The short version

Key points

  • Growatt systems are described as an affordable mid-tier option, with around 90% of Sunterra’s installations using the brand.
  • Battery sizing should be based on average daily electricity imports and expected night-time usage.
  • The installer says typical payback is around six years, with three to five years possible in favourable circumstances.
  • In Western Australia, battery rebate recipients need a continuously connected Wi-Fi connection for grid-management purposes.
  • The discussion indicates that the Synergy virtual power plant arrangement may continue beyond its initial two-year rates period, although future rates and conditions may change.

Where Growatt sits in the market

Dean, who says he has worked in solar for about four years, explains that Sunterra mainly installs Growatt inverters and batteries. He estimates that Growatt accounts for approximately 90% of the company’s installations because of its perceived combination of reliability and affordability.

He places Growatt in the mid-tier or “affordable premium” segment, alongside brands such as SolaX and GoodWe. It is not positioned as a top-tier premium product, which may be more expensive and may not always deliver the best payback for a customer’s circumstances.

Why households add a battery

The main use case discussed is storing excess daytime solar for use after people return home. Households that work during the day may generate solar power while they are away, then use the stored energy for cooking, lighting, television and other evening loads.

Customers can add a battery to an existing solar installation or purchase a combined solar and battery system. Dean says systems should be designed around the customer’s electricity bill rather than simply choosing the largest available system.

Sizing the inverter and battery

For a starting point, Dean recommends checking average daily electricity imports. In Western Australia, he says this figure appears on the front page of a Synergy bill. Daily usage varies, so the figure is intended as a guide rather than an exact daily requirement.

As an example, he associates imports of about 25 kilowatt-hours per day with an inverter of roughly 5 kilowatts, while usage around 40 to 50 kilowatt-hours per day may require something closer to a 10-kilowatt inverter. For battery capacity, he suggests using roughly 30% to 40% of average daily usage as an indication of typical overnight consumption. These figures are not presented as a substitute for a tailored system design.

How the system operates

The system prioritises household demand from the solar panels. Once the home’s demand is met, excess generation charges the battery. When the battery is full and household demand is covered, remaining eligible generation can be exported to the grid.

The discussion notes that export limits can restrict how much energy is sent to the grid. In the example system, the export limit is described as approximately 1.5 kilowatts. Generation that cannot be used, stored or exported is not held as a dangerous build-up of energy; the system simply sends through what can be accepted at the time.

Safety, maintenance and warranties

Dean stresses the importance of using a properly accredited battery installer and following installation regulations. He says batteries include layers of arc-flash protection, but also warns customers to check the installer’s credentials and history rather than relying only on the product name.

Routine maintenance is described as limited. Owners can check the inverter’s indicator light and use the associated mobile app to monitor solar production and whether the battery is charging. Warranty claims for the product or installation are handled through Sunterra, which liaises with the relevant manufacturer where required. Internet connectivity may also be needed for system communications and Western Australian grid-management requirements.

TechManPat’s conclusion

My view is that the installer matters just as much as the battery brand. The most useful advice from this discussion is to size the system around your actual usage, check the company’s accreditation and track record, and understand the rebate and virtual power plant conditions before committing. The VPP details, including future rates and export behaviour, still need to be confirmed as the program rolls out.
Source note

This knowledge-centre summary is based on the linked TechManPat video and reflects the information available when it was published. Check current pricing, availability and policies before acting.