The first cold snap of the year across Australia’s eastern states has sparked an increase in roadside assistance for flat batteries. Here’s why.  
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Car batteries across Australia are conking out as the weather turns cold, with figures obtained by CarAdvice revealing a sharp spike in roadside assistance calls for jump starts in the lead up to winter.

Data from 2020 supplied by Australia’s three largest roadside assistance providers – the NRMA, the RACV and RACQ – show a clear increase in callouts for flat batteries at this time of year.

The NRMA – which covers NSW and the ACT – says it receives the most callouts for dead battery jump starts in April, May and June, responding to between 32,000 and 38,000 motorists in each of those months versus between 23,000 and 28,000 dead battery callouts for most other months of the year.

Even in warmer parts of Australia, car batteries seem to struggle with the seasonal drop in temperature.

Figures from Queensland’s RACQ show it replaced more than 17,000 car batteries each month in April and May last year, compared to 12,000 to 15,000 car batteries in most other months of the year.

Drivers in Victoria have a longer peak season when it comes to dead battery callouts, presumably because temperatures are colder for longer in the southern state.

Data from Victoria’s RACV shows the number of callouts for dead battery jump starts are highest in April and May (25,000 to 27,000 per month) while in June through October the roadside service provider receives between 21,000 and 23,000 calls per month for dead car batteries.

In warmer months the RACV only receives between 15,000 and 18,000 calls for dead battery jump starts.

The operations manager for NRMA roadside assistance, Craig Greenstein, says cold snaps can quickly kill a battery that’s on its last legs.

“In cold weather the engine is harder to turn over, so the battery has to work harder,” said Mr Greenstein.

“In summer, cars usually start more easily because there’s less internal resistance. In winter, a bit more energy is required to get the engine started and this puts increased pressure on the battery.”

Mr Greenstein says winter usually “sorts out the good from the bad” when it comes to car batteries.

“That’s why on the first cold snap we get a lot of callouts for flat batteries,” said the veteran technician.

He says most batteries in new cars should last three years on average, however some cars that are not driven often or mostly do short trips – and therefore don’t get much chance to recharge while driving – can conk out after two to three years, though this is rare.

Some modern cars require heavy duty batteries to be matched with their automated “stop-start” systems, which restart the engine multiple times on each journey, every time the car comes to a stop in traffic.

“They are a more robust battery but they generally last about three years as well, even though they work a lot harder throughout their lifecycle,” said Mr Greenstein.

The RACV says these heavy duty batteries – known as Enhanced Flood batteries – are generally 10 to 15 per cent more expensive than regular car batteries.

If a regular battery is used in a car that requires an Enhanced Flood battery, the RACV says it may cause the stop/start function to cease operation, will flatten quickly, and may not have adequate power to start a car.

As for preventative maintenance, there’s little motorists can do to avoid being left stranded by a flat battery, other than replacing it every three years before it conks out.

“Where possible it’s good to avoid short trips,” said the NRMA man. “Otherwise the battery doesn’t get a chance to recharge after using energy to start the engine.”

Mr Greenstein said if motorists need to reverse their car out of a garage to park it in the driveway, they should consider a brief drive around the block to give the battery a chance to recoup some energy.

The RACQ says the average life expectancy of a quality battery is three to four years, however if the battery is flattened and not recharged correctly, not secured in the vehicle properly, the vehicle is not driven regularly – or is submitted to temperature extremes – “the life expectancy can be shorter”.

“Vehicles not driven regularly should have a smart charger with trickle charge maintenance mode connected to ensure the battery is kept fully charged, otherwise it may fail to start the vehicle when required – and battery life may be shortened,” says the RACQ.

Giving a friend a jump start – or getting a jump start from another motorist – requires caution, say experts.

“With older cars it was relatively easy and harmless to do a jump start,” said Mr Greenstein. “But the batteries in modern cars are central to the vehicle’s electronic systems, and if the battery is completely dead there is a chance you could spike the engine management computer – unless you use surge-protected jump start cables.”

“Even with the right equipment you need to be very cautious,” said Mr Greenstein.

Road service providers such as the NRMA, RACV and RACQ typically have access to about 25 replacement batteries that are compatible with about 80 per cent of vehicles on the road, for instances where a jump start is not enough.

Mr Greenstein also said summer can play havoc with car batteries, but only on extremely hot days. “Even then we still don’t get as many callouts for batteries in the peak of summer as we do in winter,” he said.