How Long Do Home Solar Batteries Last? What To Know
Most people know that solar panels last for decades, and are typically warrantied for 25 years. And many know that solar batteries store (but don’t produce) energy for you to draw from when you choose. But how long do home solar batteries last?
Citadel Roofing & Solar wants you to know what to expect when you invest in Solar+Storage, whether you’re seeking even greater electricity savings or backup power during outages. So here’s an overview of the expected life of residential solar batteries, factors that impact that lifespan, and how to decide if batteries provide the value you’re looking for.
How long does a solar battery last?
Most manufacturers warranty solar batteries for 10 years, so you can reasonably expect them to last that long or a bit longer. But lifespan is impacted by the technology used, how frequently the battery is drawn upon, and the surrounding climate.
Those who like to hedge their bets estimate battery life at a broader range of 5 to 15 years since usage greatly affects how long a battery lasts. It's important to note that, unlike many products, battery life is measured in cycles as well as years, which we explain below.
Regardless of your battery’s exact lifespan, it’s realistic to expect you will need to replace your battery system before your solar panels.
At the end of its useful life, the system won’t necessarily die completely. But it will not provide a strong enough charge to do its job. It’s just like your tablet’s or smartphone’s battery when they’re aging and take longer to charge or never seem to charge fully.
Let’s explore the factors impacting battery life.
Which battery type you choose
Different batteries have different life expectancies, so it almost goes without saying that the brand you choose impacts how long your battery will last. We address the leading brands later in this article.
Most of the residential batteries installed in the U.S. today are lithium-ion. One reason lithium-ion is the technology of choice is its long life.
How much you use your battery
As we said, battery life is measured in cycles as well as years. Each draining and recharging of the battery constitutes a cycle. After a certain number of cycles, battery performance may diminish.
Many solar battery systems are scheduled to cycle daily. How quickly you go through a cycle depends on your energy needs, the size of your battery system, and the system settings. Your system should be sized appropriately for your needs to ensure maximum performance.
Like all batteries (think your phone, or even a flashlight), the older they get and the more cycles they’ve gone through, the less they can hold a charge and power your device until they stop functioning at a useful level.
This is why some battery warranties list a maximum number of cycles allowed.
The surrounding climate and temperature
Like most batteries, the lithium-ion batteries in solar energy storage systems don’t like extremely hot or cold temperatures. Highs and lows can impact performance and life.
This is generally not an issue for California homeowners in warmer climates.
Their homes and garages, and even yards in some cases, remain well within the 0°F to 140°F range considered optimal for lithium-ion batteries.
Still, the more controlled the environment and the milder the temperature swings, the better it is for your battery. That’s why Citadel generally does not install batteries on a home’s south side, which has direct sun exposure.
California’s colder climates call for indoor installation of the batteries, to assure optimal performance.
(On a related point, some cities, and towns now have rules about where batteries can be installed on your property.)
Solar battery warranties and life spans by brand
The manufacturers’ warranties give you a sense of what those companies believe is their battery’s lifespan. Companies typically warrant for slightly less than how long they think the system will last, so they’re not caught holding the bag for old systems that have outlived their best years.
Solar battery warranties are more complex than the solar panel and inverter warranties because they are affected so much more by how they are used. So most warranties cover a set number of years or a set number of cycles—whichever comes first. This is similar to some car warranties, which are measured in years or miles, whichever comes first.
Following are the battery warranties for the leading brands, in terms of years and cycles—the two most common measurements. Many warranties have temperature stipulations and other qualifiers. Some include a cap for total energy run through the battery (“throughput”) instead of, or in addition to, years and cycles.
So be sure to discuss the warranty with your solar company, and to read the fine print.
Tesla Powerwall Warranty
Tesla guarantees its Powerwall 2 will maintain at least 70 percent of its capacity for 10 years, with no limit on the number of cycles.
Enphase IQ Battery Warranty
Enphase guarantees its IQ battery will retain at least 70 percent of its storage capacity for 10 years, or once it’s completed 4,000 cycles, whichever comes first. They offer an optional 5-year warranty extension.
LG Chem Battery Warranty
LG guarantees its LG Chem battery will retain at least 60% of its capacity for 10 years.
SolarEdge Battery Warranty
SolarEdge batteries are warrantied to perform at 70 percent for 10 years, with no limit on the number of cycles.
Sonnen Battery Warranty
Sonnen guarantees its SonnenCore battery for 10 years or 10,000 cycles, whichever comes first.
How do I tell if my solar battery is underperforming?
If your battery seems to be draining quickly or not holding a charge as well, it might be time to ask a technician to have a look. Most systems include some alerts for system failure or malfunction.
Your installation company will walk you through what to expect from your battery and how to monitor its performance.
Are solar batteries worth it?
Whether or not Solar+Storage will deliver enough value for you depends on a number of considerations that you can discuss with your family and your solar consultant.
A solar energy system alone is a big investment, although it pays you back in time, unlike almost anything else in this world. Adding energy storage or batteries to your solar system can double that investment. So is it worth getting a battery with your solar panels or not?
Things that impact how much value you would get from a solar battery include:
- Roof Size: Very small roofs may not accommodate enough solar panels to charge a battery after household usage is met.
- Emergency Backup: Having power during a utility outage, planned or unplanned, is more important for some people than others. If constant electricity is critical to you, solar batteries can literally be a life-saver.
- Time-of-Use Rates: The big utilities in California all charge rates that increase during peak usage times, such as late afternoon and evening. For their customers, storage allows you to use your own, less expensive, stored solar power rather than pay the utility’s pricey peak rate.
- Incentives: Government programs can reduce your battery investment price tag. All Americans who purchase solar energy storage are potentially eligible for the federal Investment Tax Credit that pays you back 26 percent (in 2022) of the system price, as long as the system is charged with solar. In addition, some Californians may qualify for the Self Generation Incentive Program (SGIP) which offers rebates for residential energy storage.
- Philosophy: For some, whether or not batteries are worth it is based on one simple thing: more independence from the utility. They want to capture and use as much of their solar as possible, rather than send any extra electricity into the utility grid. And they want some protection from utility rate increases.
Work with the experts at Citadel Roofing & Solar
Battery technology is relatively straightforward, but the calculations for how many batteries you need, how to design and configure your system, and even how your warranty impacts your choice, can be complex. An experienced and qualified installer can make it simple for you though.
Contact Citadel to learn more about Solar+Storage for your home. You can also learn more on these pages if you like:
- Everything You Need to Know About the Tesla Powerwall
- Storage for Homeowners
- Learn About Storage
- Solar + Storage 101
- How to Pay for Home Solar or Energy Storage
- Wildfire Season is Coming: Protect Yourself from Utility Outages