What a Brisbane summer does to a battery
Heat, not cold
NRMA says extreme heat or cold can shorten a battery's life, and here it's the heat. Most summer days peak somewhere from 27 to 33 degrees, and a car parked in the sun all afternoon is hotter again under the bonnet. RACV's advice for hot weather is to park in shade or a garage when you can.
How long they tend to last
RACQ, Queensland's motoring club, has put the average battery's life at somewhere between 38 and 48 months. If yours is older than that, get it tested before summer rather than after the first morning it won't start.
Short trips and stop-start
RACV says trips under 20 minutes don't give the alternator long enough to recharge the battery, and a lot of inner-suburb driving is exactly that. RACQ adds that stop-start systems put extra stress on the battery.
Flat on the street
If it goes flat in the City of Brisbane, council's local law treats charging a flat battery as an emergency repair, which is allowed on the road. Bigger jobs on the car have to come off the street.
Battery, alternator, or something draining it?
A battery that keeps going flat isn't always a bad battery. Slow cranking and fading dash lights can also point to a failing alternator, and a meter test tells the two apart. Dash cams, trailer brake controllers and other add-ons can drain a battery while the car sits, too.
Newer cars need the right battery. AGM batteries suit hybrids and cars with stop-start, some cars need their electrical system reset after a new battery goes in, which is called battery registration, and some European cars have a second battery tucked away. Give the mechanic the exact model so the right one turns up.
What you can do, and what to leave to the mechanic
You can
- Park in shade or a garage on hot days when you can.
- If the car mostly sits, drive it for at least 20 minutes once a week.
- Lock it, even in the garage: RACQ says a car with keyless entry that's left open stays awake looking for the key.
- Note when it's slow to crank and whether any light comes on.
Leave to the mechanic
- Testing the battery and the charging system.
- Fitting a battery of the right type, size and cranking rating.
- Battery registration, on cars that need it.
- Jump-starting a modern car. NRMA calls it a high-risk job because the leads can damage the car's computers, and a cracked, swollen or leaking battery should never be jumped.
Where we'd start
If the battery is more than three years old, we'd have it tested in spring, before the heat sets in. The test takes minutes, and it beats finding out in a shopping centre car park on a 33-degree afternoon.