Hello everyone, do i need to do anything specific to protect the memory or programming of my car before removing / disconnecting / replacing the rear battery.

 

no.... just don't short anything out - lots of big electrical connections above the positive terminal

the clock might go wrong as the car will forget which year it is - software patch available to fix that issue correctly

 

Nope. You just have to take out practically EVERY panel in the trunk!

 

thank you BOTUS and mikieb

 

my car had ONLY been serviced by main dealers - when I first tried to remove the part obscuring the rear battery, I found nothing retaining the trim panel.... now I think it might have had one small tab two thirds across from the bottom left on the base rear trim panel - third time doing the job I noticed a rough bit that sits near a spare bolt hole just left of the battery strap - maybe it shows as a plastic rivet part 230 below

without that pointless lug, you needn't remove any other trim parts or use any tools to reach the rear battery

should you fail to realise this and waste 2 hours removing cheap nasty trim parts, including the rear plastic boot load panel 30 (snapping all the clips), so you can start trying to remove the rear side panels, then the boot floor panel and the upper boot panel YOU WILL STILL FIND you can't get the rear panel out as its all jammed in and interlinked with each others fitment. The boot side panels wrap around the vertical edges of panel 225 (see pic) and so neither the sides nor the back will come out - you still have to force one part past the other - and the side trims are far more fragile than the rear panel... thus THE SIDE PANELS ARE BEST LEFT IN PLACE as you will do less damage

First ever time - take out the boot floor trim panel, to remove the rivet / clip and allow the lug room, then just drag the bottom right corner out, - then before refitting, remove the lug and smooth off any rough edges - this lug has no effect whatsoever - with this gone (as is likely, its already been snapped off by the last garage to work on it) - once any rough edges are smoothed off, every subsequent rear panel removal can easily be achieved without touching any other trim at all... just reach a fore finger under one bottom corner and pull the panel out (its a bit of a fight - but it will still be the same fight if you waste 3hrs stripping and fitting trim parts - but in your exhaustion you'll snag the metal bits I mention below)

On refitting -- regardless of wasting time with any other trim paneling - YOU MUST ENSURE YOU LOOK AND FEED THE TOP OF THE PANEL PAST TWO FLIMSY BITS OF METAL BRACKETRY THAT HOLD UP THE TRIM PART 220 or you'll snag and bend them out of place

 

Thanks again BOTUS very helpful

 

top tip to get the battery out --- park on the level... either carefully removing the short positive link from the battery module to the positive terminal OR tape the positive terminal liberally with insulating tape and tucking it out the way - reach in pop off the short white breather elbow just on the side of the positive terminal - it just wiggles out towards the inner wing - AND with the Boot floor trim panel still in place... place a robust plastic bag flat on the trim carpet, so you can simply slide the battery from its location on to the bag and drag both to the boot opening.... refit the same way - it weighs 23.5kg aka 52lbs !!!

 

Thanks BOTUS these practical experiences can make alot of difference for a first timer and save us from reinventing the wheel potentially damaging many other things.

 

assuming your car came with sat nav, when u have replaced (or disconnected) the battery, when back together, go in the comand system to settings, then date, and look at the year its displaying - if its not saying 2023 there's a small home user update disc to make that takes 8 mins to run so the car can tell the time and date correctly

 

Thanks again will revisit once the battery replacement process is over.

 

Dear BOTUS and mikieb managed to pull out the battery with no snags at all thanks to all your valuable guidance.

As i understand the AGM Batteries are more suitable to the Electrical and Electronic gadgets. However an AGM Battery requires a higher voltage for charging them fully apparently between 13.8V to 14.6V and a Floating Charge of 13.4-13.6V, failing which the Battery never charges fully and will eventually lose power. Can anyone advise what kind of charging voltage the alternator on this vehicle can produce?

 

My 2007 S600 puts out about 14.3 volts when running, warm, and happy in nice Autumn weather. In Summer, with A/C blasting and full fans going; she lists about 13.8 volts.

 

most alternators struggle to do lots at tick over - giving about 13.7v to 13.9v, hold the revs around 2k rpm and on weird modern cars often needs a few mins for it to understand the world and kick in - where you should see 14.2 to 14.5 volts

the odd thing about AGM was they were too good and lasted 12 years, and so obviously they dropped the quality lots, now they last 2 years working as normal and limp along a bit naff for another 3 years - and this is seen in the warranty, where AGM nowadays gets 3 years and other technologies can now get 5 years... when they were the ones that didn't manage 2 years in the past ???

 

thanks vettebk and BOTUS
so BOTUS you suggest going with a standard flooded lead acid battery instead?

 

just checked the big UK aftermarket motorist shop (our equiv of O'Reilly's - but from what I see on VGC theirs are miles better), they give some numbers (now bold below) that explains the world... whilst the early 221 are not start stop, the electrical loading is quite similar hence why the start stop battery was specified - thus use an AGM one - they were designed for military use and can withstand lots of abuse (both handling wise and in charge / discharge)

Calcium

These batteries offer a slight improvement on lead acid batteries thanks to their 4 year guarantee and a rating for around 30,000 starts. You'll also get 18% more starting power, which is handy on colder mornings when engines often need an extra kick to get going.

Yuasa Silver

Our top end calcium batteries come with a 5 year guarantee and are good for up to 50,000 starts. You'll also get an additional 33% starting power than you would with an ordinary battery.

AGM/EFB (start/stop)

If your car has start/stop technology (the engine switches off when you stop at traffic lights or junctions), then you'll need a different AGM or EFB battery. These batteries are a bit more expensive, but are a lot more durable, lasting for an incredible 360,000 starts! These special batteries may need to be registered with your car's on-board computer to work properly, so we'd recommend having them replaced by our in-store professional to make sure your start/stop function continues to work.

