Battery warranties compared
| Battery | Warranty | End-of-warranty capacity |
|---|---|---|
| Tesla Powerwall 3 | 10 years | 70% |
| Enphase IQ Battery 5P | 15 years or 6,000 cycles | 60% |
| Sungrow SBR | 10 years | See terms |
| BYD Battery-Box | 10 years | See terms |
| AlphaESS SMILE | 10 years if connected to Alpha monitoring | 70% of usable capacity |
Read the conditions. Some warranties end early once a set amount of energy has passed through the battery, and some require the battery to stay online so the maker can monitor it.
What wears a battery out
- Cycles. Each full charge and discharge uses a little of the battery's life. Daily solar cycling is what home batteries are designed for.
- Heat. High temperatures speed up ageing. Shade and ventilation matter, especially on west-facing walls.
- Extra cycling. VPP events and grid charging add throughput, which may count toward warranty limits.
Lifespan and payback
A battery has to pay for itself within its useful life. If payback is longer than the warranty, you are relying on it lasting beyond the warranty to come out ahead. Solar Choice's August 2026 index put the cost per warrantied kWh at $0.28 for 16 to 20 kWh batteries and $0.20 for 40 to 50 kWh. See is a battery worth it.
Register your battery
Some warranties require registration or an internet connection. Do it on installation day and keep the paperwork.
Common questions
Most come with a 10-year warranty, and Enphase offers 15 years. Many will keep working beyond that at reduced capacity.
The battery keeps working but holds less charge. Warranties usually guarantee 60 to 70% of the original capacity at the end of the term.
Yes, gradually. Heat and heavy cycling speed this up. LFP batteries, now the most common type, age slowly.
Sources
Warranty terms come from manufacturer documents for Australia. Cost per warrantied kWh is from the Solar Choice Battery Price Index. Last checked October 2026. Prices include GST unless we say otherwise.