What happened on one cold Adelaide Monday
In May 2025, on a Monday when morning temperatures fell to near freezing, RAA patrols replaced 333 car batteries across metropolitan Adelaide. Their daily average is 152. The suburbs with the most failures were Parafield Gardens, Morphett Vale, Prospect and Happy Valley, so it reached the north, the south and the middle of the city.
RAA's explanation is that extreme temperatures affect a battery's chemistry and cut its output, and cold thickens the engine oil so the starter has to work harder. That cold snap came after a long, warm summer. A battery can seem fine through the warm months and still be too weak for the first sharp drop.
Why Adelaide is hard on batteries
The summer heat
Adelaide usually has several days of 40 °C or more each summer. RACV says hot weather weakens battery performance, and suggests parking in the shade or a garage where you can.
Short trips
RACV says trips under 20 minutes don't give the alternator long enough to recharge the battery. In a city long known for twenty-minute trips, a car that only does short runs may never fully catch up.
Hills mornings
The Adelaide Hills run a few degrees cooler than the plains, and snow falls there roughly once every three to four years. A tired battery in Stirling or Mount Barker is likely to give itself away before one down on the coast.
Signs the battery is on its way out
- The engine turns over slowly or hesitates, especially on a cold morning.
- The lights look dim, the wipers are slow, or the radio and remote locking cut out.
- The car only clicks when you turn the key or press start.
- It's needed more than one jump start lately.
- There's white or green crust on the terminals, or the battery case looks swollen.
Before anyone jump-starts it
Don't jump-start a battery that's cracked, leaking or smells of rotten eggs. NRMA calls jump-starting a modern car a high-risk job, because a spike can damage the car's computers, so use spike-protected leads or a jump pack and follow the order in the handbook. A jump start may get you home, but it won't fully recharge the battery.
Test first, then replace
Slow cranking can also be the alternator, so the mechanic should test the battery and the charging system before fitting anything. RAA says a car's charging system only replaces the charge used to start it. It isn't built to bring a flat battery back, which is why a jump start alone rarely fixes things.
The new battery should match the size and terminal layout and have the same or a higher cold cranking amps (CCA) rating. Stop-start cars and hybrids generally take an AGM battery, and some newer cars need the new battery registered to the car's computer once it's in.
What we'd do
If the battery is about three years old or more, we'd have it tested at whichever service falls in autumn, before the first cold morning tests it for you. If it's already flat, we'd have the charging system checked at the same time, so a new battery isn't blamed for an alternator fault.