Battery Failure (Rejuvenation) on 2004 CLK 320

[CleverPixel]

Greetings, forum members, I am seeking assistance and hope that someone can provide it.

I am attempting to restore a 2004 CLK 320 Petrol vehicle that has been inactive for about one year. Approximately four years ago, I had a fresh battery installed in my vehicle. I used to drive it once a week, but regrettably, I have not taken care of it since last year.
The Yuasa 9000 battery has been completely discharged and is assumed to be non-functional. I attempted to restore its functionality using an AA Intelligent charger in recovery mode. Surprisingly, the charger managed to fully recharge the battery within a few days.
After reattaching the battery to the vehicle, I saw many erratic lights flashing and the dashboard clock malfunctioning. However, I successfully managed to start the car and restore the window settings.

Nevertheless, after around 5 minutes of idling, the automobile abruptly ceased functioning. Upon attempting to start the automobile once more, I encountered a persistent noise as the engine made repeated attempts to ignite, lasting around 4-5 seconds. However, the engine failed to fully engage and subsequently shut off again.
The battery's initial voltage was around 12.6V, and when the engine began for the first time, the voltage increased to 13.6V while the engine was running.

Does it seem that the battery is still defective, even after it has been 'recovered' during charging?
I am open to replacing the battery and proceeding with a comprehensive service and MOT to get the vehicle back on the road. However, I would want confirmation from someone that the issue is most likely due to a faulty battery and not any other potentially malicious cause.

Thank you in advance

[CleverPixel]

Here is a video showing the car's attempt to start, in case it is beneficial:

https://www.kapwing.com/videos/64721336668b2a01f064eb50

[tr4s]

The most effective method to assess the battery is by measuring the terminal voltage while it is under load.
What is the voltage throughout the process of trying to start the engine?

[AmericaMonster]

It seems that you have a non-functioning cell. You may remove the caps from the top to see whether there has been any water loss. If you own distilled water, you have the option to include it. Once the water level is appropriate, reseal the cap and transport the battery to the closest automotive shop for recycling and purchase a replacement.

[tr4s]

An impaired cell will undergo thermal agitation when subjected to a heavy load.

[Banman]

Based on the description, it seems that the engine is rotating at a sufficient speed to initiate the ignition process.

Contaminated or impure gasoline 🤔

[SlayNeo]

Although the battery seems to be in good condition, it is advisable to verify the voltage when it is under load to ensure its proper functioning.

What is the current gasoline level in the tank? I am inquiring because if the fuel level is low and the tank breather has not been completely sealed, the volatile components in the fuel required for cold starting may have partially evaporated. This could result in a successful initial start using the fuel in the lines that are not exposed to the atmosphere. However, after running for a short period, there may be difficulty starting again as the fuel from the tank is utilised. If the gasoline level in the tank is low and the concentration of volatile compounds in the fuel is also low, then adding a substantial amount of fresh fuel might potentially resolve the issue. Even if it does not resolve the issue, you will have the assurance that your gasoline is of satisfactory quality.

Nevertheless, if the automobile operated smoothly for over thirty seconds after the first start, it indicates that the gasoline quality is satisfactory, at the very least.

[CleverPixel]

I appreciate the feedback from everyone.
I suspected that the issue may be related to the gasoline, considering that the fuel indicator was on when I first started the vehicle yesterday. Upon reflection, it is likely that the car was operating on a very low amount of fuel yesterday before it abruptly stopped.
Today, I added 4.5 units of super unleaded fuel to it using a jerry can. The vehicle was activated, prompting me to cautiously manoeuvre it in both forward and reverse directions on the driveway in order to assess the functionality of the brakes and other components. I traversed a distance of around 2 metres in a back-and-forth motion before the device abruptly ceased functioning and failed to restart. I physically disengaged the shift lock to move the automobile into neutral, allowing me to push it back into its original position.

Do you believe it is worthwhile to add an additional four half litres of fuel to the vehicle tomorrow and make another try to start it?

Thank you.

[SlayNeo]

It is advisable to attempt, even if it does not achieve the desired outcome.

[CleverPixel]

This morning, I supplemented my fuel tank with an additional 4.5 litres of super unleaded petrol. Prior to starting the vehicle, the battery displayed a voltage reading of 12.54V. Upon the car's ignition, I proceeded to inspect the battery and saw a voltage reading of 14.4 volts. Suspecting a gasoline shortage, I proceeded to remove debris from the vehicle. However, after around 5 minutes of idling, the car abruptly halted and refuses to start again, similar to what happened yesterday.
The dashboard displayed a red battery indicator, indicating the need to bring the automobile to a repair. As a result, the yellow engine light has illuminated.
Does this imply that the problem is associated with the battery? If so, I can get a new one for £130 and have it installed at home, along with doing a reset.
Just to inform you, when the battery was last changed 4 years ago, it seems that the vehicle was not reset or programmed to the new battery. Could this be relevant to the current issue?

Thank you.

[Racerse]

The voltage drops to 12.54 volts when turned off, indicating that the battery is around 90% charged. When running, the voltage increases to 14 volts, which seems OK. However, the engine eventually shuts down, suggesting a possible problem with fuel supply.
Possible cause: Fuel filter obstruction.
The fuel pump is experiencing diminished performance.
For the following instance, try running the engine without the fuel cap to test the effectiveness of fuel tank ventilation.

The ignition circuit is experiencing a breakdown due to the increase in temperature (heat soak) damaging a component.