Australia’s residential battery market is experiencing a sharp transformation. Thanks to the new federal battery rebate, battery sales are booming — and reshaping both what customers buy and how much they spend.
For the first time ever, battery system sales in May exceeded PV system sales, a dramatic signal of shifting priorities among solar customers. But it’s not just the number of installations that’s changing — battery sizes, price-points, and customer strategies are evolving fast, as a revealed by content drawn from SunWiz’s battery market intelligence subscription.
Customers Are Buying Bigger Batteries
Driven by the once-off nature of the federal battery rebate, consumers are making the most of their opportunity — by buying the largest battery they can reasonably afford.
Battery sizes in the 20–30kWh range saw a 191% increase in sales in May compared to the previous month, making it the fastest-growing segment. Other size bands — including 10–15kWh, 15–20kWh, 30–40kWh, and 40–50kWh — also more than doubled in volume .
At the same time, the market for very large batteries (100–200kWh) has slowed significantly, likely due to their ineligibility for the federal rebate.
Price-Per-kWh Is Falling — Even As Total Spend Rises
Despite larger battery sizes, customers are paying less per kilowatt-hour than ever before.
The median price for residential ESS-only (retrofit) batteries has fallen from ~$1100/kWh to around $1000/kWh. In some cases — especially for larger systems — unit costs are significantly lower than this. Yet, total customer spend is rising, because battery sizes are increasing.
In short: customers are getting more storage for their money — and spending more overall to secure that value.
Economies of Scale Are Driving Better Value
Part of the falling unit cost story is about scale. Larger batteries are inherently cheaper per kWh, thanks to more efficient installation and system integration.
For example:
- A sub-10kWh battery may cost ~$1300/kWh
- A 30–50kWh system may come in under $850/kWh
- The median price for all systems is now just above $1017/kWh, with the lowest brackets falling rapidly
SunWiz’s pricing heatmaps and historical trendlines show this clearly: the bigger the system, the better the $/kWh outcome.
Small Batteries Are Getting Cheaper Too
While economies of scale explain part of the pricing trend, the decline in battery prices is occurring across the board — including in smaller systems.
This points to another factor at work: competitive pricing pressure.
SunWiz market data reveals:
- A broad-based price reduction across all but the largest size brackets
- Especially sharp price drops among brands with lower market share, who tend to price higher
- Two of the top three brands have significantly dropped prices, increasing pressure on competitors
- One particularly low-cost brand is reshaping expectations in the entry-level segment
A Better Deal for Customers — and a Changing Market for Suppliers
As a result of these trends:
- Customers are spending more (by upsizing)
- But getting better value (lower cost per kWh)
- The federal subsidy is working — stimulating demand, reducing cost per kWh, and driving innovation
- Suppliers must now compete not just on capacity, but on value, flexibility, and retrofit readiness
Final Word
The battery rebate is doing more than stimulating demand — it’s changing what people buy, how much they spend, and how they think about value. With the federal rebate only just about to start, now is the time for manufacturers, distributors, and retailers to act on these insights.
