Key points
- Most home batteries now use lithium iron phosphate (LFP) cells and carry a 10-year warranty, usually guaranteeing 70% of capacity at the end.
- Many warranties also have a throughput cap in MWh, often equal to roughly 2,800–3,000 full cycles, which can end cover before 10 years if you cycle hard.
- In independent testing in Canberra, a Tesla Powerwall 2 kept about 79% of its capacity after the equivalent of 6.9 years of daily cycling.
- Heat, deep daily cycling and extra VPP use are the main things that shorten battery life.
- A battery doesn’t stop at the end of its warranty. It keeps working with less capacity until it’s no longer useful.
How long do solar batteries last? A modern lithium home battery should last at least 10 years, which is what most manufacturers warrant, and many will keep working beyond that with reduced capacity. Lifespan depends on how many charge cycles the battery does, how hot it gets and how it’s installed. Here’s what the warranties really promise, what independent testing found, and how to get the most life from your battery in South Australia and Victoria.
How long do solar batteries last in practice?
Batteries don’t fail on a set date. They gradually lose capacity, so a 13.5 kWh battery might hold 12 kWh after a few years and less again later. Most manufacturers guarantee around 70% of the original usable capacity after 10 years. At that point a 13.5 kWh battery would still store about 9.5 kWh, which is useful for many homes.
Because LFP home batteries have only been widely installed in Australia in recent years, there isn’t much long-term field data beyond 10 years. The sensible approach is to plan for about 10 years of full performance and treat anything beyond that as a bonus. This guide is part of our complete guide to home solar batteries.
Cycles, capacity fade and calendar ageing explained
- Cycle: one full charge and discharge. Two half discharges count as about one cycle. A home battery that fills from solar and empties overnight does up to one cycle a day, about 365 a year.
- Capacity fade: the gradual loss of storage as the battery ages and cycles.
- Calendar ageing: capacity lost with time, even with light use. Heat speeds it up.
- Depth of discharge: how much of the battery’s capacity is used each cycle. Manufacturers build buffers into the usable figure so you can use the full rated usable capacity.
Manufacturers often quote high cycle numbers for LFP cells. Sigenergy, for example, has claimed “up to 10,000 cycles” for its newer modules. But the warranty is what counts. SolarQuotes calculated that the 26.68 MWh warranty cap on Sigenergy’s BAT 10.0 module equates to about 3,046 full cycles.
What do solar battery warranties actually cover?
Battery warranties usually end at whichever comes first: a number of years, or a total amount of energy put through the battery (throughput, in MWh). Here’s how some popular batteries compare, based on Australian warranty documents and trade press as of October 2026:
| Battery | Years | Retained capacity | Throughput limit |
|---|---|---|---|
| Tesla Powerwall 2 and 3 | 10 | 70% | Unlimited for solar self-use, time-based control and backup; 37.8 MWh for other uses |
| Sigenergy SigenStor modules | 10 | 70% | 15.84 MWh (BAT 5.0) to 26.68 MWh (BAT 10.0) |
| Sungrow SBR | 10 | 70% | 26.88 MWh (SBR096) to 71.68 MWh (SBR256) |
| BYD Battery-Box Premium HVS/HVM | 10 | 70% | Minimum throughput, e.g. 34.15 MWh for HVM 11.0 |
| Enphase IQ Battery 5P | 15 | Per warranty | Up to 6,000 cycles |
To make sense of a throughput cap, divide it by the usable capacity. A Sungrow SBR096 (9.6 kWh) with a 26.88 MWh cap is covered for about 2,800 full cycles. If it did one full cycle every single day, it would reach the cap in about 7.7 years. In practice most home batteries do less than a full cycle on many days, especially in winter, so most will reach the 10-year limit first. Joining a VPP or charging from the grid twice a day changes that maths. For more on how brands compare, see our home battery brands comparison.
Tip: Ask your installer for the full warranty document, not just the brochure. Check the throughput cap, how retained capacity is measured, installation conditions, and whether gateways or controllers have shorter cover than the battery.
What does independent testing show?
The ARENA-funded Battery Test Centre in Canberra tested 26 home batteries between 2016 and 2022. Most were fully cycled three times a day, compressing about three years of normal use into one, in a room that ranged from 10°C to 36°C. SolarQuotes’ summary of the final results found:
| Battery tested | Capacity retained | Equivalent years of daily cycling |
|---|---|---|
| Sony Fortelion | ~81% | ~10 |
| Tesla Powerwall 2 | ~79% | 6.9 (projected ~70% at 10) |
| Pylontech US2000B | ~77% | 7.8 |
| LG Chem RESU HV | ~75% | 5.6 (projected ~55% at 10) |
| Tesla Powerwall 1 | ~59% | 7 |
Only 2 of the 26 batteries ran fault-free, though none of the failures were dangerous. Batteries without a communication link to the inverter performed poorly, and heat caused derating. These were older models tested one unit each, so treat the results as a guide, not a verdict on today’s products. The key lesson still stands: choose an established brand and installer who’ll be around to honour the warranty.
