 years.

That being said, do make an effort to read the warranty details of your solar battery. And, when doing so, pay close attention to the guaranteed cycle life, coverage duration, DoD, and others.

This will give you an idea of what to expect in terms of the lifespan of a solar battery, and help you make an informed purchase.

Solar batteries vs. solar panels: Do they have the same lifespan?

No, they don’t have the same lifespan. Solar batteries typically have a shorter lifespan than solar panels.

While today’s solar panels last 25 years on average, solar batteries usually last half that duration. So expect to run through at least 2 solar batteries before you need to change the panels of your solar system.

This highlights the importance of 2 things:

  • Investing in high-quality batteries, and
  • Ensuring proper installation

When it comes to choosing a battery for your home’s solar power system, we can only guide you to a decision. But, ultimately, that choice is yours and yours alone.

About ensuring proper installation, however, we can do more. We have a network of pre-vetted solar installers that are ready to give you 3 FREE quotes. They’re all CEC-accredited, too, which is important if you want to qualify for rebates.

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When to replace your solar battery

When a solar battery needs to be replaced is both subjective and objective.

Subjective because, really, it’s mostly up to you. Objectively, though, there are visual and performance-based factors.

Visually, check for any leaks, bulges, or any other signs of damage. These are usually tell-tale signs that your batteries need to be replaced or, at the very least, checked by a professional.

Performance-wise, check for efficiency and how well they can hold their charge. Relative to visual damages, performance-based factors are more subtle, so be sure to establish a baseline when you get your batteries or refer to the manufacturer’s spec sheet.

Generally, though, solar batteries (or any battery for that matter) will be considered “dead” when they’ve lost 30% of their original capacity.

Recommended: What size solar battery do you need?

FAQs:

How long can a solar battery hold a charge?

On average, a fully charged solar battery can hold its charge for one to five days. Although, this is going to be different depending on a few factors, including its capacity and type.

How long will a solar battery last during a power outage?

How long a solar battery will last during a power outage depends on its capacity. The larger your battery, the longer it can power your home. For reference, a 10 kW solar battery can power the average home for a full 24 hours.

Conclusion

To recap, a modern solar battery will last you a good 8-15 years, if not more. Of the many types, lithium-ion solar batteries are the most commonly used in Australian homes but other types such as lead acid, saltwater, and solar gel are also available.

The type of solar battery you choose will also influence how long it’s going to last. Other factors also include environmental conditions, depth of discharge, cycle life, and how well you maintain your battery.

Now, replacing your solar battery is partly a subjective decision. Most solar batteries will still be functional even when they’ve reached the end of their warrantied life after all.

Objectively, though, physical damages such as bulges and leaks, as well as performance-based shortcomings should tell you when your solar battery needs to be replaced.