Solar battery warranty comparison: years, cycles and throughput

Which home battery brands guarantee the highest end-of-warranty capacity retention percentage after 10 years of daily cycling?

Among the series in this table with a verified year-10 retention figure in their manufacturer warranty documents, the highest is 80%: sonnen (sonnenBatterie eco) and SolarEdge (Home Battery). Tesla Powerwall, Sungrow SBR/SBH, SolaX Triple Power and Sigenergy SigenStor sit at 70%, and BYD's Battery-Box Premium series at 60%. Across the wider catalogue our CEC product-data tracking covers, iStore's IS-BATT range also documents 80% at year 10. We don't have a verified retention percentage for the remaining series on this page — those rows show 'Not published' rather than an estimate.

Which home battery brands offer a warranty with unlimited cycles rather than a fixed total energy throughput limit?

Tesla Powerwall is the standout in our data: its AU/NZ warranty documents unlimited cycles under solar self-consumption, with a 37.8 MWh throughput cap only applying to heavier use such as VPP or arbitrage cycling. Sigenergy SigenStor is throughput-based rather than cycle-limited (70% usable-energy retention or its published throughput cap, whichever comes first) — no fixed cycle count either. Every other series we track publishes a fixed cycle cap (typically 4,000-10,000 cycles), a total-energy throughput cap (15-40 MWh), or both.

Does the Sigenergy SigenStor have a good warranty?

SigenStor carries a 10-year warranty from Sigenergy, warranted to 70% usable-energy retention or a published throughput figure (26.68 MWh for the BAT 10.0 module), whichever comes first — a throughput-based structure rather than a fixed cycle count. That puts it in line with the longer-running brands in our catalogue on warranty length. Note that SigenStack is a different Sigenergy product line with its own warranty document and different retention terms — check the document for the specific product you're quoted.

What's the difference between a cycle limit and a throughput limit on a battery warranty?

A cycle limit counts full charge/discharge cycles (e.g. 6,000 cycles) regardless of how much energy each cycle moves. A throughput limit instead caps the total lifetime energy the battery can push through, measured in megawatt-hours (MWh) — so a battery that's only ever partially cycled can still use up its throughput allowance faster than the cycle count would suggest, and vice versa. Some warranties combine both and apply whichever limit is reached first; others use only one.

How long is a typical home battery warranty in Australia?

Across the 22 series we track, 10 years is the standard term - every series in our data carries at least a 10-year warranty, and Enphase's IQ Battery is the outlier at 15 years. Warranty length alone doesn't tell the whole story though: check the cycle or throughput cap and any end-of-warranty capacity guarantee alongside the number of years.