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Expected Lifespan of a Solar Battery

solar batteries

Solar battery storage can optimize your solar power system to use almost all of the power generated, increase your savings, and create a reliable system that works even when the sun isn’t shining. But how long do solar batteries really last? What can you do to increase the lifespan of your battery? And how can you tell if your battery isn’t working properly?

To best understand your system and everything it can do for you, knowing about the lifespan of your battery and what you can do to extend that lifespan is essential.

How long do solar batteries last?

Home solar battery units last anywhere between 5 and 15 years. If you were to install a solar battery right now, it’s almost certain you’ll need a replacement in the future to match the 20- to 30-year lifespan of your solar power system.

This might be a pretty large range, but you have more control over it than you might think.

Factors that influence solar battery lifespan

Several key elements play into solar battery lifespan, including what type of battery you choose, how often you use the battery, where it’s stored, and how well the battery is maintained.

To get the most value out of your solar battery, there are 3 major factors you must keep in mind.

Battery Usage

The best way to measure the lifespan of solar batteries isn’t in years, but rather in cycles.

A cycle is the amount of time it takes to drain and recharge a battery. Cycles are the best unit of measurement because you might only be using your solar battery once in a while, or you could use it all the time. A measurement in years won’t make much sense in either case.

You’ve likely experienced the way usage degrades batteries with your phone or laptop. When you first purchased your phone the battery may have lasted 12 hours, but after a few years it only lasted three.

This degradation is unfortunate, yet inevitable, when it comes to batteries. The more often you charge and discharge your battery, the less time the charge lasts. After a certain amount of cycles, your batteries won’t even be able to store and discharge enough energy to make it worth using them. That’s why the variation in the number of years a solar battery lasts is so large.

One way to help your batteries last longer is to be aware of the manufacturer’s recommended depth of discharge, or DoD. DoD is the percentage of the battery’s stored energy you use. For example, your battery’s capacity is 13.5 kWh, and you use 10 kWh of its charge. The depth of discharge would be 74%. Forcing your battery beyond its recommended DoD can greatly shorten the lifespan of your battery.

A second way to enhance your battery lifespan is by utilizing partial-discharge cycles. Use only 20% or 30% of your battery’s charge at a time, and for the best results, avoid charging your battery to 100%.

Battery Type

There are three types of solar batteries commonly used in solar storage: lithium-ion, lead-acid, and saltwater.

Lithium-Ion Batteries

Lithium-ion batteries are the most frequently used battery for solar storage system application. They offer a compact, lightweight solution with higher storage capacity and better efficiency. They also have a greater depth of discharge and longer solar battery lifespan.

Lithium-ion batteries are likely going to cost more than other battery choices and are best for home solar systems that are actively used. However, with the anticipated cycle length being several times higher than that of other solar battery choices, the extra money may be worth the initial investment. It could save you money in replacement costs down the road.

Lead-Acid Batteries

The second most popular option is the lead-acid battery. These are the least expensive kind of solar battery and they have a high watt-hour capacity which makes them a common choice for off-grid solar systems.

Compared to other options, however, they last for far fewer cycles, meaning their lifespan will be the shortest. They also have a lower depth of discharge (DoD) rate which means you can only use a portion of the energy that’s stored in the battery.

The best place to use a lead-acid battery is an off-grid solar installation that isn’t frequently used. This will avoid many of the downfalls linked with lead-acid batteries. Because of the lower usage rate of lead-acid batteries, you can save a considerable amount of money when designing a power backup system for something like a boat or an RV.

Saltwater Batteries

The third option, saltwater batteries, are fairly new to the market. Instead of using corrosive materials, they use salt to store and discharge energy, making them extremely safe and easy to recycle.

The anticipated cycle length of saltwater batteries falls in the middle of the three choices. They will likely last longer than lead-acid batteries, but not quite as long as lithium-ion batteries. They also have comparably high DoD rates to lithium-ion batteries.

Battery Environment

Like nearly everything using electricity, temperature matters. Extreme cold or heat will not do your battery any favors.

When exposed to high levels of heat, the chemical reactions inside the battery will accelerate. This will decrease its lifespan and increase the rate of wear and tear.

In extreme cold, the electrons slow down, and chemical reactions end sooner, draining the battery much faster than usual and leading to more frequent drain-recharge cycles.

The ideal temperature range is different for each battery type.

  • Lead-acid batteries are more sensitive to temperatures and many manufacturers recommend keeping lead-acid batteries around 40°F to 80°F.
  • For lithium-ion batteries, the recommended range is between 0°F and 140°F for best results. Do your best to avoid either end of the temperature spectrum.
  • Saltwater batteries will perform best at temperatures above roughly 23°F and below 104°F, more flexible than lead-acid batteries but not quite as much as lithium-ion batteries.

The best way to control the temperature of your battery is to store the batteries in a somewhat temperature-controlled area. Your storage system can last longer than if you had the batteries exposed to the harsh elements. Places like a garage or basement, or a part of the building that’s out of immediate threat from the elements are the best choice.

Signs your battery is bad

Eventually, over time, your battery will go out. Things to look for as your battery deteriorates are broken terminals, leaking, discoloration, cracks, ruptures, bulges, and bumps.

Broken terminals normally mean a short-circuit has occurred. If your battery has broken terminals, it is in dangerous condition and should be replaced as soon as possible. Bulging or bumps in the casing indicate overcharging which most often means there is a problem with the charge controller. If you find any cracks or ruptures, it means the battery has degraded considerably.


The lifespan of a battery used in home energy storage is largely dependent on you as the homeowner. From how often you use the battery you choose to the amount you charge it, you are making an impact on how long it will last.

Being able to identify what you can do to improve the lifespan of your battery is the first step towards maximum use, optimized efficiency, and enhanced savings. If you want to know more, are ready to have your own solar energy system, or would like an expert to take a look at your setup, let’s chat!

You can place yourself directly in our calendar or fill out the form on our website to schedule service, or call SolarUnion directly at (888) 815-6633.