How long do solar batteries last?
Last updated 2 October 2026
Cycles
A cycle is roughly one full charge and discharge of the battery. Lithium batteries don't fail after a fixed number of cycles, they gradually lose some of their original capacity each cycle, which is why lifespan is usually expressed as a cycle count paired with a minimum capacity still guaranteed at the end of it.
Depth of discharge
Depth of discharge (DoD) is how much of the battery's capacity is actually usable on a normal cycle, as a percentage of its total capacity. A battery rarely discharges to 0% in everyday use, a small reserve is usually kept back, and allowing deeper, more frequent discharges tends to wear a battery faster than shallower ones.
Degradation
Degradation is the gradual, expected loss of usable capacity over time and use, not a fault. It's why warranties guarantee a minimum retained capacity (for example, 70%) at a given age or cycle count rather than promising the battery never loses capacity at all.
What published warranties actually guarantee
Not every manufacturer publishes a cycle count, some guarantee a throughput cap or a number of years instead. From the models we track, these publish an explicit cycle figure:
- Enphase IQ Battery 5P: 15 years, up to 6,000 cycles : the longest standard residential warranty in the AU market, per Enphase.
See how warranty terms work for the full picture, including models that guarantee a throughput cap or years instead of a cycle count, or compare every published model.
Compare battery brands
See every battery brand and model →Common questions
Does a battery stop working once its warranty ends?+
No. A warranty is a guarantee of minimum performance up to a point, not an expiry date. Most batteries keep working after their warranty period ends, just with less guaranteed capacity than when new.
Does using a battery every day wear it out faster?+
Regular daily cycling is what these batteries are designed for, and is accounted for in their published cycle and throughput figures. It's deep, frequent discharges beyond normal use that tend to accelerate wear.