If you already have a 6.6–20 kW solar system at your Adelaide home, adding a battery can help you make better use of the energy your panels produce during the day.
But a bigger solar system doesn’t automatically mean you need the biggest battery. The right size depends on how much excess solar you generate and when your household uses electricity.
Start with your solar and energy usage
A 6.6 kW system and a 20 kW system can have very different energy production and household requirements.
If your home is empty during much of the day and most of your electricity use happens in the evening, a battery can store some of your excess daytime solar for later.
If you’re already using a lot of your solar during the day, a smaller battery may be enough.
What battery size should you consider?
For homes with 6.6–20 kW solar systems, battery sizes can vary considerably. A common starting point may be around 10–30 kWh of usable storage, but the right capacity needs to be calculated from your actual energy consumption and solar exports.
For example:
- 6.6 kW solar: A smaller battery may be suitable for moderate household usage.
- 10–15 kW solar: A medium-to-larger battery can make sense where there is significant excess solar.
- 15–20 kW solar: Larger storage may be worth considering, particularly for homes with higher evening consumption.
These are only starting points. Battery sizing should be based on your actual usage and solar generation, not just your panel capacity.
Look beyond the kWh number
When comparing batteries, check more than storage capacity.
Consider:
- Usable capacity – how much energy you can actually use
- Power output – how much electricity the battery can supply at once
- Warranty – including cycle or throughput conditions
- Battery chemistry and safety features
- Inverter compatibility
- Backup capability, if you want power during an outage
- Manufacturer and installer support
It’s also worth checking whether the specific battery model is on the Clean Energy Council approved products listwhere applicable. (cleanenergycouncil.org.au)
Don’t oversize your battery
It can be tempting to think that more storage is always better.
It isn’t.
If your battery is much larger than the amount of excess solar your home can regularly store and use, part of that capacity may not be used often enough to justify the additional cost.
A properly sized battery should work with your solar production, household consumption and electricity tariff.
What about backup power?
If you’re considering a battery partly for Adelaide power outages, ask about backup from the beginning.
A battery does not automatically keep your home running during a blackout. Backup requires the appropriate system configuration and electrical setup. Depending on the system, it may supply selected essential circuits or a larger portion of the home.
Get the system assessed properly
Before choosing a battery, have an installer review your electricity bills, solar production and existing inverter.
For a 6.6–20 kW solar system, the best battery could be very different from one household to another.
The goal isn’t to install the biggest battery possible. It’s to install the right-sized battery for the way your home actually uses energy.
Ready to Choose the Right Solar Battery?
The best way to choose the right solar battery is to start with your real energy usage, not the biggest kWh number on a brochure. Use our solar battery calculator to estimate your savings, rebate and a sensible battery size for your Adelaide home in under a minute. If you already have panels on the roof, find out whether you can add a battery to an existing solar system before you think about replacing anything. A correctly sized battery stores the solar you would otherwise export cheaply and powers your home through the expensive evening peak. Get the numbers first, then invest with confidence.
