C250 W204 possbile battery issues

[samosaa]

I have 2012 w204 C250 which I think the battery is on it's way out but not sure which one.

Since March's lock-down, i was hardly using the car but when starting the car after a week or two of no use it was starting fine. As we came out of lockdown I recalled i have not seen the start/stop function throughout the whole of lockdown and thought it might just be down to short drives to supermarket the car didnt hit the requirement to stop/start.

It went in for a B service at Mercedes Brooklands in late July and no faults, only issue with the a screw holding the engine tray which they fixed as complimentary.

In October the vehicle went into limp mode and needed the intake boost pipe (forgive me if this isn't the correct technical name) changed and throttle valve seal replaced. When i picked it up from the garage, i noticed start/stop indicate was green and functioning again.

Vehicle has been in use twice a week since the most recently lock-down but last week in the morning it struggled for a split second to start and did the same this morning. Start/Stop indicator stays yellow and doesn't go green at all. In addition to this, the brake hold did not work but on the return trip, brake hold had returned.

Am i correct to assume its the Aux battery which needs replacing and located next to spare tyre in the boot. If so please can some recommend which replacement to get?

Any help will be greatly appreciated and thank you in advance.

 

[Gazwould]

I'd say it's main as HOLD has nothing to do with auxiliary .

There's alot of us in this boat with batteries all of a sudden .

 

[OneForTheRoad]

Charge the main overnight .

 

[geoffus]

Same problem for me a couple of weeks ago, car has not been used very much recently and did struggle to start on a few occasions, on one morning it didn't actually start at all.
I connected my trusty smart charger overnight and it helped next day as it was back to normal, week later started to struggle again.
I priced up a couple of AGM batteries on Ebay and even thought of using a non AGM basic battery as never use stop/start.
Then again left the charger on overnight on winter setting and since then its been perfect , even this frosty morning it was back to normal.
The main battery is the one you need to charge and you need a smart charger, Ctek are well known as one of the best, but I bought mine from Aldi and it works really well.

 

[OneForTheRoad]

Same problem for me a couple of weeks ago, car has not been used very much recently and did struggle to start on a few occasions, on one morning it didn't actually start at all.
I connected my trusty smart charger overnight and it helped next day as it was back to normal, week later started to struggle again.
I priced up a couple of AGM batteries on Ebay and even thought of using a non AGM basic battery as never use stop/start.
Then again left the charger on overnight on winter setting and since then its been perfect , even this frosty morning it was back to normal.
The main battery is the one you need to charge and you need a smart charger, Ctek are well known as one of the best, but I bought mine from Aldi and it works really well.

A lead acid battery will flatten alot sooner than your agm stop start battery . Its not all about stop start . Mercs without stop start like the w211 and w219 eat amps like pacman ate dots . Short journeys being the killer.

 

[Teego]

I suggest taking a simple approach. Drop in to your local Formula I, or similar, autocentre fast fit. They'll test your batteries for free and tell you what needs doing. I've found Formula 1 to be particularly honest.

 

[samosaa]

Any recommendation on which battery to replace with?

 

[wongl]

Any recommendation on which battery to replace with?

Buy the best battery you can afford from a trusted supplier. If your original is an AGM battery it would be unwise to fit a non-AGM as you will be making assumptions without all the facts and putting your expertise above and beyond those of the engineers at Mercedes-Benz. For example, as I understand this subject, the charging voltage for AGM batteries is slightly lower than non-AGM. I have not idea if this will make any difference to a non-AGM battery but this is only one potential fact that might be material?

 

[OneForTheRoad]

Any recommendation on which battery to replace with?

Theres not many to choose from tbh. Your battery tray is i think 315 mm long . So anything larger won't fit. Check your battery for a mercedes part number and go from there.

 

[Gazwould]

Highly likely .

 

[Flyinspanner]

If you look at photo in post #10, you can see the date on battery terminal post, 09/12 - the 9th week in 2012.

Batteries are pretty much done at 5 years. (Yes you may get longer, it’s just a rule of thumb).

many people will be getting issues as the cold weather has now arrived, and cranking through thicker oil, in cold temp is harder for the battery, and there are so many more demands on power circuits in cars these days, (with lots of wobbles if the voltage is unstable) if it’s weak nows the time it throws its hand in.

 

[geoffus]

Before spending £150 you will be better off getting a smart charger for £15. Charge overnight as they do work really well.
If that don't work then you need something like this

G14 Varta 017 019 AGM 12V Car Battery - Iveco Jaguar Jeep Land Rover Mercedes e | eBay

G14 Varta Silver Dynamic Start-Stop Plus AGM Car Battery 12V 95Ah (595901085) (019 AGM). In the vast majority of cases, yes it is! Because of this, we put all of our resources into getting you new battery out to you as quickly as humanly possible.

www.ebay.co.uk

Also turn your stop start off as soon as you can during small journeys.

 

[Gazwould]

Before spending £150 you will be better off getting a smart charger for £15. Charge overnight as they do work really well.
If that don't work then you need something like this

G14 Varta 017 019 AGM 12V Car Battery - Iveco Jaguar Jeep Land Rover Mercedes e | eBay

G14 Varta Silver Dynamic Start-Stop Plus AGM Car Battery 12V 95Ah (595901085) (019 AGM). In the vast majority of cases, yes it is! Because of this, we put all of our resources into getting you new battery out to you as quickly as humanly possible.

www.ebay.co.uk

Also turn your stop start off as soon as you can during small journeys.

Too big that one and 4 years !

 

[geoffus]

Too big that one and 4 years !

Just an example, it’s the one for mine.

 

[artyman]

I'm still on the original battery on my W204 from 2008, not sure if that's a record.

 

[Gazwould]

Very good , what voltage is it measuring ?

Mines 11.7 - 12.1V but isn't causing slow cranking yet and 500 CCA available from the original 800 .

Doing the research now as it's days are numbered .

 

[OneForTheRoad]

Just an example, it’s the one for mine.

Strange that , that battery is too big for my e350 , maybe because the the a207 and c207 are modelled on the w204 chassis ?? 315 mm battery tray.

 

[geoffus]

Strange that , that battery is too big for my e350 , maybe because the the a207 and c207 are modelled on the w204 chassis ?? 315 mm battery tray.

This is mine

 

[OneForTheRoad]

This is mineView attachment 105550View attachment 105549

I think you'll find that's 315 mm long.

 

[Kam55]

Charge the main overnight .

Do you remove the battery from the car and charge it at home or can it be done by opening the bonnet and connecting the charger to + and ground terminals? I have W219 chassis (CLS500) from 2005. I can see a big battery in the boot but not sure if it's main or aux. I have a charger, just not sure how to approach it