Hello to everyone,

I have been browsing the forum as a guest for quite some time and found many posts useful. I joined today to ask the community about a problem I have encountered with my C180 (W206), which has not been solved up to now.
I purchased the C180 in February 2024 (new from the local dealership), the car was built in the summer of 2023. Initially, I considered ordering a car with the additional equipment I would like to have, but due to long delivery time and a substantial discount on this already imported car, I decided to go for it.

I didn't encounter any problems up to the end of December 2024. As I use the car only for long distances, and not for driving around through the city because the size is not convenient, normally I travel about 300 km per week, these in a day or two. Then the car remains parked in a closed garage for about 6 to 7 days. At the end of December 2024, I received a message in the Mercedes app that the 12 V battery was low. This was the first time, the months before that the menu shown the battery fully charged even when I was abroad and the car was left for more than two weeks without driving it.

This behavior continued and now after five to six days the battery is at a critical level. I had the car checked at the dealership and they consider this a normal behavior. Their advice was to drive the car more frequently or to use a trickle charger.
I did use a high-end charger/trickle charger suitable for 12 V AGM batteries and it took a much longer time than expected based on charger specs to fully charge the battery (it was in moderately charge state when charging started).

Then, other problems started appearing, even though the battery appeared to be fully charged. The parking sensors lost part of their sensitivity and they operate much later than before. I noticed that because I have to maneuver the car through narrow space to park in my garage. Also, I drove the car for ~300 km and the lane keeping sensors and blind spot assist were not active at all. Then, suddenly, started working again. The car was restarted in between without any change. I contacted the dealership and they consider this to be due to not driving the car frequently (the battery was fully charged when this happened).

Now, after a day it becomes moderately charged, then with the car parked fully charged (!) without any charging, and then discharges again. I measured the voltage using a multimeter for some days and the reading were the following:
12.37 V (fully charged message, a few hours after driving the car for ~300 km)
11.97 V (moderately charged message)
12.30 V (fully charged message, with the car parked)
12.06 V (moderately charged message)
12.34 V (fully charged message)
11.71 V (moderately charged message)
Then drops further to low and critically charged state.

Next week the first service will take place and they will check the car again.

Did anyone have similar issues?
In my opinion, this is not an acceptable behavior for a new car. Any thoughts and advice would be appreciated.

 

A bad battery is not out of the question.

 

See if this helps:
https://mbworld.org/forums/new-membe...ml#post9118472
https://mbworld.org/forums/new-membe...ml#post9118476

 

Thank you for the response. I have read a number of threads related to starter battery problems. I will discuss possible causes with the dealership again next week.
Also, I tried using the "standby option" to stop the drainage of the battery, but it is greyed out and I was told that it is not included in my C180.

 

You're welcome. Hope they find the issue.

 

During the first service, a few error codes were cleared. The dealership acknowledged that the behavior of the car is not normal. Their proposal was to keep the car overnight, fully charge the 12 V starter battery using a charger and then run some tests. I was told this will not result in safety issues or damage anything, so, I will do this when convenient for me, as the dealership is an hour and a half away from home close to an occasional workplace of mine. I will inform the forum of the outcome in case someone encounters the same problem.

 

Show them the technical service bulletins I linked in the other threads.

 

For your convenience, here are the direct links to the PDF files:
https://mbworld.org/forums/attachmen...697d1740584374
https://mbworld.org/forums/attachmen...696d1740584190

 

I had the same problem on my 2023 C300. It was solved after couple of trips to the dealership.
TSB LI54.10-p-076820 version 7 was the one that fixed the issue.

https://mbworld.org/forums/c-class-w...w-battery.html

 

That TSB I never came across so thank you for posting.

 

@W205C43PFL and @giovane
Thank you both for replying.

For the time being, I do not have any TSBs. When I will visit the dealership again for the battery tests, I will ask for them and I will also show them the one that giovane posted.

Since, my last post, I left the car for 4 days with the trickle charger and then the "standby option" was enabled. So, it seems it was greyed out because of insufficiently charged battery, even though it appeared to be fully charged, both on the app and when measuring the voltage with a multimeter. Anyway, I use the "standby option" now when the car is going to be parked for more than 3 days.

 

I see, hopefully the dealership can update the software to fix it completely soon.

 

When are you taking the vehicle in to address it?

 

Probably during the summer. The warranty provided by Mercedes is up to February 2026. Then, I have an extension for two more years, but it is provided by a third party with modified terms and conditions.

 

I see, perhaps the visit isn't the worth the time off and rescheduling plans to bring it in until then?

 

These messages just popped up on my MB App.

I guess MB will replace the battery for free, since I’m still under the factory warranty

 

Uh oh, how is your driving like? Bumper to bumper, highway? If so how long? What is the distance?

 

They need to replace the battery under warranty if it is already degraded in such short timespan, it might had been defective.

 

I have the same message, except that my State of Charge is Partial.

 

Highway mostly, 20k miles a year.
My battery should be always charged.

 

The car is functioning properly, except for the battery issue, and had no problem starting the engine even with the battery at a critical state. So, it can wait for the time being.

 

@giovane and @Steely

Could you please let me know where the State of Health is in the app?

I cannot find it anywhere in my app. Maybe not displayed in Greece

 

It is not a part of the app, it is a part of the error message. If you get the low battery warning and click on it, you will see the screen we are talking about.

 

I never really seen the "state of health" before so interesting now it tells you how healthy the starter battery is.

 

Highway driving is usually the least stress and most healthy for the 12V battery as the alternator is usually more consistent with charging and no weird surges, I am confused why is your battery in a "bad health state". I don't see any signs of neglect.