Mercedes CLS55 Battery questions

[andy27168]

so what battery did you buy in the end Andy?

Strangely I have my ctek wired into the pos & neg terminals of the battery via the quick release connection - My current battery throws a red light on the charger when it reaches step 5 on the Ctek - manual states my batt is not holding a charge properly

Looks like I may need one too

I ended up buying a Varta AGM Battery (019), since fitting I have not seen the convenience functions disabled message at all, has been left for two weeks not being used.
Incidentally I thought I would start checking for the battery drain, yesterday after a STAR session, I left the boot lid open used a screwdriver to throw the boot latch over so the car thinks the boot is shut, put on my Ammeter on the -VE of the battery and a I now have a drain of only 30-40mA which is within spec (MB say it should be less than 50mA). The only thing I did when connected to STAR was cleared all the fault codes, and re-started the fibre optic ring of the Command system, whether doing this was responsible for the drain I do not know, wish I had done the test before connecting to STAR now.

 

[Will]

As a follow on from the previous page, my E55 has a regular lead-acid 100Ah battery (genuine MB), it's not a daily drive and regularly goes several days without being used, I can't remember the last time I saw the convenience message, probably over the Xmas period where it had done several short runs and with freezing temperatures/infrequent use before hand ?

As above - I have also left it for 2 weeks plus when on holiday without issue and regularly goes 1 week plus no sweat. Has never, ever gone flat on me either.

I suspect any healthy battery of the correct capacity (Ah) would be okay, the AGM possibly recharges quicker in theory but if you've got a parasitic current drain you're going to have problems anyway.

At half the price of the AGM version (that MB don't supply any more?) I think I'd use the extra cash for something like a new alarm siren or front battery instead if required!

If it only last 18 months I've literally got weeks left, will let you guys know. MB do a 2 or 3 year warranty on batteries anyway AFAIK?

Whitenemesis - if your battery failed after 18 months and MB fitted it, did you not get them to replace it?

 

[whitenemesis]

It didn't fail, just started showing convenience off messages again. Charging system checked ok as did battery. I could leave it a couple of weeks ok, it started first time but message would still appear, just took longer to go.
CTEK took all the uncertainty away.

 

[Will]

It didn't fail, just started showing convenience off messages again. Charging system checked ok as did battery. I could leave it a couple of weeks ok, it started first time but message would still appear, just took longer to go.
CTEK took all the uncertainty away.

What changed over 18 months then - I was under the impression from what you were saying that the battery stopped performing as it should?

What prompted the first replacement and did that not help with the issue?

 

[whitenemesis]

What prompted the first replacement was the convenience messages but the battery supplied with the car was a no-name of dubious heritage (by the looks of it anyway). I didn't test the battery, so may have done it an injustice

The new battery certainly kept the messages at bay for a good while and when they came back I had both the battery and the charging circuit tested. Both passed with flying colours.

I had the BCM flashed with the most up to date coding, made no difference. Speaking with my bro'in-law (he managed the main dealer service centre in Bangkok) he said it was a very common occurrence with the W219, especially the AMG. He said they never knew why and simply advised using a trickle charger. The majority of cars did very low miles and then only short journeys which never helped with battery management

 

[Will]

What prompted the first replacement was the convenience messages but the battery supplied with the car was a no-name of dubious heritage (by the looks of it anyway). I didn't test the battery, so may have done it an injustice

The new battery certainly kept the messages at bay for a good while and when they came back I had both the battery and the charging circuit tested. Both passed with flying colours.

I had the BCM flashed with the most up to date coding, made no difference. Speaking with my bro'in-law (he managed the main dealer service centre in Bangkok) he said it was a very common occurrence with the W219, especially the AMG. He said they never knew why and simply advised using a trickle charger. The majority of cars did very low miles and then only short journeys which never helped with battery management

What I'm getting at is although the battery may have passed a particular test (load test?) going by what you're saying it wasn't performing optimally anyway, hence the drop in performance over 18 months. Maybe charging up okay and able to supply enough current for the test but still self discharging quicker than it should have when left sitting for a while.

I appreciate what your brother in law said to you, but with respect, even he said he didn't know what was causing this discharge issue, and how is an AMG different electrically to other similar 219s?

A trickle charger will obviously help but I'd personally rather find out the cause of the issue and rectify it, and at £74 inc VAT if it needed a new battery once every 18 months even I wouldn't be too worried, about £1 a week or a tank of fuel etc.

If a new battery did solve the issue would it not be justifiable for MB to replace, bearing in mind they supplied and fitted for that reason to begin with?

 

[whitenemesis]

What I'm getting at is although the battery may have passed a particular test (load test?) going by what you're saying it wasn't performing optimally anyway, hence the drop in performance over 18 months. Maybe charging up okay and able to supply enough current for the test but still self discharging quicker than it should have when left sitting for a while.

I appreciate what your brother in law said to you, but with respect, even he said he didn't know what was causing this discharge issue, and how is an AMG different electrically to other similar 219s?

A trickle charger will obviously help but I'd personally rather find out the cause of the issue and rectify it, and at £74 inc VAT if it needed a new battery once every 18 months even I wouldn't be too worried, about £1 a week or a tank of fuel etc.

