This project took place at a residential property in Drewvale, on Brisbane's southern fringe, an area Rethink Green Energy regularly services alongside Ipswich, Logan and the wider south east Queensland region. The homeowner already had a solar system installed at the property. This job added a further 6.6kW of panel capacity and, for the first time at this address, a home battery.
The work was carried out and tested on 17 July 2026 by an accredited installer, with the completed system connected to the grid and confirmed compliant through a formal Certificate of Testing and Compliance. Because no financial or generation data was supplied for this project, this case study focuses on what can be verified: the equipment installed, how it was configured, and the compliance record behind it.
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The homeowner already had solar panels on the roof before this project began, confirmed by the compliance paperwork, which records this job as an additional installation rather than a first-time solar system. What the property did not have was any form of battery storage, meaning any solar power generated beyond what the household used immediately was exported to the grid rather than stored for later.
The roof itself presented a practical planning consideration. Site photographs show the new panels split across two separate roof planes, one facing broadly south west and one facing broadly south, based on the compass overlays recorded at the time of the site visit. Neither orientation is the most efficient direction for solar in the southern hemisphere, which points to the original north facing roof space already being taken up by the existing array.
Simply adding more panels would not have solved the underlying issue on its own. Without storage, the extra solar generated during the day still has nowhere to go once the home's own usage is covered, other than back out to the grid. A battery was the piece needed to let the household use more of its own solar generation later in the day.
Rethink Green Energy's recommendation combined two things: 6.6kW of additional panel capacity, and the property's first battery, a 20kWh usable GoodWe system built from four GW5.1-BAT-D-G20 modules. Both the new panels and the battery were connected through a single new GoodWe GW9.999K-EHA-G20 hybrid inverter from GoodWe's ESA range, which manages solar generation and battery charging and discharging from one unit rather than splitting the job across separate solar and battery inverters.
The panels chosen were Huansheng Photovoltaic HSM-ND48-DR440 modules, rated at 440W each and certified to IEC 61215:2021, the international standard that tests a crystalline silicon panel's design and durability under sustained real world conditions such as temperature cycling, mechanical load and humidity. Fifteen of these panels make up the new 6.6kW of capacity.
A 20kWh usable battery sits toward the larger end of what is typically installed in a home battery retrofit. Sizing a battery correctly depends on how much electricity a household actually uses overnight, which was not detailed in the documents supplied for this project, so this case study does not claim the battery was sized against a specific usage figure for this home. What can be confirmed is that the battery was installed as a complete, VPP-capable system, meaning it is technically ready to take part in a virtual power plant program in future if the homeowner chooses to enrol, without needing further hardware changes.
The new panel capacity was installed across two separate roof faces rather than one continuous array. Photographs from the job show one section facing broadly south west and a second facing broadly south. This is consistent with a property where the best north facing roof space was already committed to the existing solar system, requiring the additional panels to be placed on the next most suitable available sections of roof.
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The documented steps for this job cover site assessment and system design, equipment selection, installation, electrical testing, and formal compliance certification. Site assessment and system design covering panel placement and equipment selection are part of Rethink Green Energy's standard process for every project, rather than steps specifically documented for this job in the supplied paperwork.
The installation itself was carried out on 17 July 2026. Photographs from the job show the switchboard fitted with dedicated PV and energy storage (ES) isolation points, along with the required danger and shutdown procedure signage fitted directly to the battery enclosure, covering battery explosion risk, toxic fumes, and the isolator shutdown sequence for the inverter, PV array and battery.
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Once installed, the system was tested and a Certificate of Testing and Compliance was issued for the same date, confirming the installation meets the requirements of the Electrical Safety Regulation 2013 for both the electrical installation and the electrical equipment involved. The certificate lists the panel, inverter and battery models exactly as installed, along with the property's National Metering Identifier.
The job also generated 164 small-scale technology certificates (STCs) under a 5 year deeming period, assigned to FormBay Trading Pty Ltd as part of the standard rebate process that applies to eligible solar and battery installations in Australia.
A growing number of Queensland homeowners already have solar and are now looking at a battery as the next step, rather than starting from scratch. Rethink Green Energy's own market research notes this shift, driven partly by ongoing interest in federal and state battery incentives and partly by households wanting more control over when they use their own solar power rather than exporting it during the day and buying it back at night.
This project is a useful example of that pattern in practice. It shows Rethink Green Energy working with an existing system rather than a blank roof, fitting new panels around the space already used by the original array, and bringing in a hybrid inverter and battery combination that keeps the switchboard straightforward rather than adding a second, separate battery inverter. The compliance paperwork and site photographs back up that the work was completed to the required electrical safety standard and properly documented, which matters for any homeowner who is trusting a business with an addition to an existing, already-functioning system.
Rethink Green Energy is a family owned and Australian operated solar business servicing homes and businesses across Queensland and New South Wales. Installations are carried out by CEC accredited installers, and every job is backed by a 25 year workmanship warranty. The business also offers $0 upfront options for eligible customers and provides ongoing support beyond the day of installation, including system monitoring, cleaning and repairs.
Rather than selling a bigger system than a property needs, Rethink Green Energy's stated approach is to size each system, including additions like this one, around the property and the equipment already in place. This project reflects that approach: an addition scaled to the available roof space, paired with a battery sized to work with the existing solar array rather than requiring it to be replaced.
If you already have solar and are weighing up whether a battery, or extra panels, makes sense for your home, Rethink Green Energy offers a free, no obligation assessment to look at your existing system and talk through the options. Get in touch to arrange a time for a local, CEC accredited installer to take a look.
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