What Happens When Your Solar Battery Dies? End of Life Guide

The answer depends heavily on the battery chemistry. The vast majority of home batteries sold in Australia today use lithium-ion technology, either lithium iron phosphate (LFP) or nickel manganese cobalt (NMC). These typically last 10 to 15 years under normal residential use. That means daily cycling: charging from solar during the day and discharging to power your home in the evening.

Older lead-acid batteries, which were common in off-grid setups before lithium prices came down, have a much shorter lifespan of around 5 to 7 years. If you had an early battery install using lead-acid technology, you may already be past the replacement point.

The warranty gives you a useful baseline. Most manufacturers offer a 10-year warranty guaranteeing that the battery will retain 70 to 80% of its original capacity. That doesn't mean the battery dies at year 10. It means the manufacturer is confident it will still hold at least 70 to 80% of its rated storage by then. Many batteries continue to function well beyond their warranty period, just with reduced capacity.

Climate plays a role too. Batteries in hot, unventilated garages degrade faster than those installed in cool, shaded locations. A well-installed battery in a temperate coastal city like Melbourne or Hobart will generally outlast the same unit sitting in a Colorbond shed in western Sydney.

Battery degradation is gradual. There's no single moment where it “dies.” Instead, you'll notice a slow decline in performance over several years. Here's what to watch for.

Australia's home battery market really took off around 2018 to 2020, driven by falling lithium prices, the Tesla Powerwall hype, and state rebate programs in Victoria and South Australia. Those early adopters are now 6 to 8 years into their battery's life.

For most of them, the battery is still functioning. But some are starting to notice the signs above, especially those with first-generation products or batteries installed in poor thermal conditions. The first-generation Tesla Powerwall 1, for example, had a 6.4 kWh capacity and a 10-year warranty. People who installed one in 2016 are now approaching or past that warranty window.

This isn't a crisis. It's a normal part of the technology lifecycle. But it does mean that questions about replacement, recycling, and upgrade options are becoming increasingly relevant for a growing number of Australian households.

Expect to pay between $8,000 and $15,000 for a new home battery, depending on the brand, capacity, and whether your existing inverter is compatible. If you need a new hybrid inverter as well, that adds $2,000 to $4,000 to the bill.

One important detail: the federal Small-scale Technology Certificate (STC) rebate can only be claimed once per property for battery installations. If you used it when your original battery was installed, you cannot claim it again for the replacement. Some state-level rebates may still be available depending on your location, so it's worth checking what's on offer through our rebate eligibility quiz.

The removal and disposal of the old battery is usually included in the installation quote, but ask explicitly. Some installers charge separately for disconnecting and removing the old unit.

Yes, and this is actually one of the silver linings of reaching end of life. Battery technology has improved significantly since the early residential installs. A replacement battery purchased today will likely offer more capacity, better efficiency, longer cycle life, and a longer warranty than what you originally had.

If you originally installed a 5 kWh or 6.4 kWh battery, you might now choose a 10 kWh or 13.5 kWh replacement. Your energy needs may have changed too, perhaps you've added an electric vehicle, a pool pump, or a heat pump hot water system. A larger battery makes sense if your household load has grown.

You may also find that the new battery uses LFP chemistry instead of NMC. LFP batteries have become the dominant choice for residential storage because they handle more charge cycles, tolerate heat better, and have a longer overall lifespan. They're slightly less energy-dense, but for a wall-mounted home battery, that trade-off is well worth it.

The key consideration is inverter compatibility. If your existing hybrid inverter supports the new battery brand, the swap can be straightforward. If not, you may need to replace the inverter as well, which adds to the cost but also gives you access to the latest features and efficiency improvements.

This is worth emphasising because it's a common concern. If your battery degrades or even fails completely, your solar panels and inverter continue to operate normally. You keep generating free electricity during the day. You keep exporting surplus to the grid and receiving your feed-in tariff.

What you lose is the ability to store that daytime solar for evening use. You go back to exporting during the day at a low rate and buying from the grid at a higher rate in the evening. It's not ideal, but it's not a catastrophe either. Solar panels have a design life of 25 to 30 years, so your panels should have plenty of life left even when the battery needs replacing.

One of the legitimate concerns about battery storage has always been what happens at end of life. The good news is that Australia's battery recycling infrastructure has matured significantly in recent years.

If your battery is approaching the 7 to 10 year mark, or you're noticing any of the degradation signs mentioned above, here's a practical approach.

First, check your monitoring app for the State of Health reading. If it's above 70%, you likely have several more years of useful life. Keep monitoring it annually. If it's below 70%, start planning for a replacement within the next 12 to 24 months.

Second, check your warranty status. If you're still within the warranty period and the battery has dropped below the guaranteed capacity threshold (usually 70 to 80%), contact the manufacturer or your installer to file a claim. You may be entitled to a replacement or repair at no cost.

Third, get quotes from a couple of installers. The battery market has become more competitive, and prices have dropped. What you paid in 2018 for a 10 kWh battery might now get you 13.5 kWh with better chemistry and a longer warranty. Compare your options using our battery comparison tool.

Finally, check available rebates. Even though the federal STC may not be available for a second battery install on the same property, state programs change regularly. Our rebate quiz can help you find what's currently on offer in your state.