I sent my car for servicing recently and was told the battery had to be replaced. It is a 21-month-old Mazda 6 which has clocked about 20,000km. According to the authorised workshop, the car's stop-start function does affect battery life. Will I need to replace the battery every 20 months?

The life of a car battery is determined by many variables. These days, many cars come with stop-start systems which require more powerful batteries. Such cars are also fitted with more efficient alternators and heavy duty starter-motors.

Although Mazda's i-stop system is claimed to rely on combustion to restart the engine rather than the starter motor, the battery nonetheless continues to supply electrical energy to various components when the engine is switched off and the alternator is not charging the battery.

This does suggest the stop-start feature could affect battery life.

But given Singapore's climate and largely urban driving conditions, it is not unusual for battery life to range between 18 and 24 months for cars fitted with a stop-start system. Those without stop-start should see the battery lasting 24 to 36 months.

Hence, if you want to preserve your car's battery life, you can choose to deactivate the stop-start function.