The spec sheet, side by side
Tesla Powerwall 3
- Usable capacity: 13.5 kWh
- Continuous power: 11.5 kW (impressive - runs an entire home easily)
- Inverter: Built-in hybrid solar inverter (3 MPPT inputs, 20 kW PV)
- Warranty: 10 years, 70% capacity at end of warranty
- Typical installed price (WA): $13,500 – $15,500
- App: Best in class
- Backup: Whole-home, automatic
- Stack to expand: Yes, up to 4 units (54 kWh)
Sungrow SBR (most common: SBR096 or SBR128)
- Usable capacity: 9.6 kWh or 12.8 kWh (modular)
- Continuous power: 5–7.6 kW (depends on inverter pairing)
- Inverter: Separate Sungrow SH-RS hybrid inverter required
- Warranty: 10 years, 60% capacity at end
- Typical installed price (WA): $11,500 – $13,500
- App: Decent, less polished than Tesla
- Backup: Selected circuits, optional whole-home with extra hardware
- Stack to expand: Yes, modular 3.2 kWh blocks up to 25.6 kWh
BYD Battery-Box Premium HVS / HVM
- Usable capacity: Modular - 5.1, 7.7, 10.2, 12.8 kWh (HVS) or up to 22.1 kWh (HVM)
- Continuous power: Inverter-limited (depends on pairing - usually 5–8 kW)
- Inverter: Separate; commonly paired with Fronius, GoodWe, or SolaX
- Warranty: 10 years, 60% capacity at end
- Typical installed price (WA): $10,500 – $13,000
- App: Depends on inverter brand
- Backup: Selected circuits, depends on inverter
- Stack to expand: Yes, very modular
What the numbers don't tell you
Powerwall 3 - the polished pick
Tesla has spent more on the Powerwall 3 user experience than the other two brands combined. The app actually works, software updates roll out automatically, and the whole-home backup is genuinely automatic - when the grid drops, the lights flicker for under 100ms and the house is on battery.
The catch: lead times. Tesla install windows in WA can stretch to 6–10 weeks because demand outstrips supply. If you want it before next summer's bills hit, lock in the install date now.
Best for: Households that want a "set and forget" battery, plan to keep the home long term, value monitoring/app experience, or want whole-home backup without fiddling with circuits.
Sungrow SBR - the value pick
Sungrow has quietly become the workhorse of Australian rooftop solar. Their SBR battery line pairs with their hybrid inverters to deliver excellent reliability at 15–20% under Tesla pricing. The modular design means you can start at 9.6 kWh and add more later if your needs grow (an EV, an electrification project, more occupants).
The catch: the app and software ecosystem isn't as polished as Tesla's. Some installers report occasional firmware quirks, though Sungrow's been quick to push fixes. Selected-circuit backup is less convenient than whole-home.
Best for: Pragmatic buyers, households planning to scale storage over time, anyone wanting Tier 1 reliability without the Tesla premium.
BYD Battery-Box Premium - the budget pick
BYD makes the cells. The Battery-Box Premium is the chassis. The inverter is whatever your installer pairs it with - usually Fronius (premium European), GoodWe (mid-tier), or SolaX (budget). This decoupled approach is what makes BYD the cheapest path to a Tier 1 battery in WA. You also get exceptional modularity: start with 5 kWh, scale to 22 kWh on the same chassis.
The catch: total system experience depends heavily on which inverter the installer chose. A BYD paired with Fronius is excellent. A BYD paired with cheap unknown-brand inverters can be a maintenance nightmare. Ask your installer specifically which inverter they're quoting, and verify it's a brand with strong WA service support.
Best for: Price-sensitive buyers, people who'd rather upgrade their solar inverter and add a battery as one combined job, anyone who wants tight control over which inverter brand is used.
The price reality check
After the WA state rebate ($5,000 Synergy / $7,500 Horizon) and federal Cheaper Home Batteries rebate (~$5,000 for a 13.5 kWh system), here's what a Perth Synergy household actually pays out of pocket for each option installed (mid-range pricing):
- Powerwall 3 (13.5 kWh): ~$14,000 list → ~$4,000 after rebates
- Sungrow SBR128 (12.8 kWh): ~$12,500 list → ~$2,800 after rebates (state rebate slightly smaller because battery is smaller)
- BYD HVS 12.8 kWh + Fronius inverter: ~$11,800 list → ~$2,100 after rebates
That's a $1,900 gap between the cheapest and most expensive option, post-rebate. For some households the Tesla experience is worth $1,900. For others, the BYD's flexibility and savings are.
Which one should you get?
The honest answer: it depends less on the battery and more on your installer. A great installer can make a Sungrow feel as smooth as a Powerwall. A weak installer can make a Powerwall feel like a science project. Pick the installer first, then take their recommendation between the three. All three are SAA-approved, all three carry 10-year warranties, all three are Tier 1.