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4 Critical Signs Your Car Battery Is Failing – Don’t Get Stranded!

  • Writer: BMTech
    BMTech
  • Mar 24
  • 4 min read

BMW engine with battery mount and terminals | BM Tech Melbourne
BMW Battery Testing | BM Tech

A car's battery is indispensable, powering not only the ignition system but also the myriad of electronic components that modern vehicles rely upon. Despite its crucial role, the battery often remains overlooked - that is until a malfunction occurs! Recognising the early signs of a failing battery can prevent inconvenient breakdowns and costly repairs. This comprehensive guide delves into the indicators of a deteriorating car battery, the importance of regular maintenance, and best practices to extend its lifespan.​

Understanding the Role of the Car Battery

The primary function of a car battery is to supply the necessary electrical current to start the engine. Beyond ignition, it stabilises voltage to keep the engine running and powers essential accessories such as lights, radios, and onboard computers. Given its central role, any decline in battery performance can significantly impact vehicle operation.​

Key Indicators of a Failing Car Battery

  • Illuminated Battery Warning Light: Modern vehicles are equipped with dashboard warning systems to alert drivers of potential issues. An illuminated battery warning light indicates that the battery isn't charging correctly. This could stem from problems within the battery itself or related components like the alternator or voltage regulator. Immediate attention from a qualified technician is advisable to diagnose and rectify the issue.​

  • Slow Engine Crank: A healthy battery provides a swift, robust crank to start the engine. If you notice the engine turning over sluggishly or taking longer than usual to start, it may be a sign that the battery's charge is diminishing. This symptom often precedes complete battery failure.​

  • Clicking Sound Upon Ignition: Hearing a clicking noise when turning the key or pressing the start button typically indicates insufficient power to engage the starter motor. This is often due to a weakened or discharged battery. In such cases, the battery may require charging or replacement.​

  • Dim Headlights and Electrical Issues: The battery powers all of the vehicle's electrical components. Dimming headlights, malfunctioning power windows, or unresponsive infotainment systems can signal a declining battery. These issues arise because the battery can no longer supply adequate power to all systems.​

  • Corroded Battery Terminals: Corrosion appears as a white, ashy substance on the battery terminals and can impede the connection between the battery and the vehicle's electrical system. Regular inspection and cleaning of the terminals can prevent starting issues and prolong battery life. For guidance on proper cleaning techniques, refer to Marshall Batteries' maintenance tips.

    Marshall Batteries

    ​Swollen or Bloated Battery Case: Exposure to excessive heat can cause the battery case to swell, reducing its lifespan. A bloated battery is a clear indication that it's no longer functioning properly and requires immediate replacement.​

  • Unpleasant Odour: A failing battery may emit a smell similar to rotten eggs, indicating a leak of sulfuric acid. This not only damages the battery but can also harm other engine components. If such an odour is detected, it's crucial to have the battery inspected promptly.​

  • Advanced Age: Car batteries typically last between three to five years. Factors such as driving habits, climate, and maintenance practices can influence this lifespan. If your battery is approaching or has surpassed this age range, proactive testing and potential replacement are wise measures. ​

Best Practices for Car Battery Maintenance

  • Regular Inspection and Cleaning: Periodically check the battery terminals for signs of corrosion. Cleaning the terminals with a mixture of baking soda and water can prevent build up and ensure a solid connection. Always ensure the engine is off and wear protective gear during this process. ​

  • Secure the Battery: A loosely mounted battery can vibrate, leading to internal damage and reduced lifespan. Ensure the battery is securely fastened to minimise movement.​

  • Limit Short Trips: Frequent short drives prevent the battery from fully charging, leading to a shortened lifespan. Combining errands or taking longer drives periodically can help maintain the battery's charge. ​

  • Turn Off Accessories When Idling: Using electronic features like the radio or air conditioning while the engine is off drains the battery. To conserve battery life, ensure all accessories are turned off when the vehicle isn't running.​

  • Protect Against Extreme Temperatures: Both excessive heat and cold can adversely affect battery performance. Parking in shaded areas during summer and in garages during winter can help mitigate temperature-related damage. ​

  • Regular Charging: If a vehicle is infrequently used, the battery can gradually lose its charge. Utilising a battery maintainer or trickle charger can keep the battery at optimal charge levels during periods of inactivity. ​

  • Monitor Electrolyte Levels: For batteries that aren't sealed, it's essential to check the electrolyte levels regularly. If low, top up with distilled water, ensuring not to overfill. Always follow the manufacturer's guidelines when performing this task. ​


When to Seek Professional Assistance

While regular maintenance can significantly extend battery life, professional evaluation is indispensable, especially when issues arise. Certified technicians possess the tools and expertise to conduct comprehensive battery tests, identifying problems that may not be apparent during routine inspections. Routine check-ups can preempt unexpected failures and ensure the vehicle's electrical system operates seamlessly.​

Environmental Considerations

Proper disposal of old car batteries is crucial, as they contain hazardous materials that can harm


Book Your Car Battery Check with BM Tech

A well-maintained car battery is fundamental to the reliable operation of your vehicle. By staying vigilant for signs of battery failure and following best practices for maintenance, you can extend the lifespan of your battery and avoid unexpected breakdowns.

If you're unsure about the condition of your car battery or need a replacement, BM Tech offers professional battery testing, maintenance, and replacement services in Melbourne's Canterbury, Victoria. Their expert technicians can ensure your vehicle remains in top condition with a thorough inspection and the right battery for your car.


Book your battery check with BM Tech today and drive with confidence. Visit BM Tech’s website or call their team to schedule an appointment.

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