What are the signs of a failing home battery?

A home battery is a significant investment in your energy independence, so it’s understandable to be concerned if you think it isn’t performing as it should. Like all technology, batteries degrade over time, but sometimes issues can arise that signal a premature failure.

Recognising the signs early can help you address the problem efficiently, ensure your system’s safety, and get the most out of your warranty. The symptoms of a failing battery can range from subtle performance dips to more obvious physical warnings. This guide will walk you through the key indicators to watch out for.

Is your battery’s performance dropping faster than expected?

One of the first signs of a problem is a noticeable decline in your battery’s performance. While all batteries lose some capacity over their lifespan—a process known as battery degradation—a sudden or rapid drop is a red flag.

A common symptom is that your battery no longer lasts through the night or for as long as it once did on a full charge. You might notice your home drawing more power from the grid, leading to an unexpected increase in your electricity bills. This indicates the battery isn’t holding as much energy as it should. Similarly, if it seems to be taking much longer than usual to reach a full charge, this can also signal that the battery is struggling.

Modern lithium-ion batteries are typically warranted for around 10 to 15 years, so a significant performance drop well before this period is cause for investigation.

Are you noticing shorter charge and discharge cycles?

A healthy battery should charge and discharge in a predictable way based on your solar generation and home energy use. If you notice that your battery is charging to full capacity or discharging to empty much quicker than normal, it could indicate failing internal cells.

This rapid cycling means the battery can’t efficiently store and release energy, reducing its overall effectiveness and the savings you expect.

Have you checked your monitoring system for alerts?

Your home battery system includes sophisticated monitoring software, usually accessible via a smartphone app or web portal. This is one of your most powerful tools for spotting issues. Most systems will display error codes or warnings when a fault is detected.

These alerts can be quite specific. For instance, systems from reputable brands like Sungrow or Sigenergy have advanced apps that will often display clear fault codes or plain English warnings like ‘Battery Module Fault’ or ‘Cell Imbalance Detected’. This gives you and your technician a clear starting point for diagnosis. Don’t ignore these notifications; they are the battery’s way of telling you something is wrong.

What are the physical signs of battery failure?

Physical signs of failure are less common but are the most urgent and require immediate attention. If you notice any of the following, you should treat it as a serious safety concern:

Swelling or Bulging: Any visible distortion, swelling, or bulging of the battery casing is a critical warning sign that internal cells may have failed, leading to gas buildup.

Unusual Noises: Hissing, popping, buzzing, or crackling sounds from the battery unit are not normal and can indicate electrical faults or internal damage.

Leaks or Odours: Any fluid leaking from the unit or a strong, unusual chemical smell is a sign of a serious internal breach.

These physical symptoms can point to a risk of thermal runaway, a dangerous chain reaction where the battery overheats. If you observe any of these signs, you should follow your system’s emergency shutdown procedure immediately and contact your installer from a safe distance.

Why has my battery just shut down completely?

A complete and unexpected shutdown of your battery system is another clear indicator of a problem. This is often a safety feature. The battery’s internal management system (BMS) is designed to shut the unit down if it detects a serious fault that could compromise safety, such as extreme temperatures or a critical cell imbalance.

While this protective shutdown is a good thing, it points to an underlying failure that needs to be diagnosed by a professional.

What should you do if you suspect your battery is failing?

If you believe your battery is failing, it’s important to act methodically and prioritise safety.

First, if you notice any physical signs of damage like swelling, strange noises, or leaks, activate the system’s shutdown procedure as outlined by your installer and contact them immediately. Do not attempt to fix or touch the battery.

For performance-related issues, the first step is to document everything. Take screenshots of any error codes on your monitoring app, make notes of your observations (e.g., “battery only lasts until 2 am now”), and have your installation paperwork handy.

Next, contact the SAA-accredited installer who originally installed your system. They are your first point of call and are responsible for diagnosing the issue, liaising with the manufacturer, and managing any warranty claims. Under Australian Consumer Law, your installer and the product manufacturer are responsible for ensuring the product is of acceptable quality.

Conclusion

Being aware of your home battery’s day-to-day performance is the key to spotting potential problems early. Regularly checking your monitoring app and keeping an eye on how long your battery is lasting will help you identify any unwelcome changes. While performance dips and error codes are the most common signs, always treat physical changes like swelling or noises with the utmost seriousness.

A failing battery can be worrying, but by acting promptly and contacting your installer, you can ensure the issue is resolved safely and professionally. If your original installer is no longer available, Your Energy Answers can help you connect with a trusted, accredited local expert to provide the support you need.