What shortens a solar battery’s life?
- Heat. ARENA’s Battery Test Centre reported the pack with the highest cell temperatures faded faster. A battery on a west-facing wall in direct afternoon sun in an Adelaide summer works harder than one in a shaded spot.
- Heavy cycling. A battery that’s too small for the home is emptied completely every night and uses up its cycles faster.
- Extra cycles from VPPs or grid trading. These add throughput, which can matter if your warranty has a cap.
- Poor installation. AS/NZS 5139 sets rules on where batteries can go. Ignoring the manufacturer’s location and ventilation requirements can void the warranty.
- Old firmware or poor communication between battery and inverter.
How to make your battery last longer
- Install it in a shaded, ventilated spot within the manufacturer’s temperature range, such as a south-facing wall or garage where permitted.
- Size it properly so it isn’t drained to the minimum every night. See what size solar battery you need.
- Check VPP terms against your warranty before joining. Our VPP guide for SA and Victoria covers what to ask.
- Keep firmware updated and monitoring online, so faults are picked up early. Our solar monitoring guide explains what to watch.
- Keep the area clear. Don’t stack boxes against the battery or block its vents.
What happens when a battery reaches the end of its life?
At the end of its warranty, a battery usually keeps working, just with less capacity. You can keep using it as long as it still covers enough of your evening use. When it no longer does, you can add capacity (if the system is modular and parts are still available) or replace it.
The inverter is the other part to watch. Batteries with a built-in inverter, and the hybrid inverters that run modular batteries, can have different warranty terms to the cells. Check both on your quote.
For disposal, the national B-cycle battery stewardship scheme was reauthorised by the ACCC until 2030, but household solar batteries generally aren’t accepted at B-cycle drop-off points. Ask your installer or the manufacturer about take-back and recycling when the time comes. Panels age on a different timeline; see how long solar panels last.
Does battery lifespan affect whether it’s worth buying?
Yes. If a battery’s payback is around 6–8 years, as it often is in Adelaide, there’s a comfortable margin inside a 10-year warranty. If your payback is 12–15 years, as is common in Melbourne, the battery may not pay for itself on bill savings before its warranty ends, so backup and price protection need to be part of the decision. Read is a solar battery worth it for the full picture.
Frequently asked questions
How many years does a home battery last in Australia?
Most lithium home batteries are warranted for 10 years and many should work beyond that with reduced capacity. Independent Canberra testing found a Tesla Powerwall 2 kept about 79% of its capacity after the equivalent of 6.9 years of daily cycling. Heat, heavy cycling and installation quality all affect how long yours lasts.
What does 70% retained capacity mean?
It means the manufacturer guarantees the battery will still hold at least 70% of its original usable capacity at the end of the warranty period, provided you’ve met the warranty conditions. For a 13.5 kWh battery that’s about 9.5 kWh. If it falls below that within the warranty, the manufacturer should repair or replace it.
Does joining a VPP shorten battery life?
It can add cycles, which adds wear and counts towards any throughput cap in your warranty. How much depends on how often the VPP uses your battery. Some warranties treat VPP use differently from normal self-use, so check the warranty terms and ask the VPP operator how many events it ran last year.
Can a solar battery be recycled?
Yes, lithium batteries can be recycled, but household solar batteries generally aren’t accepted at B-cycle drop-off points for small batteries. When your battery reaches the end of its life, ask your installer or the manufacturer about take-back and recycling options. Never put a home battery in household waste.
Want a battery that’s sized and installed to last? Our Adelaide and Melbourne installers follow AS/NZS 5139 and the manufacturer’s location rules on every job. See our solar battery installation page or get a free quote.
Sources: SolarQuotes – Canberra Battery Test Centre final report (15 Aug 2022); ARENA – Battery Test Centre Report 5; Tesla – Powerwall Limited Warranty (Australia and New Zealand) (2026); Sungrow – HV Battery Limited Warranty V8.0 (Oct 2024); SolarQuotes – New Sigenergy battery modules (23 Dec 2025); ACT Government – Batteries recycling. Warranty terms change; check the current document for your exact model. Featured image: Yo-Co-Man / Wikimedia Commons, CC BY-SA 4.0.
