Home battery warranties explained: years, throughput and retained capacity

Quick answer: a home battery warranty usually runs for 10 years and promises the battery keeps a set share of its capacity, commonly 70%, until the term ends or a set amount of energy has passed through it, whichever comes first. FOXESS caps its CQ7 at 141.53 MWh for the 27.84 kWh stack and 212.24 MWh for the 41.76 kWh stack. The conditions, from who installs it to when it is registered, matter as much as the numbers.

A home battery warranty is two promises in one. The product warranty covers faults in the hardware. The performance warranty covers how much capacity the battery keeps as it ages. Both sit on top of your rights under the Australian Consumer Law, and the inverter usually has a warranty document of its own. Here is what to look for in each.

What does a home battery warranty cover?

• Years. Ten is standard on the batteries and inverters we install. The clock generally starts at installation, with a limit counted from the manufacture date, so stock that sat in a warehouse doesn’t gain extra years.
• Retained capacity. A floor, often 70%, that the battery’s capacity shouldn’t fall below during the warranty.
• Throughput. The total energy the battery can deliver under the performance warranty, in megawatt-hours (MWh). Reach it and that cover ends, even if the years haven’t.
• Conditions. Who installs it, where it lives, how hard it works and when it is registered.

Accessories often carry less. GoodWe’s single-phase ESA warranty gives 10 years on the inverter and battery modules but two years on the Wi-Fi/LAN and 4G kits and on its GMK110 and GM330 meters.

Retained capacity: what 70% means in kWh

A 70% guarantee means the battery should still hold at least 70% of its starting capacity until the warranty ends. FOXESS words it as 70% of nominal or usable energy, which on the CQ7 is the same figure because every module is fully usable. GoodWe words it as 70% of usable energy.

The floor is a warranty threshold, not a forecast of how your battery will age.

Throughput caps: how many cycles is that?

Throughput is the total energy a battery delivers over its life. Divide the cap by the usable capacity and you get the number of full charge-and-discharge cycles it allows. Divide that by the cycles you use in a year and you get how many years it lasts. The figures below are our arithmetic, for illustration; “0.6 of a cycle a day” means a home that uses 60% of the battery on an average day.

Cover ends at whichever comes first. On the CQ7, even a battery cycled fully every day reaches 10 years before the throughput cap, so the years are the limit that applies. GoodWe’s single-phase ESA figure works out to one full cycle a day for 10 years, which matches its condition that the warranty covers up to one full cycle a day. At 3 MWh per usable kWh, a battery cycled fully every day would reach the cap in a little over eight years, while one used to 60% a day would reach 10 years first.

Which GoodWe figure applies? GoodWe’s limited warranty for the single-phase ESA (revision 1.0, July 2025) lists 29.20 MWh for the GW8.3-BAT-D-G20 module. GoodWe’s BAT series warranty, which names both the G20 and the GW8.3-BAT-D-G21 used in our packages, sets 3 MWh per kWh of usable capacity, or 24 MWh for an 8.0 kWh module. Ask for the document that lists the exact model codes on your quote.

FOXESS and GoodWe warranty terms compared

What can void a battery warranty?

• The installer. FOXESS excludes installation by a non-accredited installer, and GoodWe requires qualified installers.
• Registration and connection. FOXESS asks for the CQ7 to be registered within 36 months of installation, recommends doing it within six weeks, and requires it to be registered and connected to the FOXESS website at commissioning.
• Where it lives. GoodWe requires a ventilated location out of direct sunlight and excludes damage from sea coasts, saltwater or aggressive atmospheres unless it has approved the site in writing. FOXESS sets an ambient range of −10 to 50 °C and excludes inadequate ventilation and flooding.
• How hard it works. GoodWe’s cover is based on one full cycle a day.
• How quickly you claim. GoodWe sets short deadlines: two weeks from the failure date in its single-phase ESA warranty and one month in its inverter warranty. Report faults promptly.

Location rules from the standards are covered in home battery installation rules.

Workmanship, extended cover and your consumer rights

Manufacturer warranties cover the equipment. The installation is a separate promise: NRGPAL gives its own five-year workmanship warranty on the work we do, set out in our terms and conditions. FOXESS also sells FoxPro, which extends its inverter cover to up to 240 months in total if bought within 36 months of commissioning.

None of this replaces the Australian Consumer Law. As the ACCC puts it, consumer guarantees are automatic and can’t be taken away; warranties are extra promises on top of them. FOXESS and GoodWe both state in their warranty documents that their goods come with guarantees that can’t be excluded under the Australian Consumer Law.

Warranties on the systems we install

Our FOXESS packages pair an H1 G2, KH or H3 Smart inverter with a CQ7 battery, so they carry FOXESS’s 10-year inverter and battery terms: the FOXESS KH8 system with 27.84 kWh sits under the 141.53 MWh cap and the FOXESS KH8 system with 41.76 kWh under 212.24 MWh. Our GoodWe packages, such as the GoodWe ESA 9.99 kW single-phase system with 32 kWh, carry GoodWe’s 10-year terms. The batteries are covered in more depth in our FOXESS CQ7 battery guide and GoodWe 8.3 kWh battery module guide. Build Your System recommends a system for your home; ask us for the warranty documents that match its model codes.

Frequently asked questions

How long is a home battery warranty in Australia?

Ten years is typical for the batteries we install. FOXESS covers its CQ7 for 120 months from installation, capped at 125 months from manufacture, and GoodWe covers its ESA battery modules for 10 years. Within that time, each guarantees at least 70% of the battery’s capacity unless a throughput cap is reached first. The inverters are also covered for 10 years.

What is a battery throughput warranty?

It caps the total energy the battery can deliver while the performance warranty applies, measured in megawatt-hours. The warranty ends when the years run out or the cap is reached, whichever comes first. Divide the cap by the usable capacity to get the number of full cycles it covers: FOXESS’s 141.53 MWh on a 27.84 kWh CQ7 is about 5,080 full cycles.

Does the battery warranty cover the inverter?

It depends on the brand. FOXESS covers its H1 G2, KH and H3 Smart inverters under a separate inverter warranty, 120 months from installation, with a FoxPro extension available. GoodWe’s single-phase ESA warranty covers the inverter and the battery modules together for 10 years, while its three-phase ESA inverters sit under GoodWe’s inverter warranty.

Who do I contact if my battery develops a fault?

Start with your installer. FOXESS’s warranty says the installer contacts FOXESS with the model, serial number, fault code and details, and GoodWe sets claim deadlines measured in weeks, so report a fault as soon as you notice it. NRGPAL customers can contact us directly, and our five-year workmanship warranty covers the installation itself.