Are Cheap Batteries Cutting Corners? What We’re Seeing This Winter

The battery market in Australia has changed rapidly over the last few years. Systems are getting bigger, prices are getting cheaper, and more homeowners than ever are looking at battery storage to reduce power bills and improve energy independence.

But as the race to the bottom on pricing continues, one thing is becoming very clear — not all battery systems are designed for real Australian conditions.

Over the past few weeks, we’ve started hearing more reports of battery systems heavily reducing their charge and discharge rates during cold mornings. In some cases, systems designed to charge quickly are slowing down dramatically once temperatures drop.

This is not necessarily a “fault.” Lithium batteries naturally become less efficient in colder temperatures. The issue is how manufacturers choose to manage that problem.

Premium battery manufacturers generally engineer systems with proper thermal management, heating functions, and long-term performance considerations built in. Lower-cost systems often reduce costs by simplifying or removing some of these features altogether.

The challenge is that many customers are now installing significantly larger battery systems than ever before. Years ago, a small battery may have only needed to slowly top up throughout the day. Now we are regularly seeing 30kWh, 40kWh and even larger systems designed around off-peak charging windows, free energy periods, EV charging, and full-home backup.

When a large battery cannot charge efficiently during winter conditions, the entire design strategy of the system can be affected.

This is particularly important in regional NSW, where winter heating demand can often exceed summer cooling demand. If a battery system struggles during cold mornings or cannot fully utilise cheaper charging windows, the financial return can quickly change.

What concerns us most is not even the reduced performance itself — it is the DIY solutions some homeowners attempt afterwards.

We are already seeing people insulating batteries themselves, enclosing systems, or modifying installations trying to “help” performance in colder weather. Battery systems generate heat and require proper airflow, clearances, and manufacturer-approved installation methods. Modifying these conditions can create serious safety risks.

This is where experience, system design, and proper product selection matter.

At Zac Power we are very selective about the products we install. Not because we want to sell the cheapest system possible, but because we want systems to still perform properly years later in real Australian conditions.

A battery system is not just about the upfront price per kilowatt-hour anymore. It is about:

• Long-term reliability
• Thermal management
• Local support
• Warranty backing
• Real-world performance
• Expandability
• Safety
• Backup capability
• Software maturity
• Manufacturer support

The reality is that Australia’s rebate-driven market is putting enormous pressure on manufacturers to hit aggressive pricing targets. Some brands will handle that pressure better than others.

As installers, we believe the industry needs to stop focusing purely on “cheapest price” and start focusing again on proper system engineering and long-term performance.

Because a battery that looks great on paper means very little if it cannot consistently perform when your home actually needs it most — whether that is during a summer heatwave or a freezing winter morning.