Many Perodua owners switch off the Eco Idle feature because they believe it shortens battery life. Is there any truth to this claim? The short answer is yes. However, a more complete explanation reveals how this automatic engine start-stop system actually works. Modern start-stop systems are designed to operate with batteries specifically developed for this purpose.
Eco Idle puts stress on the battery
Every time the car stops at a traffic light, the engine shuts off automatically. However, the battery continues supplying power to essential electrical systems such as the infotainment system, lights, and air conditioning. When you release the brake, a signal is sent to restart the engine, and the battery must deliver a high burst of current to crank the engine again.
Researchers refer to these frequent short engine restarts as microcycles, and batteries in Eco Idle systems can experience thousands of them over their lifetime. This is very different from normal driving conditions, where the engine runs continuously for longer periods, allowing the alternator sufficient time to recharge the battery.
Laboratory tests show that if a standard automotive battery is used in an Eco Idle system, its lifespan can drop significantly to around 7 months compared to the typical 3 years. This highlights why conventional batteries are not suitable for start-stop technology.
Why short trips are worse for Eco Idle systems
If your daily driving involves short distances or frequent traffic stops, the battery is placed under even higher stress.
Each engine restart requires the alternator to recover the energy used from the battery. On short trips, this recovery may not be completed, meaning the battery is repeatedly subjected to microcycles without being fully recharged. Over time, this leads to a sustained undercharged state, which encourages sulphate crystal formation inside the battery.
This sulphation increases internal resistance and permanently reduces the battery’s capacity. In hot climates like Malaysia, where temperatures can exceed 35°C, the effect is further accelerated, leading to a shorter battery lifespan overall.
AGM & EFB batteries for Eco Idle systems
Because Auto Start-Stop systems place higher demands on batteries, manufacturers have developed more durable battery technologies to cope with the load.
For example, Enhanced Flooded Batteries (EFB) offer significantly better cycle life than standard batteries, while Absorbent Glass Mat (AGM) batteries can withstand thousands of charge-discharge cycles.
Some advanced systems even use hybrid setups that include a capacitor to store charge specifically for engine restarting. This helps reduce the stress placed on the main battery during ignition.
This is why using a standard battery in a car equipped with Auto Start-Stop is not recommended, even if it appears more cost-effective initially.
Astra Battery offers both AGM and EFB options suitable for vehicles requiring these technologies. You can refer to the Astra Battery catalogue for more details.
Should you turn off Eco Idle?
Eco Idle can be turned off, but doing so means losing the fuel-saving benefits it provides. More importantly, disabling Eco Idle does not automatically extend battery life. Battery durability still depends heavily on driving habits. Short-distance driving, long periods of inactivity, or using an incorrect battery specification can still shorten battery life even without Eco Idle enabled.
The most effective way to maximise battery lifespan is to use a battery that matches the vehicle manufacturer’s specifications.
References
- Bishop, J., Nedungadi, A., Ostrowski, G., Surampudi, B., Armiroli, P., & Taspinar, E. (2007). An Engine Start/Stop System for Improved Fuel Economy (SAE Technical Paper No. 2007-01-1777). SAE International.
- Farrag, M. (2024). Development of Battery-Supercapacitor Management Systems for Electric Vehicles Doctoral dissertation, Brunel University London.
- Horie, S., Shimoda, K., Sugie, K., & Jimbo, H. (2007). Lead acid battery for idling stop system. In 2007 Power Conversion Conference - Nagoya (pp. 1352–1356). IEEE.
- Kollmeyer, P. J., & Jahns, T. M. (2019). Aging and performance comparison of absorbed glass matte, enhanced flooded, PbC, NiZn, and LiFePO4 12V start stop vehicle batteries. Journal of Power Sources, 441, 227139. https://doi.org/10.1016/j.jpowsour.2019.227139.
- Lee, S., Cherry, J., Safoutin, M., & McDonald, J. (2017). Modeling and Validation of 12V Lead-Acid Battery for Stop-Start Technology (SAE Technical Paper No. 2017-01-1211). SAE International. https://doi.org/10.4271/2017-01-1211.