 

thank you BOTUS

 

hey Kalakov222, you didn't come back with the next question...

this is a process some cars use to tell the control module that fights the alternator, how it should do its job...
lots of BMW's use it, and it turns out its becoming more and more popular on the latest cars... (Alfa even use it) and in the early 2000's one Merc model used it, but this was before anyone had tools or knew some later madness over-complexifying cars had been invented. Its helps two ways, lets the alternator know what nasty battery you bought, and helps the battery last longer and stay tip top, because the algorithm of how its going to do the charging and the amount of charging can be fine tuned to the battery type now in the vehicle.... AKA high capacity AGM vs baby budget trash.

Funny enough and the reason I posted back - Snap On for their end of year diagnostic tools update for 2023.4 has JUST included Mercedes battery Registration !!!!!

https://www.snapon.com/Files/Diagnos...L83A_Final.pdf

Mercedes-Benz®
2013 – 2020 S Class® Front Signal Acquisition Module (SAM) Battery Registering Procedure
2002 – 2009 CLK® – Electronic Ignition Switch (EIS) Special Functions


.

 

Quote:

Originally Posted by BOTUS

hey Kalakov222, you didn't come back with the next question...

Thanks BOTUS these are the subsequent questions. Although I am afraid there are many more to follow.

[QUOTE= ...Can anyone advise what kind of charging voltage the alternator on this vehicle can produce?[/QUOTE]

Quote:

Originally Posted by ...so [url=https://mbworld.org/forums/members/317990-botus.html

BOTUS [/url]you suggest going with a standard flooded lead acid battery instead?

Although I have managed to recharge my starter battery and now also successfully ran a Recondition cycle (desulphate) on the Rear Bosch 100 Ah Electricals Battery which seems to be fully charged. NOTE: Both were discharged easily for a year could be more, I am going to run a load test on both before reinstalling them. I will get back here with an update.

 

a chassis decoder will say which alternator it came with, never seen one not say it came with a high output one
these car's eat more electricity than they do petrol - key on, engine off, makes 37 amps vanish, thus a brand new battery will struggle to last 30 mins
AGM batteries must NEVER be subjected to the Reconditioning (desulphation) cycle - read the manual for the charger

AGM batteries are supposed to have the lead trapped between a sandwich of moist glass matting (which stops the lead sludge falling off like it does in aged traditional batteries, and often shorting out in winter, going instantly dead), the issue is this water vanishes over the years and the electrical conductivity reduces. These have such a large battery if driven regularly most never notice the rear battery is likely at 40% of its original capacity. If its an old enough one when they were still built correctly, (AKA the original battery 15 years back) they can be revived by topping up till the white glass matting swells up and covers the lead plates - then 6 month down the road with regularly charging it will recover to about 85% capacity - which is more than most deliberately badly made brand new ones give after 12 months of use

 

The load test on the 100 Ah battery failed, looks like I will have to get deeper into the recycling process to revive it till the new battery turns up. Will update outcome.

 

interesting, have you done this with a sealed battery ie the maintenance free ones, if so pl share the process

 

Here is my VIN: WDD2210712A025336, I have gone through the typical free internet based sights that give the VIN decoder Data Card. If you have access to some portal that gives more specific data pl share with me thanks in advance.

 

the is no such thing as a maintenance free battery - just a lie by the makers to help you damage the planet and increase their profits - they all have a breather and the moisture escapes till they go progressively downhill - they are making it increasingly difficult to check and or top up the level of all designs (of course use your brain, and never fiddle with a lithium thing that are on a few exotic vehicles or as an unsuitable aftermarket lightweight replacement !!!)

the Merc OEM AGM one on my father's car, new 4 years ago (but fading two years ago when I forced open the lids...) had three of the six stupid almost impossible to unscrew lids BONDED in place for added failure - so you self destruct things getting them out - to find it BONE dry with bare plates showing - I topped it up but one cell fizzed up - but its still in there working

my same spec yuasa 5 year guarantee AGM battery was replaced (under warranty at 4.5 years as was dying), its replacement at 2 years in was grim, so I opened it up to find this brands lids came out quite easily, where I found it was bone dry with bare plates showing, I topped it up and no fizzed cells

on two diff motorbikes an Odyssey AGM died over night at 4 years old, I topped it up as was totally dry and 6 years on still works - except 2 years ago topped it up and again very dry, but this time 2 cells fizz up and puked their guts but whilst they don't like to stay as damp as they should, its still going... Whereas on a Motobatt one the bonded on lid cracks off to reveal the 6 rubber bungs on each cell top, just like the Odyssey battery, but this fizzed up and won't respond

My OEM one now 17 years old sit in the garage and (having been topped up) can push out 12v after being uncharged for 3 years and sat cold through three winters... I used it as a slave for pumping up bike tyres and for a work light

At your risk - all one can try is to get the lids off and top it up - but it seems they did something to make later ones react badly and or you waited too long to try and do the maintenance they don't want you to do...

.

 

Merc make this easy - look on youtube for the secret cluster menu - and toggle it to the volt meter - and see what it says - but note: batteries that are not working as they should will not allow an alternator to fully understand how to do its part.

 

I agree I realised once I dove deep to revive some of my dead "Flooded" Lead Acid Batteries that the difference was probably only that sealed evaporate slowly but according to the manufacturers desired time, just in time to do it beyond its warranty. So logically if one could get the sealed top opened or make it to the cells without damaging it, one could possibly revive it by immersing the plates in the required mixture. Pl do comment on this theory.

"fizz up" please explain what that looks like.
"almost impossible to unscrew lids BONDED" How did you manage to open these?
"all one can try is to get the lids off and top it up" When you say top up are you also suggesting we add the Sulphuric Acid or just the Distilled Water?