Don’t Buy a Home Battery Until You Ask These Questions
A quality installer will start with data, not guesswork. Ask: “Based on my interval meter data, what usable capacity do I need and why?” Sizing should account for your overnight consumption, seasonal solar generation, and any planned changes, like charging an EV on off-peak rates.
Follow up with “Is my PV array large enough to recharge the battery year-round?” If exports already fall short on winter days, you may need extra panels or a higher-efficiency module such as an AIKO N-type option to meet daily demand and still claim STCs.
Finally, clarify backup expectations. “Which circuits will stay on during an outage, and for how long?” Some batteries provide whole-of-home backup; others run a protected load sub-board.
Knowing the kW output limit avoids disappointing surprises when the kettle trips the system during a blackout.
Check chemistry, safety, and scalability
Chemistry drives safety, lifespan, and cost. Lithium-iron-phosphate (LFP) dominates new residential sales because it resists thermal runaway and tolerates deeper daily cycling, crucial for Australian summer heatwaves. Nickel-manganese-cobalt (NMC) units pack more energy per kilogram but may need stricter temperature management.
Ask the installer: “Why have you chosen this chemistry for my site?” Expect a clear explanation of thermal performance, warranty depth-of-discharge limits and round-trip efficiency.
If you plan to electrify a pool heat pump or EV later, scalability matters. A modular design, such as Sigenergy’s SigenStor, expandable from 10 kWh to 48 kWh in 5 kWh blocks and managed by in-built AI energy optimisation, lets you add capacity without replacing the whole stack. Confirm whether expansion retains the original warranty and whether extra modules need DNSP re-approval.
Confirm your installer’s credentials
Under Australian law, only Clean Energy Council (CEC) or Solar Accreditation Australia (SAA) accredited electricians with the Battery Storage endorsement (grid-connected) may sign off residential installs. Politely request their accreditation number and verify it on the public register— an easy test of transparency.
Experience counts too. “How many home battery systems have you installed in the past 12 months, and can I speak to a recent customer?” A seasoned team will have refined processes for DNSP connection, meter re-configuration and emergency shutdown labelling under AS/NZS 5139.
Pin down warranty and performance guarantees
Most premium batteries promise 10 years or a specified energy throughput—whichever comes first. Drill into the details:
- Usable vs nominal capacity: If a 15 kWh battery offers 90 % depth of discharge, only 13.5 kWh is available each cycle.
- End-of-warranty state-of-health: 70 % retained capacity is common, but some brands guarantee 80 %.
- Labour and freight: A product warranty that excludes installation costs can leave you hundreds out of pocket.
- Inverter warranty alignment: When using an AC-coupled option like Sungrow’s SBH range on an existing PV inverter, match both warranties to avoid gaps.
A credible installer will supply the full manufacturer warranty booklet, not just a spec-sheet snippet, so you can confirm these points in writing.
Understand the installation requirements
Battery safety hinges on correct location, clearances, and protection. AS/NZS 5139 forbids wall-mounting lithium systems on shared habitable walls unless additional fire-resistant barriers are applied. Ask:
- “Where exactly will the enclosure sit, and how will you comply with the required ‘fire safety zones’?”
- “Do we need bollards to protect against vehicle impact in the garage?”
- “Will the site preserve natural ventilation and stay below the battery’s temperature limits?”
Request an as-built wiring diagram and an Electrical Safety Certificate on handover. These documents are vital for insurance and future servicing.
Get the full financial picture
Quotes should be fixed-price and itemised: hardware, switchboard upgrades, smart meter, labour, DNSP fees, and GST. Probe the savings model:
- Tariff assumptions: Electricity prices and feed-in tariffs vary by retailer. Ask the installer to run scenarios for both flat and time-of-use rates.
- Battery degradation: A 2 % annual capacity loss can erode returns; responsible forecasts include it.
- Government incentives: From July 2025, the Cheaper Home Batteries Program will discount upfront costs. State schemes—like the SA Home Battery Scheme or Victoria’s Solar Homes battery rebate—may add further savings. Confirm the installer will lodge paperwork and that your chosen product is on the eligible list.
If capital outlay is a barrier, compare green loans to vendor finance. Low-interest green loans often work out cheaper than deferred-payment plans bundled with hardware.
Ask about monitoring, support, and future flexibility
Modern hybrid inverters—Sungrow, SolarEdge, Enphase, and Sigenergy among them—provide cloud dashboards showing solar generation, consumption, and state-of-charge in real time. Request a live demo and written access instructions.
Clarify service pathways. “If the battery flags an error, do I call you, the inverter helpline, or the manufacturer?” An installer-backed hotline streamlines support and protects against finger-pointing.
Finally, explore grid services. Many units are Virtual Power Plant (VPP)-ready. Participating can earn an annual credit but may increase the cycle count. Discuss how VPP operation affects warranty cycles and whether you can exit the program without penalty.
Keep sustainability in focus
Ask manufacturers about recycled content, ISO 14001 certification, and end-of-life take-back schemes. While large-scale lithium recycling is still ramping up in Australia, some brands are partnering with recyclers like Envirostream to recover valuable metals. If a mature scheme exists, note the process and any future costs.
Tree removal for ground-mounted banks should be a last resort; explore shade structures or slimline wall units first. Where removal is unavoidable, specify re-planting to offset the ecological impact.
Conclusion: confidence through informed questions
Home batteries promise resilience and lower bills, but the technology’s value hinges on choosing the right product, installer, and operating strategy. By asking the focused questions above and expecting clear, written answers, you ensure the system:
- matches your energy habits and future plans,
- complies with Australian safety and wiring standards,
- delivers realistic financial returns, and
- comes with robust, local support for the decade-plus lifespan.
Take time to compare at least two accredited quotes and read every warranty clause. If you’d like independent guidance or vetted installer referrals, Your Energy Answers can connect you, free of charge, to reputable professionals who will navigate the paperwork and set you on the path to energy independence.
