Start/Stop System and Start/Stop Battery

The Start-Stop system means that when the car is at a standstill, the engine stops running. During the shutdown, the lubricating oil in the engine continues to flow to keep the engine lubricated. When the brake is released, the engine starts again. At this time, due to the constant circulation of the lubricating oil, even if the engine is frequently stopped and started, the inside of the engine does not wear out.

Working Principle

We will simulate the operation of the start-stop system when a car passes through a road junction. Having described this, you should quickly understand how the start-stop battery system works.

The driver sits in the cab. A red light is on at the intersection ahead. The driver presses the brake pedal and stops to shift into gear. At this time, the Start & Stop system automatically detects that the engine is idling and no gear is engaged. The anti-lock braking system wheel speed sensor shows zero. The electronic battery gauge indicates that there is enough charge for the next boot. When these three conditions are met, the engine will automatically stop.

When the green light comes on, the driver depresses the clutch to start the “start-stop” and quickly starts the engine. The driver turns on the gear, presses the gas pedal, and the car starts up quickly. With the support of efficient battery technology and an appropriate engine management program, the start-stop system can operate normally at low temperatures and activate after a short preheat.

Advantages and Disadvantages of Engine Start-Stop Function


This can reduce unnecessary fuel consumption and emissions, and improve fuel economy. When waiting for signals in city traffic or stuck in a traffic jam, the engine idling time can be reduced as much as possible. The power supply can replace the engine cooling fan pulley and car air conditioner to provide working power after the engine is turned off.


Need a stronger starter and battery. The general design of the starter allows a large operating current, but the service life is short. Repeated use of the starter may cause damage to the starter due to overheating, so the automatic start and stop function of the starter must be more durable than a conventional starter. At the same time, due to the increase in the charging and discharging time of the batteries, the service life of the batteries is also reduced.

Start/Stop EFB/AGM battery

There are EFB and AGM Start/Stop batteries that are suitable for different types of vehicles with Start/Stop systems. Here, let’s talk about some of the differences between EFB and AGM batteries which are as follows:

  • EFB start & stop battery:

It uses advanced high liquid battery technology and the EFB battery is based on traditional battery technology. The EFB battery improves the battery’s deep-cycle performance by adjusting the active material formula. In addition, the increased strength of the assembly of the inner pole group allows the battery to have higher seismic performance while increasing its service life. Prevent the battery active material from falling off, extend the battery life by more than 2 times, and improve the battery charging responsiveness.

The EFB wet battery is suitable for installation near the engine compartment (wet battery with filler hole), high-temperature resistant, and repairable. Even Japanese cars are equipped with EFB batteries.

  • AGM starting and stopping battery:

AGM is a glass fiber adsorption separator technology. The AGM battery uses a barren solution type design, the plate is not impregnated with electrolyte, in addition to the plate inside partially absorbing the electrolyte, most of the electrolyte adsorption on the porous glass fiber, and the tight assembly technology is used to save the baffle. a percentage of the space is not occupied by a liquid electrolyte, which can increase the life of a deep cycle battery (three times) and the overall battery life.

A lean AGM battery should avoid high temperatures suitable for room temperature conditions under the seat and trunk. In Europe and America, more expensive cars are equipped with AGM.

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