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Solar + battery

A solar and battery system combines rooftop panels with a home battery. The panels supply the home during the day, spare solar charges the battery, and the battery supplies the home later, typically in the evening.

Designing both together lets the panel size, inverter and battery be chosen to work as one system. Whether it suits you depends on your usage pattern, roof, electricity plan, network rules and whether you want backup.

What it can do for you

  • Use more of your own solar electricity across the day and evening.
  • Choose equipment that works together from the start, such as a hybrid inverter.
  • Optionally include backup for selected circuits, if the system is designed and configured for it.

How it works

How rooftop solar electricity flowsSolar panels produce DC electricity. The inverter converts it to AC, capped at the inverter's AC rating. The home uses solar first. Any surplus is exported to the grid, within any export limit; any shortfall is imported from the grid.Solar panelsArray rating: kW DCInverterDC → AC, kW AC capYour homeUses solar firstGridImport / exportDCACSurplus out (export)Shortfall in (import)Output above the inverter's AC rating is clipped.Export limits may curtail surplus.
AC-coupled and DC-coupled home batteries comparedLeft: an AC-coupled battery has its own battery inverter and joins the solar inverter on the household AC side; it is often simpler to add to existing solar, but stored solar goes through an extra conversion. Right: a DC-coupled battery shares a hybrid inverter with the panels on the DC side; it has fewer conversions and some designs can store solar that would otherwise be clipped, but retrofitting may mean replacing the inverter. Neither is always better.AC-coupledSolar panelsBatteryDCSolar inverterBattery inverterSwitchboardAC: home + gridOften simpler to add to existing solar.Stored solar: DC → AC → DC → AC.DC-coupledSolar panelsBatteryDCHybrid inverterSwitchboardAC: home + gridFewer conversions; may store clipped solar.Retrofit may mean replacing the inverter.
Technical details
Hybrid inverter (DC-coupled) design
A single hybrid inverter connects both the panels and the battery on the DC side. It reduces the number of conversions and some designs can store solar energy that would otherwise be clipped by an oversized array. It ties the panels and battery to one inverter, which affects future upgrades and warranty arrangements.
Separate inverters (AC-coupled) design
The panels have a solar inverter and the battery has its own battery inverter, both on the AC side. This is flexible and often used when adding a battery to existing solar, at the cost of an extra conversion step for stored solar energy.
Sizing the parts together
The panel array (kW DC), the inverter (kW AC), the battery's usable energy (kWh) and the battery's power (kW) are separate design choices. Oversizing the array relative to the inverter is common, but the limit depends on the manufacturer, your network and any scheme rules — there is no single ratio for every home.
Export limits and charging
With a low export limit, a battery can store solar that would otherwise be curtailed. Whether that adds much value depends on how often the battery would be full anyway.
Backup
Backup is a design option, not a default. It needs backup-capable equipment, a safe way to isolate the home from the grid, selected backup circuits and a charge reserve.

Terms people often mix up

Array size (kW DC) vs inverter size (kW AC)
Panel capacity can exceed inverter capacity; output at any instant is capped by the inverter.
Installed vs usable battery capacity (kWh)
Usable capacity is the energy you can actually draw, usually less than the nominal figure.
Battery power (kW) vs energy (kWh)
Power limits how much the battery can supply at once; energy limits for how long.
Gross generation vs self-consumption
Adding a battery raises the share of generation you use yourself; it does not increase how much the panels produce.
Grid import vs total consumption
Solar and a battery reduce grid import. Total consumption stays about the same, or rises slightly because of battery losses.

Advantages and limitations

Advantages

  • Advantage: Equipment chosen to work together, with one design and often one monitoring app.
  • Advantage: Uses spare solar in the evening rather than exporting it for a lower credit.
  • Advantage: Can store some solar that would otherwise be curtailed by an export limit or clipped by the inverter (design dependent).
  • Advantage: Backup for selected circuits is possible when designed for it.

Limitations

  • Limitation: A larger upfront purchase than solar alone, and the value of the battery part varies widely between homes.
  • Limitation: In winter there may be little spare solar to charge the battery.
  • Limitation: A single hybrid inverter is a single point of failure for both solar and battery.
  • Limitation: Backup is not automatic; it needs specific equipment and a reserve.
  • Limitation: Battery capacity declines with age, and warranties have conditions.

Financial considerations

1. Quick estimate

Your postcode, yearly use, the solar and battery sizes and their quoted prices, and the rates from your bill are enough for a first estimate.

Everything is calculated in your browser. Nothing you type here is sent to PlaceNest or anyone else, and you don't need an account. Fields marked as required are needed for the estimate.

Your home & usage

A recent electricity bill has everything this section needs.

Your home's 4-digit postcode — used to estimate sunshine and to find programs for your state or territory.

How would you like to tell us your electricity use?

