“I will Add a Battery Later” — and Why It Usually Costs More
It is one of the most common things solar buyers say in Perth: get the panels now, add the battery when the budget allows. And on the surface, it seems sensible. You are not committing to everything at once.
But here is what that decision actually costs — and why most households that plan to add a battery later end up either paying significantly more when they eventually do, or never getting around to it at all.
This post breaks down the real numbers: what you save by bundling, what you lose by waiting, and the handful of situations where waiting does genuinely make sense.
One Installation Visit Costs Less Than Two
When you get solar installed, there are fixed costs that have nothing to do with the size of the system: getting electricians to site, running conduit, switchboard connections, inspection fees, scaffolding if needed. You are paying for these regardless of what equipment goes in.
If you add a battery later, those fixed costs apply again. A second electrician visit, a second set of switchboard modifications, a second day’s labour. Depending on the complexity of your switchboard and roof access, a standalone battery installation typically adds $500 to $1,500 in additional labour and electrical costs compared to bundling it with the original solar install.
That saving alone often covers the difference in finance costs if you are spreading payments over time.
Get the Inverter Right the First Time
This is where the biggest cost difference lives. When you get solar, you choose an inverter. There are two types:
- Standard (string) inverter: converts solar DC power to AC power for your home. Does not support a battery connection.
- Hybrid inverter: does the same, but also has a battery port. You can connect a battery now or add one later.
The premium for a hybrid inverter over a standard inverter is typically $500 to $1,500. A modest difference when you are already spending $8,000 to $15,000 on a solar system.
But if you choose a standard inverter now and want to add a battery later, you have two options — neither as good as getting a hybrid from the start:
Getting a hybrid inverter from day one is consistently the lowest-cost path to a solar-plus-battery system, especially when you account for the efficiency difference below.
DC vs AC Coupling: The Efficiency Difference
When solar and battery are installed together on a hybrid inverter, they use DC coupling — the battery charges directly from the solar panels without any extra energy conversion step. Energy flows from panels to battery in the same DC format.
When a battery is retrofitted to an existing standard inverter (AC-coupled), there is an extra conversion step: DC from the panels converts to AC, then back to DC to charge the battery, then back to AC for your home. Each conversion loses energy.
In practice, DC-coupled systems are typically 3 to 8 percent more efficient than AC-coupled equivalents. On a 10 kWh battery cycling daily, that is roughly 0.3 to 0.8 kWh of additional usable energy per day from the same solar generation — adding up to over 100 kWh per year. At Synergy’s current rate of 33 cents per kWh, that is $32 to $96 in extra value annually, compounding over the life of the system.
The CHBP Rebate Steps Down Every Six Months — Waiting Costs Money
The federal Cheaper Home Batteries Program (CHBP) provides a point-of-sale discount on eligible battery systems through the Small-scale Technology Certificate (STC) scheme. The rebate is calculated based on the number of STCs assigned to the battery, and that number is tied to the number of years remaining in the scheme — which reduces by one each year.
Practically, this means the rebate is worth more now than it will be in 12 months, and more in 12 months than in 24.
Current indicative CHBP rebate values (mid-2026): approximately $258 per kWh for the first 14 kWh of battery capacity, stepping down to $155 per kWh for 14-28 kWh. These figures change with each deeming period.
A household waiting 18 months to add a 15 kWh battery could be looking at a meaningfully lower point-of-sale discount — potentially $500 to $1,500 less in rebate value depending on where the deeming period lands.
Note: CHBP rebate values are indicative only and change with each STC deeming period. Confirm current figures with Positive Energy Solutions at the time of purchase.
Systems Designed Together Work Better
When your installer sizes a solar-plus-battery system from the start, they can optimise both components for your usage profile. How much solar generation you need to charge the battery daily. Whether a larger solar array makes sense to maximise both self-consumption and battery fill. How your battery size relates to your overnight draw.
Retrofitting a battery to an existing solar system means working around whatever was installed. An array that may have been sized for export rather than self-consumption, an inverter that may not be the most efficient match for the battery chemistry, and a system that was not designed with backup or VPP enrolment in mind.
Every installer Positive Energy Solutions works with sizes solar and battery as an integrated system from the first quote, which means fewer compromises and better long-term performance.
The WA Battery Rebate Is Only Available at Install Time
Western Australia’s Residential Battery Scheme offers an additional $1,300 rebate for eligible batteries through the Synergy Sustainable Living (SSL) program. To access this rebate, the battery must be enrolled in a Virtual Power Plant (VPP) — and that enrolment is set up at the time of installation.
If you get solar now and add a battery later, you can still apply for this rebate at the time of the battery install — but the administrative steps are separate from the solar system, and you need to ensure the battery you choose is on the SSL eligible list. Planning this from the start avoids the risk of choosing a battery that is not VPP-enrolled or SSL-eligible when the time comes.
The full rebate stack available when bundling solar and battery together in Perth:
- CHBP: federal point-of-sale discount through STC scheme (~$258/kWh for first 14 kWh, current mid-2026 rate)
- WA Residential Battery Scheme: $1,300 rebate for SSL-enrolled batteries
- Plenti no-interest loan: up to $10,000 for eligible households (income under $210,000)
“I will Do It Later” Often Becomes Never
This one is not financial — it is behavioural. The reality is that most households who plan to add a battery later take two to four years to actually do it, if they do at all. Life gets in the way. The decision gets re-evaluated. Quotes are sought and shelved. Meanwhile, the rebate has stepped down, the cost of a second installation is sitting there, and the system is exporting cheaply to the grid instead of storing for evening use.
