How Long Does a Solar Battery Last? Your Questions Answered

Solar Battery

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If you have a solar panel system installed in your house, chances are you’ll also have a solar battery. These backup devices are an excellent way to store additional energy produced by your panels, but how long do solar batteries last? 

Solar batteries last between 5 and 15 years, depending on the unit’s model and how well it is maintained and kept. Solar batteries store extra electricity generated from your solar panels that you can use when your panels aren’t generating electricity, such as at night or on cloudy days. 

However, like all electronic devices, even the best solar batteries in Australia do not last forever. After some time, your batteries will lose their capacity, ability to hold their charge and overall efficiency. How long a solar battery lasts depends on many factors such as its type, charge cycles, usage, and more. This article helps you give an insight into the lifespan of solar batteries.

How Long Does a Solar Battery Last? 

Properly maintained solar batteries can last between 5 to 10 years, with some units lasting for over 15 years. Since solar power systems have a 20 to 30-year lifespan, you will need a replacement battery halfway through that lifespan.

A solar battery’s lifespan is mainly determined by its charge cycles. A charge cycle refers to a complete charge and discharge of a recyclable battery. 

The number of charge cycles depends on the type of battery. For example, a flooded battery can last for 300 to 700 cycles. Lithium batteries can often last up to 2000 cycles. A gel battery is efficient for up to 5000 cycles.

Useful Life vs Warrantied Life 

When purchasing and installing solar batteries, you might come across the terms “useful life” and “warrantied life.” Misunderstanding these terms could result in unexpected surprises and, sometimes, disappointment as you use your battery. 

Useful life – The useful life of the battery refers to the number of times your battery can be used before it is deemed unusable or inefficient. Generally, a solar battery is considered to have reached the end of its useful life when it does not meet 60% of its storage capacity. Yes, the battery can still function at lower percentages. However, it won’t give you a sufficient charge to meet your standard requirements.

Warrantied life – The warrantied life of a solar battery refers to the length of time that your battery is assured to perform efficiently under normal conditions. Warranties can be between 10 to 20 years, depending on the brand, model, and manufacturer. 

A warranty date expires when the published warranty date has passed, the battery surpasses its maximum cycle allocation, or the battery capacity is reached.

Note that warranty dates are just for guidance. There’s a possibility that your battery can last longer than the warranty date.

Do Solar Batteries Last Longer Than Solar Panels?

Typically, the lifespan of a solar battery is shorter than the solar panels it is connected to. A good-quality solar battery can last 5 to 15 years, while solar panels can last from 20 to 30 years. 

Again, how long a solar battery lasts depends on your system’s usage, operation, and maintenance. A high-quality solar battery that is well maintained can potentially outlast a poor-quality solar panel. 

Which Type of Solar Battery Lasts the Longest?

In general, lithium-ion solar batteries last the longest since they can supply more charging cycles than lead-acid batteries. This makes them ideal for providing main and auxiliary power to the grid. In addition, lithium-ion batteries have high charge and discharge efficiencies, making them suited for solar systems.

What Affects the Lifespan of a Solar Battery? 

The main factors affecting a solar battery’s lifespan include: 

Depth of Discharge – Depth of discharge refers to the degree to which a solar battery is used relative to the unit’s overall capacity. As the battery is charged and discharged over time, it degrades, gradually lessening its capacity to store energy. 

Temperature – When stored in high temperatures, the chemical activity inside a solar battery increases, which decreases the unit’s life. In temperatures lower than that recommended by the manufacturer, the solar battery’s capacity also decreases. Always be aware of the optimal temperature to maximise your battery life.

Type of Battery – The kind of battery you’re using is a factor in determining the lifespan of a solar battery.

  • Lead-Acid Batteries: Used for many years in off-grid systems, lead-acid batteries are the most affordable solar batteries on the market. This makes them popular choices. However, they have a shorter lifespan and lower depth of discharge when compared to lithium-ion batteries. 

  • Saltwater Batteries: These batteries rely on saltwater electrolytes to generate power rather than heavy metals. While they’re eco-friendly and recyclable, they have the same lifespan as lead-acid batteries. They’re also considered a new type of technology within the industry, so they don’t yet have the same recognition as other types of solar batteries. 

