Solar & Battery Guide

The right system size depends on your electricity bill, how much power you use during daylight hours, and your roof space. As a rough guide:

• Under $200/quarter: 6.6kW is usually sufficient
• $200-$400/quarter: 10-13.2kW will cover most of your usage
• Over $400/quarter or large home: 13.2kW+ or a split system may be appropriate

The most common residential system in Australia is 6.6kW of panels with a 5kW inverter. This combination is popular because STCs (rebates) are calculated on 6.66kW and a 5kW inverter is the largest single-phase unit most homes can accommodate.

Generation depends on your location. Average daily generation for a 6.6kW system:

• Queensland (Brisbane): 26-28 kWh/day
• NSW (Sydney): 24-26 kWh/day
• Victoria (Melbourne): 20-23 kWh/day
• South Australia (Adelaide): 24-27 kWh/day
• Western Australia (Perth): 26-29 kWh/day

Remember: solar only generates during daylight. If you're mostly home during the evening, a battery becomes more important for self-consumption.

Battery storage has become more affordable, but whether it's worth it depends on your situation:

• Good fit for batteries:
• Large evening electricity usage
• Frequent or long power outages in your area
• Time-of-use tariff with high peak rates
• EV owner wanting home charging from solar
• Feed-in tariff dropped significantly (under $0.06/kWh)

• Battery may not add value if:
• You're mostly home during the day and self-consume most solar
• Your feed-in tariff is still reasonable (above $0.08/kWh)
• Your grid is reliable and outage protection isn't a priority

A typical 10kWh battery system lands between $8,550 and $10,925 installed, after the federal battery discount. Rebates make a meaningful difference here, which is why the federal discount and any state program matter so much when you're weighing one up. Ray will give you the range for the size that actually suits your place.

Based on industry track record and warranty terms:

• Tier 1 (most recommended):
• Tesla Powerwall 3: 13.5kWh, strong warranty, excellent software, premium price
• BYD Battery-Box: Multiple capacity options, LFP chemistry, solid track record
• Sungrow SBR: Good value, widely installed, reputable brand
• Sigenergy SigenStor: Modular all-in-one, strong local support, growing fast in Australia

• Also well-regarded:
• Enphase IQ Battery (AC-coupled, modular)
• FIMER/ABB (commercial focus)
• GoodWe Lynx (value range)

Things to check: Warranty duration (10 years minimum), cycle warranty (at least 6,000 cycles or 80% retention), chemistry (LFP is safer and longer-lasting than NMC), and whether the brand has an Australian service presence.

• String inverter (most common):
• One central inverter converts DC from all panels to AC
• Cheapest option, simpler to service
• Weakness: shading on one panel affects the whole string
• Best for: unshaded, north-facing roofs

• Microinverters (Enphase):
• One small inverter per panel
• Each panel operates independently - shading doesn't affect others
• More expensive, harder to service individual units
• Best for: complex roofs, partial shading, east/west splits

• String + optimisers (SolarEdge):
• String inverter with DC optimisers on each panel
• Middle ground: panel-level monitoring, shade tolerance
• Popular for roofs with some shading or multiple orientations

Reliable inverter brands: Fronius, SolarEdge, Enphase, Sungrow, Sigenergy. Avoid heavily discounted no-name brands - inverters typically last 10-15 years and the warranty and support matter.

STCs are the main federal solar rebate. They reduce the upfront cost of your system and are typically already applied as a discount by your installer.

• How they work:
• Calculated based on system size and your location's solar rating zone
• A 6.6kW system in Brisbane typically attracts $2,500-$3,500 in STC value
• Larger systems and sunnier locations receive more
• The rebate reduces as the scheme winds down toward 2030 - current year gets the full amount

Important: You must use an SAA-accredited installer to access STCs. Always confirm your installer holds current SAA (Solar Accreditation Australia) accreditation.

State programs change often and funding can run out, so treat these as a starting point and confirm with your installer:

• Queensland: No state solar or battery rebate. The Battery Booster program closed in May 2024 and has not been replaced. The federal programs are the only support.
• New South Wales: Home Energy Saver 0% loan of $2,000 to $15,000 (household income up to $210,000), plus roughly $720 to $1,500 under the Peak Demand Reduction Scheme for connecting a battery to a VPP.
• Victoria: Solar Homes rebate of up to $1,400 on solar, with an interest-free loan option. Household income up to $150,000. No current battery rebate.
• South Australia: A VPP battery incentive is open to priority households only (pensioners, health care card holders and some renters).
• Western Australia: Residential Battery Scheme rebate of up to $1,300 (Synergy) or $3,800 (Horizon Power), which requires joining a VPP, plus a 0% loan option.
• ACT: Sustainable Household Scheme 3% loan of up to $20,000 for batteries. It does not cover the panels.
• Tasmania and NT: No current state scheme.

The quality of your installation matters as much as the quality of the components. A premium panel fitted poorly will underperform a mid-range panel installed correctly.

• Non-negotiable requirements:
• SAA Accreditation: Solar Accreditation Australia (SAA) is the body that accredits solar and battery installers in Australia - it took over installer accreditation from the Clean Energy Council in 2024. It is the baseline standard and is required to access STCs. Verify your installer at solaraccreditation.com.au
• Licenced electrical contractor: In all states, solar installation must be done by or supervised by a licenced electrician
• Proper insurance: Public liability and professional indemnity

• Quality indicators:
• Uses Tier 1 panels and reputable inverter brands
• Provides a detailed written quote specifying brand, model and specs
• Explains how your system was sized for your usage
• Offers monitoring access (app or portal)
• Clear warranty terms on workmanship (not just equipment)

1. Unusually low prices A fully installed 6.6kW system below $3,500-$4,000 is almost certainly cutting corners on components, installation quality, or both. The STC rebate is already in this price - it's not an additional saving.

2. No specification of brand and model If a quote doesn't name the exact panel model, inverter brand and battery model, ask for it in writing. Vague quotes allow component substitution after acceptance.

3. Pressure to decide immediately "This price is only valid today" is a sales tactic. Reputable installers don't use high-pressure closing tactics.

4. No SAA accreditation Ask for the installer's SAA (Solar Accreditation Australia) accreditation number and verify it. Unaccredited installers cannot access STCs - meaning you pay a higher price AND lose the rebate.

5. Promises of specific savings figures No installer can guarantee bill savings - too many variables. A reputable installer will give you estimates, not guarantees.

6. No Australian warranty support Some cheaper products have overseas-only warranty support. Ask: "If the inverter fails in 5 years, where do I take it?"

7. Subcontracting without disclosure Ask if the company's own employees will install the system, or if it'll be subcontracted. Both can be fine - but you deserve to know, and the subcontractor must also hold SAA accreditation.