Hello, I purchased a new battery from a battery group around two months ago, since the stop/start function in my C-Class Estate S205 220d seems to be malfunctioning.
Upon starting the vehicle, the voltage reads 14.8V, indicating that there is no problem with the alternator. When I stop the automobile after it has been operating, the voltage reads 12.5 volts.
The problem arises when I leave the vehicle overnight; the battery shows a voltage of 11.5V upon re-entry.
Two inquiries are shown here -
1. Would you characterize this as a defective battery problem? Or an alternative. How can I do a test?
2. What should the starting voltage be when the battery is healthy, and what is the typical voltage while the engine is operating, considering that 14.8V seems excessive if the battery is in good condition?
Is the battery depleting? Class C S205
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godisgreat
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One must assess the battery to ascertain its functionality. I prefer a high-rate discharge tester, however there are devices that pump a signal into the battery for testing purposes. Halfords is likely to do tests at no charge, or a competent auto electrician may perform the assessment.
The voltages may be deceptive with 'intelligent' charging. The voltage may reach 15 volts or drop to 12 volts while the engine is operational, making diagnosis somewhat challenging. Are you aware of the accuracy of your voltmeter?
I used a USB power source that connects to the cigarette lighter and included a voltage display. You may thereafter get an understanding of the voltages while operating the vehicle. It generally peaks during overrun and decreases during acceleration, maintaining a range of 14-14.3 under standard driving conditions.
If the battery tests positively and the nighttime voltage registers at 11.5, I would anticipate a parasitic discharge.
My recommendation, for what it is worth, is to consult a reputable auto electrician and get their opinion.
The voltages may be deceptive with 'intelligent' charging. The voltage may reach 15 volts or drop to 12 volts while the engine is operational, making diagnosis somewhat challenging. Are you aware of the accuracy of your voltmeter?
I used a USB power source that connects to the cigarette lighter and included a voltage display. You may thereafter get an understanding of the voltages while operating the vehicle. It generally peaks during overrun and decreases during acceleration, maintaining a range of 14-14.3 under standard driving conditions.
If the battery tests positively and the nighttime voltage registers at 11.5, I would anticipate a parasitic discharge.
My recommendation, for what it is worth, is to consult a reputable auto electrician and get their opinion.
I own a voltage meter and a USB smoke charger that displays voltage. Additionally, one may monitor voltage on the Mercedes screen in a specific part, the name of which I cannot recall. It displays horsepower, torque, temperature, and battery voltage on the display.
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DivineStripe
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- Posts: 114
- Joined: Tue Feb 15, 2022 7:37 pm
I regret to learn that you could be experiencing difficulties. A few inquiries:
What prompted the purchase of a new battery two months ago?
2. Your phrasing in the previous message suggests that the stop/start function worked correctly until the battery was replaced; is that accurate?
What prompted the purchase of a new battery two months ago?
2. Your phrasing in the previous message suggests that the stop/start function worked correctly until the battery was replaced; is that accurate?
The battery was replaced due to persistent OBD errors indicating suboptimal battery health. The stop/start function has never worked with the old battery since I acquired the vehicle. I previously experienced inadequate fuel economy.
With the installation of a new battery, the alternator operated less intensively, resulting in improved fuel economy and effective stop/start functionality.
Recently, the automobile failed to start, necessitating a jump start. Since then, I have observed that the battery voltage consistently measures 11 volts before to starting the car each morning. Uncertain if the battery is defective or whether there is a power drain occurring.
With the installation of a new battery, the alternator operated less intensively, resulting in improved fuel economy and effective stop/start functionality.
Recently, the automobile failed to start, necessitating a jump start. Since then, I have observed that the battery voltage consistently measures 11 volts before to starting the car each morning. Uncertain if the battery is defective or whether there is a power drain occurring.
