People blame winter for flat batteries, but in Australia it is the heat that does the real damage. Summer cooks a battery from the inside, and then the first cold morning finishes it off.
Why heat is the problem
High temperatures speed up the chemical reactions inside a battery and evaporate the fluid it needs to work. Under a bonnet in an Australian summer, temperatures get extreme. The damage builds quietly through the hot months, and the battery then fails when it is asked to do hard work on a cold start.
How long should a battery last?
Typically three to five years. In hot climates, closer to three. If yours is past four years old, treat every summer as borrowed time and get it tested rather than waiting for it to strand you.
Short trips are hard on batteries
Starting the engine takes a big chunk of charge, and it takes a decent drive to put it back. If your car mostly does five-minute trips, the battery never fully recovers and slowly runs down. A longer drive once a week helps a lot.
Simple things that extend its life
Park in the shade or in a garage whenever you can — it genuinely reduces under-bonnet heat. Keep the terminals clean; that white or blue crusty build-up is corrosion and it restricts current. Make sure the battery is clamped down tightly, because vibration shakes the internals apart. And switch off headlights, interior lights and accessories when you leave the car.
Warning signs
The engine cranks slowly or sounds laboured when starting. Headlights dim noticeably at idle. The battery or charging warning light appears. Electrical gremlins like the radio resetting. Any of these means get it tested.
Get it tested — it is usually free
Most battery retailers and auto shops will test your battery and charging system at no cost in a few minutes. Do it before a long trip and before the peak of summer. Replacing a tired battery on your terms costs far less hassle than replacing it on the side of a highway.
If the car sits for weeks
Cars that are parked for long periods slowly drain. A cheap trickle charger or battery maintainer keeps it healthy and is much cheaper than a new battery.