Busted! 6 Car Battery Myths Every Driver Should Know – With Help from Tynan Motors

Car batteries are one of the most misunderstood components under the bonnet. At Tynan Motors, we regularly speak to drivers unsure about battery care, lifespan, and what to do when their car won’t start. So, we’ve put together this myth-busting guide to separate fact from fiction—and help you avoid being left stranded.

1. A Car Battery Has a Defined Lifespan – False

Many believe their car battery is guaranteed to last a set number of years. In truth, a battery’s lifespan is influenced by driving habits, vehicle type, climate, and maintenance—not just the manufacturer’s warranty.

Factors that can shorten battery life include:

• Leaving accessories like the stereo or air con running while the engine is off
• Letting the car sit unused for extended periods
• Constantly taking short trips (we’ll explain more below)

On the flip side, well-maintained batteries can last beyond their warranty. Some early Toyota Camry Hybrids—often used as taxis—have been known to operate for years after their battery warranties expired.

At Tynan Motors, our technicians can assess battery health and advise whether replacement or maintenance is needed.

2. All Car Batteries Are the Same – False

This is a common misconception. As cars have become more complex, so have their power demands. Vehicles with stop/start technology, for instance, require AGM (Absorbent Glass Mat) batteries, unlike the standard calcium ones found in traditional cars.

Another important metric to consider is the Cold Cranking Amps (CCA) rating:

• The CCA rating tells you how well the battery will perform in cold weather
• The higher the CCA, the better—especially for those living in cooler climates

In Australia’s warmer weather, the Reserve Capacity (RC) is a more relevant spec. Again, higher numbers usually indicate better quality and longer performance.

Looking for a battery replacement? Our expert team at Tynan Motors can help you choose the right one for your vehicle.

3. Your Battery Can Go Flat If Your Keys Are Too Close to the Car – True

Yes, this one’s surprisingly true—and often overlooked. Many modern vehicles have proximity key fobs, which constantly communicate with the car when nearby.

If your key is left close to the vehicle (like on a hook in the garage or inside the cabin), the car can enter a state of “readiness”, slowly draining the battery over time. To prevent this, store your keys away from the vehicle when not in use—especially if your car sits idle.

4. Driving Will Fully Recharge a Flat Battery – False

Driving helps maintain your battery’s charge—not fully restore it. If the battery is deeply discharged or flat, a 30-minute drive won’t cut it. Worse still, relying on the alternator to recharge a dead battery can overwork your charging system, leading to more issues.

Instead, use a dedicated DC battery charger, or if the battery is old, consider replacing it altogether. For infrequently used vehicles like classics or campervans, a trickle charger is ideal to keep the battery topped up.

Need battery advice? Drop into Tynan Motors for a check-up and expert guidance.

5. Maintenance-Free Batteries Don’t Need Checking – False

“Maintenance-free” doesn’t mean “ignore it completely.” These batteries don’t need topping up with water, but you should still:

• Inspect the terminals for corrosion or grime
• Keep the battery clean and securely mounted
• Check voltage regularly

Simple maintenance can extend your battery’s life and keep your vehicle running reliably. At Tynan Motors, our service technicians include this check in routine servicing.

6. Driving Only Short Trips Can Drain Your Battery – True

If most of your drives are under 20 minutes, your battery doesn’t have enough time to recharge after the initial drain caused by starting the engine.

Over time, this results in a slow depletion of charge, eventually leading to a flat battery. If short trips are unavoidable, consider:

• Combining errands into a longer journey
• Occasionally taking the car for a longer drive
• Charging the battery at home with a suitable charger

Bonus Tip: NRMA Battery Support

Did you know the NRMA offers 24/7 battery replacement? Members receive $60 off the cost and installation, and the technician will even recycle your old battery.

While Tynan Motors can assist with in-house replacements, it’s handy to know roadside support is just a call away when you're in a pinch.

Power Up with Confidence at Tynan Motors

Understanding how your car battery works—and how to care for it—can save you time, money, and stress. Whether you need a battery test, replacement, or advice, the friendly and knowledgeable team at Tynan Motors is here to help.

Don’t wait for a flat battery to catch you off guard—book a battery check with Tynan Motors today!

Ensure you search the Tynan stock through our link here.

Credit: MyNRMA.com.au