The start-stop system is designed to save fuel by shutting down the engine when the car is stationary. However, drivers often worry about start-stop system damage, particularly the strain on the engine and battery caused by frequent restarts. In this article, we will explore how the system works, its potential risks, and whether these concerns are justified.

Understanding How the Start-Stop System Operates

The start-stop system works simply. When you stop and shift out of gear, the system shuts off the engine. Once you press the clutch to shift into first gear, the engine starts again.

This interrupts fuel consumption while the car is idle, reportedly saving 3% to 10% of fuel.

However, the situation isn’t that simple. We’ll explain when the start-stop system may not function as expected, as there can be significant differences between cars.

Engine and Battery Concerns with the Start-Stop System

Drivers are most concerned about potential damage caused by frequent engine starts and stops. Cold starts are especially harmful to the engine. In addition, the starter, which normally engages the engine five times a day, might need to do so up to 100 times. Not to mention the battery, which must supply enough power for this frequent engine start-up.

There’s also the question of what happens when the engine shuts down but the headlights, wipers, radio, and rear window defrosters continue to work.

For more details on whether the start-stop system damages the engine and battery, check out this article.

The Starter: Durability and Performance Under Strain

Because the starter in cars with a start-stop system must engage much more frequently, it’s designed to withstand far more starts. In some cars, the entire starting system is different, so manufacturers claim drivers don’t need to worry.

How Do Start-Stop Systems Protect the Battery from Damage?

Many drivers fear the battery will quickly wear out if the engine isn’t running but devices like lights, multimedia systems, wipers, and defrosters continue to work. However, the engineers who designed start-stop systems anticipated this issue.

First, cars with start-stop systems use special batteries suited to these conditions, though they are more expensive.

Second, the system monitors battery status. If the battery level drops below a certain threshold, the engine restarts.

Third, the charging method for these batteries differs from standard ones.

Standard Batteries vs. Specialized Start-Stop Batteries: Understanding Compatibility

Can You Use a Standard Battery in a Car with a Start-Stop System?

No, you shouldn’t do that for several reasons.

Yes, a standard battery might work in an emergency, but there could be negative short-term and long-term effects, depending on the battery type and vehicle. Basic start-stop systems use EFB batteries, while advanced systems with regenerative braking use AGM batteries.

We won’t get into the differences compared to standard batteries now. Simply put, start-stop batteries are designed to handle charging and discharging conditions that would quickly damage a regular battery.

In summary:

a) A standard battery can fail quickly in a car with a start-stop system. If this happens, it will be hard to claim the warranty, even if you hide the fact that the car has a start-stop system.

b) Ideally, the battery monitoring system (BMS) will detect an inappropriate battery and adjust the start-stop system to its lower capacity.

For example, during engine shutdown, some non-essential functions, like seat heating, will automatically turn off.

c) The system may also deactivate the start-stop function to prevent battery damage and keep the car operational. This means the engine won’t shut off when you stop.

d) Due to battery and system incompatibility, the battery’s lifespan could be significantly shortened, even with the start-stop system disabled.

e) In the worst case, the battery could suffer physical damage, although there are no known cases of this happening.

How the Start-Stop System Functions in Everyday Driving

The start-stop system relies on multiple factors. Some drivers believe their system isn’t working correctly if it doesn’t shut off the engine every time they stop or occasionally starts the engine while stopped.

The system gathers data from numerous sensors and systems, and the computer uses this information to decide when to stop or start the engine. We’ll explain this in detail in a future article.

Reasons Your Engine Might Restart While Idling at a Traffic Light

Several reasons might cause the system to start the engine while you’re stopped at a light:

a) You’ve moved the steering wheel, even slightly.

b) The cabin temperature has changed, requiring cooling or heating.

c) The battery has drained to the point where it needs recharging (this is common if many devices are running).

d) You’ve lifted your foot off the brake.

e) The car is on a slight slope, and lifting your foot off the brake has caused the car to move.

Addressing Concerns About Engine Lubrication and Wear

Drivers worry that when the engine shuts off, lubrication stops, and even a short period without oil can cause wear.

Experts say there’s no reason to worry because the most wear occurs during cold starts, where the engine has cooled, and oil has drained. Shutting off and restarting the engine every 10-30 seconds when it’s at operating temperature doesn’t cause significant wear.

Additionally, these cars use special oils with additives that help the oil stay on engine surfaces for longer.

Will the Start-Stop System Damage My Turbocharger?

Many turbochargers have water cooling systems that use coolant (antifreeze) to cool both the engine and turbo.

When the start-stop system shuts down the engine and stops the turbo, an electric water pump continues to circulate coolant through both, preventing local temperature spikes and oil burning in the turbo bearings.

Even with water cooling, the start-stop system might delay engine shutdown if you’ve been driving hard, allowing the engine to cool down.

Note that water-cooled turbochargers aren’t exclusive to cars with start-stop systems; many other cars, especially petrol ones, use them too.

Can I Permanently Disable the Start-Stop System?

No, as far as we know, no model allows permanent deactivation of the start-stop system.

You can temporarily turn it off by pressing a button, but it will reactivate the next time you start the car. There are tricks for permanent deactivation, but you’ll need to research those on your own.

Conclusion: Understanding Start-Stop Systems for Better Maintenance

Keep in mind that start-stop systems are constantly improving. If you had a bad experience with an early system, don’t dismiss the technology as unnecessary or a gimmick that only increases car prices.

Newer cars with modern start-stop systems often behave very differently from older models.

If you already have a car with this system or plan to buy one, be sure to read the vehicle’s manual and learn how the system works. This way, you’ll know what to expect in different situations and avoid unnecessary frustration and worry that something is broken.