Home batteries have become significantly more affordable. That’s good news for homeowners. But it has also created an enormous range of products at very different price points.
At one end of the market are established manufacturers with significant investment in battery technology, software, safety systems, warranties and technical support.
At the other end are products competing heavily on price. This raises an obvious question:
If two batteries both store electricity, why pay more for one than another?
The answer is that battery capacity is only one part of what you’re buying.
A battery isn't just a box full of kilowatt-hours
Battery advertising understandably focuses heavily on capacity.
- 10 kWh.
- 20 kWh.
- 30 kWh.
But knowing the number of kilowatt-hours doesn’t tell you everything you need to know about a battery.
Two 20 kWh battery systems may differ considerably in:
- battery chemistry and cell quality;
- charge and discharge power;
- thermal management;
- battery management systems;
- usable versus nominal capacity;
- software;
- monitoring;
- backup functionality;
- expandability;
- warranty conditions;
- manufacturer support; and
- long-term product availability.
So comparing batteries purely on dollars per kWh can be misleading.
Your battery will work hard
Unlike many products in your home, a battery is actively charging and discharging day after day.
It may spend years responding automatically to changing solar generation, household loads, electricity tariffs and grid conditions.
Over its life it can process a very large amount of energy.
That is why battery cell quality, thermal control and the battery management system matter.
The battery management system continually manages factors such as charge levels, temperature and cell behaviour.
Much of what separates a well-engineered battery from a basic one is technology the homeowner never actually sees.
Software matters more than many people realise
A modern battery is partly an electrical product and partly a technology product.
Good energy-management software determines when the battery charges, when it discharges and how effectively it interacts with solar and the grid.
The app is also the homeowner’s window into the system.
Good software can allow you to easily understand:
- solar generation;
- household electricity consumption;
- battery state of charge;
- grid imports and exports;
- backup reserve;
- historical performance; and
- different battery operating modes.
Manufacturers such as Tesla, Sigenergy, Fronius and Sungrow have developed complete monitoring and energy-management ecosystems around their equipment.
That ongoing software development has value.
The warranty is only as useful as the company behind it
A 10-year warranty printed on a brochure sounds reassuring.
But there are two separate questions to ask:
What does the warranty actually cover?
And:
Who will support that warranty if something goes wrong?
Battery warranties commonly contain conditions relating to remaining capacity, energy throughput, operating environment and correct installation.
The strength and Australian support capability of the manufacturer therefore matter.
So does the installer. If a battery develops a fault several years after installation, the homeowner shouldn’t have to become the project manager between the equipment manufacturer, distributor and electrician.
A good installer can diagnose the problem, communicate with the manufacturer and manage the next steps.
Consider the whole life of the investment
A battery is usually purchased with a long-term objective.
It may be installed on your home for a decade or considerably longer.
Saving money upfront is obviously worthwhile if you’re comparing genuinely equivalent products.
But saving money by choosing a product that proves unreliable, is poorly supported or becomes difficult to service can be a false economy.
The relevant question isn’t simply:
“Which battery costs less today?”
It is:
“Which system is likely to give me the best combination of performance, reliability and support over the years I expect to own it?”
Does that mean the most expensive battery is always best?
No.
Price alone is not an indication of quality.
And paying for functions you don’t need doesn’t make financial sense either.
A homeowner who needs a relatively straightforward 15 kWh storage system may not need every advanced feature available in the market.
Good design is about choosing the appropriate level of technology as well as the appropriate capacity.
The objective should be value, not simply the highest price or the lowest price.
Why AG Solar keeps its battery range focused
There are many battery brands available in Australia.
AG Solar doesn’t try to sell all of them.
We primarily work with Tesla, Sigenergy, Fronius and Sungrow.
That allows our sales, installation and service teams to develop deeper familiarity with the products we install.
It also reflects the type of customer we generally work with.
Our customers tend to be looking for a system they can rely on for many years, rather than simply searching for the lowest possible upfront price.
We would rather recommend a smaller range of products we are comfortable designing, installing and supporting than continually introduce new battery brands simply because they are cheaper.
Buy the outcome, not just the battery
Ultimately, you’re not really buying 20 kWh of battery capacity.
You’re buying the ability to:
- store your solar energy;
- purchase less expensive grid electricity;
- reduce exposure to higher electricity rates;
- gain greater energy independence;
- potentially maintain power during outages; and
- manage your home’s changing electricity requirements for many years.
The battery is simply the technology that enables those outcomes.
If you’re considering home battery storage, compare price – but don’t stop there.
- Compare the product.
- Compare the manufacturer.
- Compare the installer.
- Compare the warranty.
- And compare the support you’ll receive after installation.
At AG Solar, we’ll help you understand those differences and recommend a system based on what you’re trying to achieve – not simply whichever battery happens to have the lowest price this month.
