Why Your Car Battery Keeps Dying and How to Fix It

Is your car’s battery always running flat? If so, you’re not alone. A survey by Budget Direct Insurance found that battery-related issues made up 43% of all roadside assistance callouts in Australia in 2022. While roadside assistance is often a convenient solution, many battery issues can be handled yourself with just a bit of know-how. Here’s a breakdown of why your car battery might be dying and how to fix it.

How Your Battery Recharges While Driving

Your car’s battery has a simple job: powering the electronics when the engine is off and providing the spark to start your car. While driving, an alternator—connected to your engine by a belt—keeps the battery charged and powers other electrical systems. If your alternator is working properly, it should keep your battery fully charged as you drive.

Common Reasons for a Failing Car Battery

If your car battery is constantly dying, here are the key areas to check before calling roadside assistance:

1. Check the Battery Terminals

Over time, the terminals on your battery may loosen or develop corrosion. Loose terminals can disrupt the connection and prevent the battery from charging properly. Here’s what to do:

• Inspect and Tighten: Try to move the battery leads; they should be snug and not easily shifted.
• Check for Corrosion: Corroded terminals often develop a blue, mold-like residue. Wearing gloves, you can clean the terminals with a wire brush or a battery terminal cleaner to remove the buildup and prevent further corrosion.

2. Consider Replacing the Battery

Car batteries typically last between three and six years, but they lose capacity over time due to temperature and charge cycles. Older batteries may hold only a limited charge, making it harder to start your car. Here’s how to assess your battery’s health:

• Magic Eye Indicator: Many batteries have a small indicator on top. A green indicator means the battery is sufficiently charged, while a red indicator signals it may need recharging or replacing.
• Top-Up Distilled Water: If low water levels are causing the issue, some batteries can be topped off with distilled water. However, if your battery is consistently drained, it’s likely time for a new one.

3. Inspect the Alternator

A failing alternator won’t just fail to charge your battery; it can actively drain it while you drive, leaving your car without power. To test your alternator:

• Remove the Negative Terminal: On older vehicles, start the car and disconnect the negative battery terminal. If the engine stops, the alternator is likely faulty.
• Use a Voltage Meter: Attach a voltage meter to your battery while the car is running. A reading below 12 volts at idle indicates the alternator may need replacement.

4. Faulty Light Switches

Sometimes, the culprit is a simple switch. Small lights—like those in your glovebox or brake lights—can drain your battery if their switches are faulty:

• Glovebox Light: If the glovebox switch is damaged, the light may stay on even when the glovebox is closed, draining your battery when the car is off.
• Brake Light Switch: When the brake pedal is pressed, a switch activates the brake lights. A malfunctioning switch can leave the lights on constantly. Do a quick check outside your car to ensure your brake lights turn off when the pedal is released.

Final Thoughts

A car battery that constantly dies can be a frustrating issue, but the good news is that many causes are simple to fix. By checking your battery terminals, testing the alternator, and ensuring all lights are off, you can potentially avoid frequent jump-starts and extend the life of your battery. If problems persist, a mechanic can help identify the root cause and get your car back to reliable starting.