Battery advice.

[Matt58]

also see

E55 AMG Wagon Mystery Parasitic Battery Drain | Electronics and Audio

Please can anybody help? My 2003 E55 AMG S211 wagon has a mystery parasitic battery drain for years. Other W211, S211 owners must have suffered frustrating and time consuming battery drains? It draws key-off, and gone-to-sleep, 350mA on my meter when the specification is 40mA to 60mA maximum...

forums.mbclub.co.uk

Thanks, a really interesting read, I think I’ll invest in a new alarm siren. Interesting that not having keyless (I don’t) can still cause issues. I’ve also removed fuse fuse for phone and other fuses such as command to get draw down to 0.06. The only other problem I had was completely shutting the sunroof which I eventually got flush, so maybe it’s still trying to shut? Anyway I’ve removed overhead control mod fuse, and will try and sort when the warmer/drier days come. Looks like new battery and new siren, should I go oem or another brand?

 

[Bobby Dazzler]

Thanks for that. It's useful to know. I never know what to do so I keep my Ctek on "normal" charge all the time.

CTEK suggest running the Recond feature once each year, but only on standard Lead Acid batteries to keep them tip top.

Not for AGM or Lithium batteries though as the chemistry and make up is different and Recond mode would damage them.

 

[Headhurts]

In case you do get a CTEK, please not that you cannot use the Recond mode with an AGM battery, even though the CTEK device will allow you to select both Recond and AGM. The instructions specifically tell you not to, as the desulphation process can damage the fibre inside an AGM.

The instructions with the CTEK charger are very vague let me explain.

I purchased in July a 2021 GLC300 from Marshalls of Blackburn this car had only 2300 miles on it, the drive back to Norfolk is around 5 hours so plenty of time for the battery to charge.

I kept getting notifications of low battery state via the app, I charged it fully twice with the MXS 5.0 but I was still getting the warnings so I selected AGM & recondition then left it charging for around a day and a half, since running this program at end of July the car has run perfectly with no more battery warnings.

I have attached a photo from the book which shows bottom of page AGM with recon mode.

After reading your post and knowing from reading the forum you are pretty clued up I emailed CTEK support who replied and supported your comment.

I could be missing something obvious in the booklet (quite likely) but it is vague.

Robin.

 

[Bobby Dazzler]

The instructions with the CTEK charger are very vague let me explain.

I purchased in July a 2021 GLC300 from Marshalls of Blackburn this car had only 2300 miles on it, the drive back to Norfolk is around 5 hours so plenty of time for the battery to charge.

I kept getting notifications of low battery state via the app, I charged it fully twice with the MXS 5.0 but I was still getting the warnings so I selected AGM & recondition then left it charging for around a day and a half, since running this program at end of July the car has run perfectly with no more battery warnings.

I have attached a photo from the book which shows bottom of page AGM with recon mode.

After reading your post and knowing from reading the forum you are pretty clued up I emailed CTEK support who replied and supported your comment.

I could be missing something obvious in the booklet (quite likely) but it is vague.

Robin.

Robin; a few years ago I emailed CTEK to ask them to clarify the position regarding use of Recond with AGM modes and they confirmed that it shouldn’t be used with AGM batteries.

Personally I think it’s strange that the CTEK units will allow that combination of modes to be selected - and that it’s not made more clear in the instructions - if they recommend against it.

I’ve also read online that CTEK have told other people that they don’t recommend using Recond and AGM modes, but it doesn’t cause any harm. Given the lack of clarity, I’d avoid it.

 

[190]

In case you do get a CTEK, please not that you cannot use the Recond mode with an AGM battery, even though the CTEK device will allow you to select both Recond and AGM. The instructions specifically tell you not to, as the desulphation process can damage the fibre inside an AGM.

I presume the reasoning behind not wanting use the excessively high voltage charging used in reconditioning mode is that AGM's (and some others come to that) are Valve Regulated Lead Acid batteries, that is they are normally sealed except for a safety valve vent. If you over charge a VRLA it will internally gas off and up to a point recombine the gas back into the electrolyte. Grossly overcharging will cause the safety valve to blow with a loss of electrolyte than cannot be replaced. Do that often enough and the battery will fail. Gel batteries have a similar issue and don't respond well at all to overcharging although the more recent Gel/AGM hybrid batteries are much better in that respect.

 

[Matt58]

Found out today that the battery guarantee is three years not two, so I’m booking car in for free battery test, nothing to loss I suppose.

 

[Matt58]

Had battery tested at main dealer, and it’s a pass, pretty black and white in regards to explanation, it’s either a pass or fail, so fingers crossed it does not leave me stranded. Thanks for everyone’s comments and advice.

 

[Matt58]

Bit out of the blue, the parts guy at main dealers emailed me to say that after checking copy of invoice of battery I bought just over two years ago, was in fact the incorrect battery for my car. They will supply FOC a 100ah lead acid to replace 92ah AGM, any thoughts?

 

[AMGeed]

Bit out of the blue, the parts guy at main dealers emailed me to say that after checking copy of invoice of battery I bought just over two years ago, was in fact the incorrect battery for my car. They will supply FOC a 100ah lead acid to replace 92ah AGM, any thoughts?

Hmm I was always under the impression that the E55 required an AGM battery?
It's a good offer to replace what you have with a higher capacity one but I question it being a non AGM one.

 

[Matt58]

Hmm I was always under the impression that the E55 required an AGM battery?
It's a good offer to replace what you have with a higher capacity one but I question it being a non AGM one.

Yes, I was thinking along the same lines.