Most home solar batteries last 10 to 15 years, and they come with a 10-year warranty as standard. Because they keep saving you money the whole time, a battery that outlives its warranty is money in the bank well beyond payback.
Lifespan, warranty and capacity
Battery life is measured in charge cycles, one cycle being a full charge and discharge. Modern lithium iron phosphate (LFP) batteries are rated for thousands of cycles, which for a home doing roughly one cycle a day adds up to well over ten years. The 10-year warranty usually guarantees the battery still holds a set share of its original capacity, often around 60 to 70%, at year ten. It does not just stop working at that point, it simply holds a little less.
What affects how long a battery lasts
- Chemistry. LFP batteries, used by most modern brands, are valued for long cycle life and stability.
- How hard it works. Deep daily cycling is normal and expected, the warranty accounts for it.
- Temperature. Extreme heat is the main enemy, which is why installers mount batteries out of direct afternoon sun.
- Quality of install. An accredited installer sets it up to run within safe limits, which protects its life.
What about replacement?
By the time a battery needs replacing, the technology will be cheaper and better, and your system will have paid for itself many times over. For the full payback picture, see are solar batteries worth it? and put your own numbers in the savings calculator.