How often do solar batteries need to be replaced?
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Short answer: about every 10–15 years. That's the federal government's average lifespan for a lithium-ion home battery; lead-acid lasts 5–10 [SB-S300, C]. Warranties promise less: most brands we cover guarantee at least 70% of capacity at 10 years, and the warranty can end sooner if the battery moves a set amount of energy [SB-S050, SB-S053, SB-S055, SB-S057, SB-S059, SB-S210, C].
On this page: How long they last / What the warranty promises / When the warranty ends early / Signs it's time / Replacing it
How long do solar batteries last in Australia?
| Part | Average lifespan |
|---|---|
| Lithium-ion battery | 10–15 years |
| Lead-acid battery | 5–10 years |
| String inverter | 10–15 years |
| Microinverter | 20–25 years |
| Solar panels | 20–30 years |
Source: energy.gov.au [SB-S300, C].
So your battery will likely need replacing before your panels. Your inverter may need replacing at about the same time [SB-S300, E].
What the warranty promises at 10 years
| Brand | Warranty floor at 10 years | Throughput cap |
|---|---|---|
| Tesla Powerwall 3 | 70% of 13.5 kWh | unlimited for self-use, time-based and backup; otherwise 37.8 MWh [SB-S053, C] |
| Sungrow SBR/SBH | 70% | unlimited for self-use and backup; otherwise by size, e.g. SBR256 71.68 MWh [SB-S050, C] |
| Sigenergy | 70% | 33.29 MWh per module [SB-S059, C] |
| FoxESS EQ4800 | 70% | 39.32 MWh (2 modules) to 176.94 MWh (9) [SB-S055, C] |
| BYD HVS/HVM | 70% | e.g. HVS 12.8: 38.53 MWh; HVM 22.1: 68.31 MWh [SB-S057, C] |
| Alpha ESS SMILE-G3 | 70% | 3.12 MWh per usable kWh [SB-S210, C] |
What 70% means: a 13.5 kWh battery could hold about 9.5 kWh at year 10 and still be inside warranty [SB-S053, E]. That's the floor, not a forecast; many batteries will hold more, but we haven't found Australian data on real-world fade.
When the warranty ends early
A throughput cap ends the warranty once the battery has moved that much energy, even before 10 years. As a guide, Sigenergy's cap works out to about 3,800 full charge-and-empty cycles per module, and Alpha ESS's to about 3,100 [SB-S059, SB-S060, SB-S210, E]. One full cycle a day is 3,650 in 10 years [SB-S300, SB-S053, E], so a battery that's emptied every night, or used in a VPP, can reach its cap around year 8 to 10 [SB-S300, SB-S053, E]. Tesla and Sungrow don't apply the cap to normal self-use [SB-S053, SB-S050, C].
Signs it's time
- It no longer covers your evening use, even after a sunny day [SB-S300, SB-S053, E].
- Your app shows usable capacity falling toward the warranty floor [SB-S300, SB-S053, E].
- The inverter fails and the replacement doesn't support your battery [SB-S300, SB-S053, E].
This page is about years. For how many hours a battery runs your house on one charge, see our runtime guide.
Replacing it
Replacing a battery needs a professional [SB-S300, C]. A new battery must be on the CEC approved list on the install date to get the federal discount [SB-S003, C]. A battery that replaces one already claimed at the same address may not qualify, because the program allows one battery per premises: ask before you budget for the discount [SB-S003, E]. For help picking the size for a replacement, see our sizes guide.
Ask your installer
- The warranty's 70% floor and throughput cap, in writing.
- How many cycles a year your use pattern (and any VPP) adds.
- Whether the inverter is likely to outlast the battery [SB-S300].
Next step: get quotes
Ask at least two accredited installers for a written quote that shows the model, usable kWh and the certificate count.
Rules checked 3 November 2026. Next scheduled check: before 1 January 2027 (STC step-down), and monthly for WA and NSW.