A standard car battery usually lasts three to five years in Australia, and an AGM battery five to seven years, according to the RACV. Sydney summers, lots of short trips and cars that sit unused can shorten that, so it’s worth testing a battery once it passes three years.
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What shortens battery life
- Heat. High under-bonnet temperatures speed up the chemical wear inside a battery, so summer often does the damage that a cold morning later exposes.
- Short trips. Starting takes a lot of charge, and a ten-minute drive doesn’t give the alternator time to put it back.
- Sitting unused. Modern cars draw a small current even when switched off. Left for weeks, a battery can drain completely.
- Accessories. Dashcams and other hard-wired devices can drain a battery overnight.
- The wrong battery type. Stop-start cars need EFB or AGM batteries; a standard battery wears out quickly in them.
- Loose mounting and corrosion. Vibration and dirty terminals both shorten battery life.
Warning signs your battery is on the way out
- The engine cranks slowly, especially on cooler mornings
- Clicking when you turn the key
- Dim or flickering lights at start-up
- The battery warning light comes on
- Stop-start stops working
- The battery is swollen, leaking or more than three to four years old
A slow start can also be the starter motor, and a battery light while driving usually points to the alternator. See car won’t start but the lights come on.
How to make your battery last longer
- Drive for at least 20–30 minutes regularly, or use a smart charger if the car sits for weeks.
- Keep the terminals clean and tight, and the battery firmly clamped.
- Switch off accessories before turning the engine off.
- Replace it with the correct type for your car — especially stop-start models.
- Have it tested once it’s three years old, and before long trips.
Replace or recharge?
A healthy battery that went flat because something was left on can be recharged. One that fails a load test or keeps going flat needs replacing — or, if it’s fairly new, the charging system needs checking. BOSS 1 tests the battery and alternator where your car is parked and replaces the battery on the spot if it’s needed. See what affects the cost of a replacement or our mobile battery service.
