Solar Batterry Comparion in Australia 2025 & What Solar Battery Size Do You Really Need?
With electricity prices rising and Australia’s battery rebate launching nationally in 2025, solar storage is hotter than ever. But while brands like Tesla, BYD, and Sungrow dominate the headlines, one question still stumps most homeowners: what solar battery size do I need for my house? This article builds on our 2025 YouTube video, “🔋 Solar Batteries in Australia 2025 (Full Comparison) | Tesla vs BYD vs Sungrow and more,” and dives deeper into how to choose the right battery size for your needs.
Why Solar Battery Size Matters
Choosing the right solar battery size is critical to:
- Maximise savings on your energy bill
- Ensure you have enough backup power during blackouts
- Avoid overpaying for unused capacity
A battery that’s too small won’t meet your energy needs. Too big, and you’ll stretch your budget without added benefit. That’s why using a solar battery size calculator or working with a battery installer who understands your home energy profile is essential.
How to Calculate the Ideal Solar Battery Size
To determine the right solar battery size for your home, consider these factors:
1. Your Daily Energy Usage
Check your energy bill to find your average daily usage in kilowatt-hours (kWh). For most Australian homes, this ranges from 10 to 30 kWh/day.
Low usage: 5–10 kWh/day
Medium usage: 11–20 kWh/day
High usage: 21+ kWh/day
2. How Much Solar You Generate
Look at your solar system output. If you produce more than you use during the day, a battery can store that excess for night-time use.
5 kW solar = ~20 kWh/day
6.6 kW solar = ~25 kWh/day
10 kW solar = ~40 kWh/day
3. Your Backup Power Needs
Do you want:
Partial backup (just essentials like fridge, WiFi, lights)?
Full-home backup?
Most Australians opt for 10 to 15 kWh batteries for partial backup, and 13.5 to 20+ kWh for full home coverage.
4. Solar Battery Size Calculator Tools
Use online tools like our solar battery calculator
These help estimate what size battery suits your usage, feed-in-tariff, and solar export levels.
Real-World Examples from the Top Brands in 2025
Here’s what different systems offer in terms of solar battery sizes:
📱 Tesla Powerwall 3
Size: 13.5 kWh
Best for: Whole-home backup or pairing with 6.6–10 kW solar
Notes: High output (11 kW), not modular, premium price
🌟 BYD Battery-Box HVM
Size: 8.3–66 kWh (modular)
Best for: Homes with high usage or needing flexible expansion
Notes: Compatible with Fronius, SMA, Victron
⚡️ Alpha ESS Smile5
Size: 5.7 to 33.2 kWh (modular)
Best for: Budget-conscious families with partial backup needs
Notes: Built-in inverter, affordable, entry-level support
🏡 RedEarth Troppo / BlackMax
Size: 10 to 60+ kWh
Best for: Off-grid or rural homes
Notes: Aussie-made, pre-wired cabinets
💡 Growatt ARK
Size: 10.2 to 25.6 kWh
Best for: Entry-level buyers wanting scalable storage
Notes: Works with Growatt hybrid inverter only
🌿 Sigenergy Sigenstor
Size: 5 to 48 kWh
Best for: Tech-savvy homeowners or those with EV chargers
Notes: All-in-one smart system with EV integration
🔋 Sonnen Evo
Size: 10.5 kWh
Best for: Premium buyers wanting longevity (10,000 cycles)
Notes: German made, sleek but non-modular
What Size Solar Battery Do I Need for My House?
Here’s a simple table to guide you:
Daily Usage (kWh)
Recommended Battery Size
Backup Type
5–10
5–10 kWh
Essentials only
11–20
10–15 kWh
Essentials + lights
21+
13.5–25+ kWh
Full-home backup
Tip: If your goal is return on investment (ROI), a battery that covers evening and early morning usage is usually ideal.
Other Considerations When Choosing Battery Size
Modular systems allow you to start small and expand
Hybrid vs AC-coupled may affect sizing flexibility
Single-phase vs three-phase: not all batteries suit all setups
Warranty cycle limits: 6,000 cycles is industry standard
Rebates: Some state rebates cap the maximum battery size eligible
Final Thoughts
Choosing the right solar battery size is one of the most important parts of your solar journey. Get it right, and you’ll maximise both your savings and your home’s resilience. Use a solar battery calculator, think through your goals, and match your home with one of the systems we reviewed in our 2025 YouTube comparison of Tesla vs BYD vs Sungrow and more.
Got questions or want a custom quote? Use our free battery size calculator or comment on the video – we’re here to help.
Watch the full breakdown of solar battery sizes in our 2025 comparison video here or try our Solar Battery Size Calculator Tool to get started today.