Bundling removes the decision fatigue entirely. The system is designed, quoted, and installed once. The battery starts working from day one.
What a Solar + Battery Package Looks Like With Positive Energy Solutions
Positive Energy Solutions designs solar and battery systems as integrated packages from the first conversation. Every brand we work with — Tesla, Sungrow, SigEnergy, Fronius, and iStore — offers hybrid inverter options, so the system can be sized and optimised as a whole.
At the time of installation, every installer Positive Energy Solutions works with handles the CHBP point-of-sale discount and WA Residential Battery Scheme rebate enrolment as part of the process. Ongoing monitoring, performance tracking, and after-sales support are managed through Omnidian — one point of contact for the life of the system.
If you are at the point of getting solar quotes, it is worth asking the question: what does the system look like with and without a battery? The difference in monthly repayments (if financing) is often smaller than expected, and the long-term picture is substantially better.
Get a Solar + Battery Quote From Positive Energy Solutions
If you are at the solar research stage and want to understand what a fully integrated system looks like for your home, Positive Energy Solutions provides quotes that show you both options — solar only, and solar with battery — so you can make the comparison based on real figures.
Contact Positive Energy Solutions to get a tailored quote for your home.
- What Is the Cheaper Home Batteries Program and How Does It Work in Perth? — /lower-cost-home-batteries-program-perth-2026
- Adding a Battery to Existing Solar in Perth — Is It Worth It? — /adding-battery-to-existing-solar-perth
- Solar Battery Payback Period Perth 2026 — /solar-battery-payback-period-perth-2026
- How to Choose a Solar Battery in Perth — /how-to-choose-solar-battery-perth
- Is a Solar Battery Worth It in Perth? — /is-solar-battery-worth-it-perth-2026
Related guides
- Why Every Positive Energy Solutions System Comes with Omnidian After-Sales Support
- Adding a Battery to Your Existing Solar System in Perth: 2026 Costs, Rebates, and Inverter Compatibility Guide
- Best Solar Batteries for Perth Homes in 2026
- Is LFP Battery Chemistry Right for Perth Homes? A Closer Look at the BYD Battery-Box Premium HVM
Frequently Asked Questions
Can I still add a battery later if I choose a hybrid inverter now?
Yes. A hybrid inverter gives you the option to add a battery at any point in the future. Getting a hybrid inverter now means you avoid the inverter replacement cost when you are ready to add storage. It is the lowest-cost way to stay flexible.
Does the CHBP rebate apply when I bundle solar and battery together?
Yes. The CHBP applies to the battery component regardless of whether you are getting new solar at the same time. The point-of-sale discount comes off the battery price at installation.
What is the difference between a hybrid inverter and a battery-ready inverter?
A hybrid inverter has a built-in battery port and can connect directly to a compatible battery. A ‘battery-ready’ inverter is sometimes used to describe a standard inverter that has been marketed as upgradeable — but in most cases, it still requires an additional inverter component to connect a battery (AC coupling). Always clarify with your installer which type they are quoting.
Is a battery worth it if I am getting solar primarily for daytime usage?
If your home has high daytime electricity use — a home office, pool pump, reverse cycle air conditioning running during the day — solar panels alone may cover most of your consumption. A battery becomes more valuable the more electricity you use in the evenings and overnight. Your installer can model both scenarios based on your actual usage data.
How long does a combined solar and battery installation take?
A combined installation typically takes one to two days depending on the size of the system and switchboard complexity. Adding a battery to an existing solar system later is typically a half to full day — but requires scheduling a separate visit, additional switchboard work, and in some cases, re-inspection.
Which battery brands does Positive Energy Solutions offer?
Positive Energy Solutions works with Tesla Powerwall 3, Sungrow SBR/SBH, SigEnergy, Fronius, and iStore. All are available as part of an integrated solar-plus-battery package. Each has different strengths in terms of capacity, backup capability, and monitoring — your consultant can help match the right system to your home and usage.
About the Author
Jason Wiktorowicz
Sales Manager, Positive Energy Solutions | Perth, WA
Jason has been at the centre of Western Australia’s energy transition for over a decade. As Orchestration Lead on Project Symphony — WA’s largest virtual power plant pilot — and Stream Lead on Project Encore, he worked directly with AEMO, Western Power and Energy Policy WA to shape how distributed energy resources connect and operate on the SWIS. That work included developing and rolling out CSIP-AUS, now mandatory for all new WA grid connections. He also led Emergency Solar Management (ESM), the first program of its kind in WA, VPP for Schools (VPP4S), which provided direct market benefits through Supplementary Reserve Capacity, and REBAR, the WA Residential Battery Rebate scheme.
His earlier career spanned Synergy, Infinite Energy and Curtin University’s Sustainability Policy Institute, where he co-authored peer-reviewed research on net-zero urban precincts, solar integration and peer-to-peer energy trading, published in the journal Urban Planning in 2018.
At Positive Energy Solutions, Jason leads sales with a focus on system design accuracy and long-term performance. Positive Energy Solutions installs solar and battery systems, EV chargers and heat pumps, and holds partner accreditations with Fronius, SigEnergy, iStore and SunPower. Connect with him on LinkedIn.