Your retailer's app or bill may show it; or multiply the bill's 'average daily use' by 365. Main meter only — leave out a separately metered controlled load (e.g. off-peak hot water).

Your solar, battery & quote

From the installer's quote and the battery data sheet.

The total panel rating (DC) on the quote, e.g. 6.6 kW.

The solar panels and inverter only, including GST. Ask the installer to itemise it.

The usable (not nominal) capacity on the data sheet or quote.

Continuous charge / discharge power from the data sheet, e.g. 5 kW.

On the quote or data sheet.

The battery (and any extra equipment it needs) including GST, after any discount already applied.

Your tariff

Copy these from your bill or your retailer's plan details (the “energy fact sheet”), then tell us whether they include GST. We never fill in a price for you.
Your tariff type

Your bill says whether you pay one price all day or different prices at different times.

On your bill as “usage”, “general usage” or “anytime”, in c/kWh.

On your bill as “supply charge” or “daily charge”, in c/day.

What your retailer pays for solar you export (“feed-in tariff”), from your bill or plan. Enter 0 if you have none.

Do the rates you typed include GST?

Many bills print each rate WITHOUT GST and add GST in its own column (look for a “GST” column next to “Amount”). Choose that option and we add 10% to the usage and supply rates — never to the feed-in rate, which has no GST.

PlaceNest assumptions in use — change in Customise: Usage pattern: Most use in the late afternoon and evening · Heating and cooling: No big seasonal change · Panels face: North · Roof tilt: 20° · Shade: No shade · Inverter size: the same as the panel size.

2. Your estimated results

Fill in the quick estimate and press Calculate. Your estimate appears here — it stays in this browser.

3. Customise — detailed settings (optional)

Every setting below already has a value the estimate can use. Open a section to check it against your bill, quote or data sheet — anything you type replaces the PlaceNest assumption or modelling default.

Electricity tariff details (time-of-use times)

Only needed for a time-of-use tariff: choose “Time of use” in the quick estimate, then set your peak, shoulder and off-peak times here. Your usage, supply and feed-in rates and the GST question are in the quick estimate.

Usage pattern
When and how you use electricity changes how much solar or stored energy you use yourself.

This picks an estimated daily pattern. Your real pattern changes how much solar you use yourself. Left on the PlaceNest assumption, we use “most use in the late afternoon and evening”.

Electric heating or air-conditioning shifts use between seasons. Left on the PlaceNest assumption, we use “no big seasonal change”.

e.g. 15 if you'll add electric heating, −10 if you're cutting back. 0 means no change.

Roof orientation & shading
From the installer's design. Left as they are, the PlaceNest assumptions shown are used.

The main roof face. North gets the most sun in Australia. Leave it on the PlaceNest assumption (north) if you're not sure.

Most pitched roofs are about 15–25°; a flat roof is close to 0°. Your installer's design shows it. Leave blank and PlaceNest assumes 20°.

A rough guide only — a site assessment measures real shade. Leave it on the PlaceNest assumption (no shade) if you're not sure.

Panel & inverter details (solar)

The inverter's AC rating on the quote, e.g. 5 kW. Leave blank and PlaceNest assumes the same size as the panels.

Your network may cap how much you can send to the grid (often 5 kW). Leave blank if you don't know.

In kWh per kW per year, if the installer's design gives one (e.g. 1,350). Leave blank to use the official figure for your postcode.

System performance & degradation (solar)
PlaceNest modelling defaults, pre-filled — check the inverter data sheet and the panel performance warranty.

PlaceNest modelling default 97% — check the inverter data sheet.

PlaceNest modelling default 0.5% — check the panel performance warranty.

How the battery runs, backup & VPP
How the battery is run

0 if you don't need backup. Kept charge isn't used to cut your bill.

Only an amount you've actually been offered — we never assume one.

Battery performance, warranty & replacement
PlaceNest modelling defaults, pre-filled — check the battery data sheet and warranty.

Some programs use the nameplate figure.

Energy back out ÷ energy in. PlaceNest modelling default 90% — check the data sheet.

PlaceNest modelling default 5%.

PlaceNest modelling default 2% — check the warranty's end-of-warranty capacity.

From the warranty document. PlaceNest modelling default 10 years.

Optional. Leave it unticked and the results assume the battery keeps working; either way, “What if the assumptions change?” shows the result if it has to be replaced when the warranty ends.

Future price changes
Nobody knows future prices — try other values and compare.

Nobody knows future prices. PlaceNest modelling default 3% — try other values.

Kept separate from electricity prices: feed-in rates have been falling. PlaceNest modelling default 0% (today's rate held).

Incentive eligibility
Optional. Incentives are only taken off the price when PlaceNest has verified the program and you clearly meet its rules.

Programs have date rules. Leave blank to use today.

If your quote shows the price of small-scale technology certificates (STCs), enter it. PlaceNest never assumes a market price.

