Batteries
How to choose the best solar battery for your Perth home
Usable capacity, efficiency, warranty, compatibility and backup, and which of them actually changes what you get out of a battery.
If you want to get more out of your panels after sunset, the battery decision matters as much as the solar decision did. A battery that suits your house can cut what you buy back from the grid in the evening and keep the essentials running through an outage. A battery that does not suit it sits half used and takes a very long time to pay for itself.
The difference between the two is rarely the brand. It is whether anyone matched the battery to how your household actually uses power.
What actually decides which battery suits you
Start with what you use after dark
The useful question is not how big a battery you can fit. It is how much electricity your house uses once the panels stop generating, and how much surplus solar you have spare to store in the first place.
Those two numbers come off your bills and your inverter's own monitoring, not off a product page. A household where everyone is out until six and then runs the oven, the air conditioning and the hot water has a completely different answer to one that is quiet by eight.
Compare usable capacity rather than the headline figure, because they are not the same number and the gap between them varies by product. And treat any capacity recommendation made before someone has seen your consumption data with suspicion. We size on site, off your own figures, because there is no other honest way to do it.
Efficiency, and what it costs you over time
Every battery loses a little energy on the way in and a little more on the way out. Round trip efficiency is how much of your stored solar you actually get back, and a few percentage points compound across a decade of daily cycling.
Worth asking about alongside it: the degradation rate, the cycle life, and the temperature range the figures were measured at. A Perth garage in February is not a laboratory.
The warranty is the honest part of the spec sheet
A warranty tells you what the manufacturer is prepared to stand behind, which is more useful than what the brochure claims. Read the guaranteed remaining capacity at the end of the term, the throughput or cycle limit, and what actually happens if it underperforms.
Do not compare warranties on years alone. A longer term with a tighter throughput cap can be the shorter warranty in practice, depending on how hard you cycle the battery.
Ask who honours it, too. A warranty is only as good as the company still being there to answer the phone, which applies to the manufacturer and to whoever installed it.
It has to work with the system you already have
If you already have solar, the battery has to work with your inverter, your switchboard, your wiring and the space available. An older inverter may not support the battery you want, which either rules it out or adds an inverter to the job.
Compatibility between battery and inverter brands varies, and the approved product lists change as new equipment is certified. This is the single most common reason a battery quote comes back different to what somebody expected, and it is why the switchboard and the inverter get looked at before a product is recommended rather than after.
Backup is a separate decision, and it has to be made first
A battery does not automatically keep your house running in a blackout. Backup is a different wiring job with different equipment, and retrofitting it afterwards costs more than including it at the start.
So decide early, and decide specifically. Most people want the fridge, the lights, the internet and a few power points. Running the ducted air conditioning through an outage is a much larger ask, and it is limited by the battery's power output rather than its stored energy. A battery can hold plenty of energy and still be unable to start a big load.
Safety, installation and who you ring in year six
Placement, ventilation, electrical protection, isolation and clearances are all governed by the manufacturer's requirements and the wiring rules, and they are the parts of a battery install that nobody looks at once the cover is on.
Ask who is doing the electrical work, whether they are employed by the company quoting it, and who you call when something looks wrong in a few years. We do our own installs for that reason.
The battery that fits your house, not the biggest one on the list
The best battery for your home is the one matched to your solar generation, your evening use, your existing equipment and what you want backed up. That is an assessment, not a product recommendation, and it starts with your bills.
If a smaller system is better, we will tell you. We have told people the answer was to wait, and we would rather do that than sell storage that sits idle.
FAQs
Questions on this
How do solar batteries work?
They store the surplus your panels generate during the day instead of exporting all of it, then supply that stored energy back to the house after the sun goes down, so you buy less from the grid in the evening.
What happens when the battery is full?
Once it reaches usable capacity the system sends any further solar to the grid, subject to your connection agreement and your plan. Your inverter and energy management settings decide the order.
How do I know if I have enough solar to justify a battery?
Look at how much you export during the day against how much you buy back at night. If you are exporting very little, the battery has nothing to store. That is the first thing we check, and it is the reason we occasionally tell people to wait.
Get a quote
Thinking about a battery?
Send your last few power bills. We will tell you what your evening use actually is and whether storage is worth it yet.