How Long Do Solar Batteries Last?
A solar battery can last anywhere from 5 to 25 years. A lithium-ion battery, which is the standard battery in most solar panel systems, has a lifespan of around 15 years.
Multiple factors influence solar battery lifespan, including installation, manufacturer, environment, maintenance, depth of discharge, cycle life, and battery type.
Keep reading to find out everything you need to know about how long solar batteries last.
The Average Solar Battery Lasts Around 15 Years
Most solar panel systems use a lithium-ion battery. On average, you can expect that lithium-ion battery to last around 15 years.
Typically, solar panel owners need to replace a battery once or twice throughout the lifespan of their panels. If the average solar panel array lasts 20 to 30 years, then you may need a single battery replacement at some point in the lifecycle of your panels.
However, depending on various factors, solar panel batteries could last as few as five years – or as many as 25 years or more.
Factors Impacting Solar Battery Lifespan
Sometimes, it’s worth investing in a better battery for a longer lifespan. In other cases, your battery lifespan is reduced through factors outside your control – like your environment and climate.
Here are some of the factors impacting solar battery lifespan:
Type of Battery
There are two main types of solar panel batteries: lead-acid batteries and lithium-ion batteries. Early solar panel systems tended to use lead-acid batteries, but most modern systems use lithium-ion batteries:
Lead-Acid: Lead acid batteries have a lifespan of 1,500 to 3,000 cycles, which means you need to replace them every three to five years. Originally popular in older solar panel systems, lead-acid batteries are less popular today because of their low lifespan.
Lithium-Ion: Most solar panel systems sold today use lithium-ion batteries. There are different lithium-ion battery manufacturers with different levels of quality. However, you can expect the average lithium-ion battery to last around 15 years.
Other Battery Types: There are other battery types available today, including saltwater batteries and flow batteries. Both battery types are relatively new, and their quality varies across manufacturers. It remains to be seen how long these alternative batteries could last.
Solar Battery Usage
Your solar battery lifespan depends on your usage cycles. Most solar batteries are deep-cycle batteries, which means they discharge around 80% of stored energy before recharging. This allows you to maximize each usage cycle and extend the lifespan of your battery.
Some solar batteries, especially older batteries, require manual discharging before recharging. Unless you discharge and recharge at maximum efficiency, this can reduce battery lifespan.
Solar Battery Temperature & Operating Environment
Solar batteries need to be kept at a specific temperature to optimize lifespan. Generally, those who live in areas with harsh temperatures should install solar batteries in a garage or basement. Those who live in areas with temperate or mild temperatures should install batteries outdoors.
Check your solar battery’s recommended temperature range to determine optimal placement in or around your house.
Depth of Discharge
Depth of discharge, or DoD, plays an important role in how long your solar batteries last. Each solar battery manufacturer has a specific recommended DoD.
DoD is the percentage of the battery’s stored energy you use. If you have a 10 kWh solar battery and you use 8 kWh of its charge, for example, you would have an 80% depth of discharge.
If you repeatedly ignore your manufacturer’s recommended DoD, you can expect a shorter battery lifespan. Check your solar battery’s recommended DoD to ensure optimal lifespan.
Solar Battery Maintenance
Proper maintenance extends the lifespan of your solar batteries. On average, you can expect to spend $100 to $400 per year to maintain your solar panel system and battery.
Active maintenance can avoid the need for major repairs. The better you maintain your battery, the longer it should last – and the sooner you can spot issues with your battery and panels.
Solar Battery Warranty
One of the best indicators of solar battery lifespan is the warranty. Solar batteries with a longer warranty tend to last longer than those with a shorter warranty. Manufacturers base the warranty on the expected lifespan of the battery.
The average lithium ion solar battery available today has a warranty of around ten years. Cheaper batteries have a shorter warranty, while higher-end batteries may have a longer warranty.
Many manufacturers also use cycle warranties, protecting the battery against a certain number of cycles. The average solar battery sold today, for example, may have a 5,000 to 10,000-cycle warranty.
Solar batteries last around 15 years, on average. That means you may need to replace your solar battery once or twice before replacing your solar panels.
Compare solar batteries and shop around to ensure you pick the solar battery with the optimal lifespan and ideal operating conditions for your unique needs.