Most programs require an accredited installer — ask for their accreditation number.

Only some programs have income limits. It stays in your browser.

Finance, maintenance & comparison period
How the money adds up over the years. A loan changes when you pay — it is financing, not a saving.

PlaceNest modelling default: 15 years.

How much less a dollar in future is worth to you than today. PlaceNest modelling default 5%.

Any servicing cost you expect. 0 if none.

Optional. Enter the terms from a real loan offer.

Government incentives & finance

PlaceNest hasn't verified any current government incentives yet, so none are listed here and none are taken off any PlaceNest estimate. Programs change often: check the official government source, and ask your installer what is already included in the quote.

How PlaceNest checks incentives

Is it likely to suit your home?

It may be worthwhile when

  • You do not have solar yet, plan to stay in the home, and use a fair amount of electricity in the evening.
  • Your roof can host enough panels to produce spare solar on most days.
  • Your network export limit is low and you would otherwise lose some solar.
  • You want backup for essential circuits and are prepared to pay for backup-capable equipment.

It may not be worthwhile when

  • Your roof can only host a small array, leaving little spare solar for a battery.
  • Most of your use is during the day, so solar alone already covers it.
  • You expect to move soon or rent the home.
  • A battery would mostly sit partly charged because there is not enough spare solar.

Common misconceptions

Myth: Adding a battery makes the panels produce more.
Reality: A battery changes when you use solar electricity, not how much the panels generate (although some DC designs can recover energy that would otherwise be clipped).
Myth: A solar and battery system always provides blackout backup.
Reality: Only if it is designed with backup-capable equipment and wiring, and only while the battery has charge.
Myth: There is a correct panel-to-inverter ratio for everyone.
Reality: Oversizing is common, but the limit depends on the inverter manufacturer, network connection rules and scheme rules.
Myth: Hybrid (DC-coupled) systems are always better than AC-coupled ones.
Reality: Each has trade-offs in conversions, upgrade flexibility, cost and warranty — the better choice depends on the home.

Checklists

Before you buy

  1. Step 1: Check your interval data or bills for daytime and evening use.
  2. Step 2: Ask for a solar-only option alongside the solar and battery option so you can compare.
  3. Step 3: Compare array size (kW DC), inverter size (kW AC), usable battery capacity (kWh) and battery power (kW).
  4. Step 4: Ask whether the design is AC- or DC-coupled and why.
  5. Step 5: Confirm products are on the Clean Energy Council approved product lists and the installer is accredited with Solar Accreditation Australia.
  6. Step 6: If backup matters, ask which circuits are backed up and how the reserve is set.
  7. Step 7: Compare warranties for panels, inverter, battery and workmanship.
  8. Step 8: Read the contract, payment terms and cooling-off rights before signing.

At installation

  1. Step 1: Network approval is in place before switching on.
  2. Step 2: Battery location meets the manufacturer's and Australian Standard requirements.
  3. Step 3: Backup circuits, if any, are labelled at the switchboard.
  4. Step 4: You receive compliance certificates, serial numbers, warranty registrations and the system settings.
  5. Step 5: The installer demonstrates the shutdown procedure and the monitoring app.
  6. Step 6: Your retailer is told about the system so your meter and plan can be updated.

Safety

Frequently asked questions

Should I install both at once or start with solar?

Either can make sense. Installing together allows a single design; starting with solar and adding a battery later spreads the cost. If you might add a battery later, ask for equipment that supports it.

Is a hybrid inverter required?

No. A hybrid inverter is one way to connect a battery; an AC-coupled battery with its own inverter is another.

How is the battery charged in winter?

From whatever spare solar there is, and on some systems from the grid during cheaper periods. In winter the battery may not fill from solar on many days.

Can I add a battery to the solar I already have?

Often, yes. An AC-coupled battery can usually sit alongside an existing solar inverter; a DC-coupled battery needs a hybrid inverter, which may mean replacing the existing one. Check the age and warranty of the current inverter, product compatibility and network approval with an accredited installer.

Can the system run my whole house in a blackout?

Only if it is designed for whole-home backup, which is limited by the battery's power (kW) and energy (kWh). Many systems back up selected circuits only.

Related topics

Ready to ask for quotes?

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Sources and review

Draft — pending human review

Not yet reviewed by a person. Programs, products and rules change — check the official source before you decide.

General information only. PlaceNest's energy guides, and any estimates or incentive lists, are general information and estimates — not personalised financial advice, and not a quote. Programs, prices and rules change: check the official sources, and get written quotes from accredited installers before you decide.

PlaceNest guides are general information, not financial advice. Whether solar, a battery or an EV charger pays off depends on your home, usage and prices.

Any incentive or finance details PlaceNest shows come from a reviewed list, each with its official source and the date it was checked; eligibility is decided by each program. See how incentives work and paying for an upgrade.

Not sure what size battery?

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