If your solar panels are sending most of their power back to the grid during the day while you pay full price for electricity at night, a battery is usually the next step. Adding batteries for solar systems lets you store what your panels make and use it after sunset, during peak times or when the power goes out.
Not every battery suits every home. The right choice depends on how you use power, your existing inverter and whether you want backup. Here is how our electricians approach it.
Choosing a Solar Battery?
Gel, lithium-ion, saltwater or lead-acid – each suits a different home. Get expert guidance from Charlie Sparks.
Key Takeaways
- A solar battery stores daytime solar so you can use it at night instead of buying from the grid.
- Size the battery to your evening and overnight usage, not to the size of your solar system.
- Your existing inverter decides whether you add an AC-coupled battery or switch to a hybrid inverter.
- Backup during blackouts is not automatic. It has to be designed and wired in.
How a Battery Works With Your Solar System
During the day, your panels power the house first. Any extra energy charges the battery instead of going straight to the grid. Once the sun drops, the battery takes over and runs your lights, fridge, TV and cooking. When the battery is empty, the house draws from the grid as normal. You use more of your own solar and buy less power at the most expensive times of day.
AC-Coupled or DC-Coupled: What Your Inverter Means
This is one of the first things we check on a site visit, because it shapes the whole job.
Adding a Battery to Existing Solar
If you already have solar with a standard inverter, an AC-coupled battery is often the easiest path. It comes with its own built-in inverter and connects to your switchboard, so your current panels and inverter stay in place.
Installing Solar and a Battery Together
If you are installing new solar, or your old inverter is due for replacement, a hybrid inverter can manage both the panels and the battery in one unit. This DC-coupled setup is efficient and keeps the equipment on your wall neat.
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An older inverter that still works well might be worth keeping, while one near the end of its life is a good reason to go hybrid.
Sizing Your Battery the Right Way
A common mistake is choosing a battery based on the size of the solar system. What matters more is how much power you use after the sun goes down.
When we size a battery, we look at:
- Your electricity bills or smart meter data to see evening and overnight usage
- How much excess solar you export on a typical day
- Whether you work from home, run a pool pump or have ducted air con
- Plans for an electric car, an induction cooktop or a heat pump hot water system
- Whether you want enough stored power to cover a blackout
A battery that is too small runs flat early in the evening. One that is too big may never fill up from your panels, especially in winter. That is why our solar battery storage service starts with your real usage data rather than a standard package.
Blackout Backup: Plan It From the Start
Many people assume a battery will keep the lights on during a power cut. Without the right setup, it will not. Most grid-connected systems shut down when the grid goes down, for the safety of line workers.
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To get backup, the system needs a backup-capable battery or inverter and dedicated backup circuits in your switchboard. Most homes choose to back up the essentials, such as the fridge, lights, internet and a few power points. Deciding this before install day saves you paying for changes later.
What to Compare Between Batteries
Once the size and setup are clear, these are the details worth comparing:
Usable Capacity
Look at usable capacity, not just the total figure on the box. Usable capacity is what you can actually draw from the battery each day.
Power Output
This is how much the battery can deliver at once. A low output can struggle when the oven, kettle and air con run together, even if the battery still has plenty of charge.
Battery Chemistry
Most home batteries installed today use lithium iron phosphate (LFP). It is stable, handles daily cycling well and suits Australian heat better than older chemistries. Lead-acid batteries are mostly limited to off-grid and budget setups now.
Warranty Terms
Check the warranty period and the guaranteed capacity at the end of it. Some warranties also limit how much energy can pass through the battery over its life.
Brand Support in Australia
Brands with local support, such as Tesla Powerwall, Sungrow and GoodWe, make warranty claims and future service much easier.
Where the Battery Goes
Batteries need a spot that is protected from direct sun, flooding and impact, with enough clearance for airflow and safe access. Garages and shaded external walls are common choices. Australian standards also limit placement near bedrooms, exits and certain parts of the home, which is something your installer should check on site.
Why Your Installer Matters
A solar battery holds a lot of energy, so the install matters as much as the product. Use an installer with Clean Energy Council battery accreditation who handles the design, switchboard work, grid approval and rebate paperwork, then sets up your monitoring app.
Ready to Add Battery Storage?
Book a licensed Sydney team to recommend and install the right solar battery for you. Talk to Charlie Sparks.
Frequently Asked Questions
Can I add a battery to my existing solar system?
Yes, in most cases. An AC-coupled battery can connect to an existing system, or your inverter can be replaced with a hybrid unit if it is due for an upgrade.
Will a solar battery work during a blackout?
Only if the system is designed for backup. You need a backup-capable battery or inverter and backup circuits wired into your switchboard.
How long do home solar batteries last?
Most quality lithium batteries carry warranties of around 10 years. Real lifespan depends on daily use and where the battery is installed.
Ready to Add a Battery to Your Solar?
Charlie Sparks designs and installs solar battery systems across Sydney, from retrofits on existing solar to new hybrid setups with blackout backup. Our team sizes your battery from your actual usage, so you are not left short or paying for capacity you will not use. Contact our team or call (02) 8310 4077 to book your battery assessment.