  • Lithium-Ion Batteries: Many people prefer lightweight and compact lithium-ion solar batteries. They have a longer lifespan and higher depth of discharge than lead-acid batteries. In addition, the cost of purchasing and installing lithium-ion batteries has decreased due to high demand.

Usage – As mentioned earlier, the lifespan of a solar battery depends on its usage cycles. Most solar batteries are deep-cycle batteries. This means they can use and discharge up to 80% of their stored energy before recharging is required. This is how solar batteries work to improve the efficiency of your solar system. 

Maintenance – Make sure that your battery is properly maintained. Each brand has its own maintenance procedures; always follow them. Clean the terminals regularly, and operate your battery within the manufacturer’s specifications. Have your battery checked and repaired immediately if there are problems.

Solar system maintenance can cost around $150 to $300 a year. Repair costs can range between $100 and $3000. 

How Can You Extend Your Solar Battery’s Lifespan?

The best ways to extend the life of your solar battery are:

Limit the number of batteries you have – The more batteries you have, the more connections you need. Every connection generates more electrical resistance, which can cause uneven charging, negatively affecting the life of your existing batteries.

Periodically rotate your batteries – If you have a large bank, rotating your batteries will help to balance the charge. The units in the middle of your battery bank may not receive an optimal charge compared to the batteries outside. So changing your battery positions from time to time will help to even out the charge.

Install efficient cabling – Using large battery connection cables will reduce resistance and enable even charging. For a 12V and 24V system, we recommend a 4/0 cable. For a 48V system, we suggest using a 2/0 cable.

Keep your batteries charged – Don’t leave your batteries uncharged for long periods as this can cause damage to the units and affect their maximum capacity. Set your charging source to allow continuous charging to your batteries. It’s also advisable not to completely drain your battery bank.

Maintain your solar batteries – Charge your batteries properly according to the manufacturer’s instructions. Clean the terminals regularly. You can even contact your local solar specialist to have them professionally maintained to prolong their life even more. 

Get your solar batteries equalised – Over time, your battery cells will become unevenly charged; this is normal in the cycling process. You can equalise the charges by periodically equalising your batteries. Equalising is intentional but controlled overcharging of your batteries. Ask your manufacturer or installer about the specifics of equalising your system.

Have your batteries installed in a safe location – Protect your batteries by putting them in an area at room temperature, which is around 25 degrees Celsius. Don’t expose them to extreme heat or cold. Protect them from moisture as well. Inside garages, laundries, and well-insulated sheds are the best way to keep them safe from the weather they’d face outside. 

When Should You Replace Your Solar Battery? 

You should replace your solar batteries when they are becoming inefficient and not holding a charge as well as they used to, which is after 10-15 years for most solar batteries. If you notice that your battery drains a charge considerably faster than it used to, then it’s probably time to change your battery.

Can You Replace a Solar Battery Without Replacing Your Entire Solar System? 

Yes, you can replace an expired or faulty solar battery without replacing your entire solar system since it’s just a matter of disconnecting your old batteries and reconnecting the new ones. A licensed electrician can have it done fairly quickly and easily. 

However, battery replacement needs to be done by a professional. Improper replacement not only damages the battery and will affect the unit’s efficiency. In addition, it’s illegal in most places in Australia to do it yourself, as it counts as electrical work that must meet Australian Solar System Standards

Related Questions: 

How Long Does a Tesla Solar Battery Last?

According to Tesla, a Tesla Powerwall solar battery can last up to 20 years. The company guarantees an efficient, useful life of 10 years or around 5,000 charge cycles. It also boasts of a 100% depth of discharge.

Can I Get Solar Batteries for My Business?

Yes, there are solar batteries available for both residential and commercial use. The range BYD battery boxes are a great example of high-end solar batteries with models for homes and businesses. 


This article is published in good faith and for general informational purposes only. JFK Electrical does not make any warranties about the ongoing completeness and reliability of this information. Always seek personalised advice on solar energy to ensure any recommendations suit your property and scenario.

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