If a new battery did solve the issue would it not be justifiable for MB to replace, bearing in mind they supplied and fitted for that reason to begin with?

The AMG is identical, electrically, to other 219s but they tend to be driven less, not as a daily driver.

And yes, I think it would be justifiable for MB to replace but I couldn't be bothered and would rather have a fully charged, maintained battery. It always drove better after a good charge, just like after washing and polishing it.

Clearly there is an issue with the dual battery system on the 219, as witnessed by the numerous posts we read but there has never been a good reason given.

Another one of those MB 'characteristics' maybe?

 

[Will]

The AMG is identical, electrically, to other 219s but they tend to be driven less, not as a daily driver.

And yes, I think it would be justifiable for MB to replace but I couldn't be bothered and would rather have a fully charged, maintained battery. It always drove better after a good charge, just like after washing and polishing it.

Clearly there is an issue with the dual battery system on the 219, as witnessed by the numerous posts we read but there has never been a good reason given.

Another one of those MB 'characteristics' maybe?

I appreciate the electrical complexity of modern cars and MBs in particular, but if you know that a new battery solved this issue for 18 months I'd have just been inclined to replace it rather than plugging it in to charge up all the time.

They're not hybrids you know

 

[190]

They're not hybrids you know

Actually they are in a very minor way.

Modern alternator control aims to charge the battery on the over run when ever possible in order to improve MPG and emissions figures. It seems they also limit charging when the battery reaches 80% of full charge so it's not uncommon to finish a journey with the battery less than fully charged. I give my battery a top up charge every week and it always needs it.

 

[Will]

Actually they are in a very minor way.

Modern alternator control aims to charge the battery on the over run when ever possible in order to improve MPG and emissions figures. It seems they also limit charging when the battery reaches 80% of full charge so it's not uncommon to finish a journey with the battery less than fully charged. I give my battery a top up charge every week and it always needs it.

Nice info, but you can't drive a 219 CLS via the alternator can you?

I appreciate that the alternator will rarely charge a battery to the very last percent possible, but isn't that the case for nearly all cars? Whenever I've taken a battery off a car to store - and put it on for a maintenance/top up charge they've always taken more. What matters I guess is if the battery in whatever state of charge it's left at will be sufficient for the vehicle to perform as it should, the rest is academic

 

[Ted]

190 is correct. Modern 'intelligent' systems will only charge the battery to around 80% - depending on soh and temperature.
As you say, even older charging systems never fully charged them, to keep them from gassing, but they would generally keep them up in the nineties.
Also the intelligent systems will give staged charging - agm requires three or even four stages in the charging, where the older systems were much more linear.

 

[Lenny63]

I appreciate the electrical complexity of modern cars and MBs in particular, but if you know that a new battery solved this issue for 18 months I'd have just been inclined to replace it rather than plugging it in to charge up all the time.

They're not hybrids you know

MY CTeK has a very handy recondition mode
Which takes 2 days on these big batteries and is very worthwhile to complete every 6 months

 

[Lenny63]

I can get a 019 AGM from hellfrauds under trade discount for £144 with a 4 yet warranty - I know from experience Halfords stand by their batteries no quibbles

I'm almost certain Yuasa make Halfords batterie now

 

[Will]

MY CTeK has a very handy recondition mode
Which takes 2 days on these big batteries and is very worthwhile to complete every 6 months

Maybe WN can comment further but AFAIK he had a CTEK charger, so can confirm what methods he tried on his battery?

Regards the AGM/regular lead-acid battery option, does anybody know why MB stopped supplying AGM batteries for these cars?

Halfords batteries have always been pretty good as an aftermarket option, but for me in this instance the cost isn't justified. I'd rather pay half the price for a genuine MB battery and if need be replace sooner - even the AGM batteries don't seem to last as long as you'd expect?

 

[andy27168]

Hi,
On the CLS some still are shown as having an AGM Battery, others like mine they have updated to have a Lead Acid all according to chassis break point.
I did have a quick look to see what differences in the electrical system there was/is, but all I have established regardless of which battery is fitted the Alternator/Regulator pack is exactly the same.

 

[whitenemesis]

Maybe WN can comment further but AFAIK he had a CTEK charger, so can confirm what methods he tried on his battery?

I only ever used the 'Normal' mode on the CTEK

 

[Lenny63]

The theory behind the recondition mode according to the CTEK manual
Makes sense - I've done it once on my car and once on a previous

 

[AlanD]

Right, bit the bullet and got a new battery from MB today! We shall see during the week if the problem goes away. The old battery was lasting only up to 2.5 days after a full CTEK charge. Run dead flat a few too many times perhaps.

One question I have now that I'm home and have only just had a good look. My new battery has a "best before" date of Feb 2018. Is this normal? Is that just a sell before so the charge doesn't drop or should it be more like Feb 2028!?

 

[AlanD]

Any comments on the date? Here's a pic:

Annoyingly, they stick the local stickers right over the original MB ones with stuff that doesn't peel off!

 

[markjay]

...Annoyingly, they stick the local stickers right over the original MB ones with stuff that doesn't peel off!