AGM or Lead Acid?

[steveskeggy]

OK, my car is a 2003 S55 AMG W220.
It does not have start/stop, so it has just the one battery in the boot.
It eats batteries at differing rates, the drain is OK, it has just always done it.
I am used to it eating a battery every 18 months, but every now and again, I will get one that only lasts six months.
I dont use the car every day, and I think this may have something to do with it.
But I dont need advice on what may be causing any drain or how long a battery should last, I know I would be as well sorting out the cause first, blah blah.
What I want to know is, On the W220 site, it says that Mercedes Benz recommend an AGM for the W220.
However, I keep coming up on conflicting statements, saying that to use an AGM, the car would have to have extra equipment (Dont know what) and it would have to go on STAR to tell it that the Battery is AGM.
I also read that if an AGM battery goes under 10v it is basically stuffed, not much use in my circumstances.
If it is a faff around, I will stick with Lead/Acid, but as AGM batteries are supposed to last longer, it may be better if I can.

 

[whitenemesis]

Any info regarding the type of battery in your owner's handbook?

 

[grober]

W220 S-Class Encyclopedia

w220.wiki

Battery - W220 S-Class Encyclopedia

w220.wiki

Alternator - W220 S-Class Encyclopedia

w220.wiki

 

[grober]

You may have a parasitic drain or alternator problem [ under or overcharging] Get it checked at a good auto electrical service centre --- if using the car at irregular intervals it may be worth investing in a trickle charger - C-TEK are good

 

[Bobby Dazzler]

Which have you been fitting so far, AGM or regular lead acid? Have you tried using an battery charger to maintain and recondition the batteries.

I don’t think fitting an AGM will enable it to last notably longer than a regular lead acid - AGM is a type of lead acid battery - whatever is killing it will kill an AGM too.

Might be worth asking the parts counter at your local Mercedes-Benz dealer to quote for the battery and to advise whether it’s lead acid or AGM.

 

[AMGeed]

Might be worth asking the parts counter at your local Mercedes-Benz dealer to quote for the battery and to advise whether it’s lead acid or AGM.

As above, the main dealer can supply the correct battery from the Vin/Reg#

Going through batteries at the rate your car does points to a constant battery drain which a good indy may well be able to pinpoint with a Star session. Got to be cheaper than keep throwing batteries at it.

 

[pmcgsmurf]

VIN # would confirm what was fitted from factory.

 

[190]

What I want to know is, On the W220 site, it says that Mercedes Benz recommend an AGM for the W220.
However, I keep coming up on conflicting statements, saying that to use an AGM, the car would have to have extra equipment (Dont know what) and it would have to go on STAR to tell it that the Battery is AGM.
I also read that if an AGM battery goes under 10v it is basically stuffed, not much use in my circumstances.
If it is a faff around, I will stick with Lead/Acid, but as AGM batteries are supposed to last longer, it may be better if I can.

I see no problem fitting an AGM. The only difference with charging an AGM is a slightly higher voltage than a normal battery which will be why star needs to be used but it's not the end of the world if it's charged at the normal voltage. It will still work.

Whether there would be any benefit in fitting an AGM is another question. AGM's have better cranking power due to lower internal resistance which also reduces the self discharge rate in long term storage. But if I understand you the problem is the battery goes flat often enough to severely shorten it's life. An AGM will still suffer under that regime but may be marginally better at coping with severe discharge although I doubt the improvement will justify a substantial extra cost. The thing about being stuffed at 10V is because that represents a fully discharged battery which when it occurs often enough is just as bad for a standard battery as it is for an AGM.

So far I have observed your request not to advise on the underlying cause of premature battery failure but I will make one observation. We are all assuming the battery is failing due to being deeply discharged too often but if in fact the cars alternator is severely overcharging your batteries then an AGM will fair worse than a normal battery.

 

[mioba]

Forget what it says on the internet for W220,
You need to be vin specific.

AGM batteries have deeper discharge and charging cycles and the car has the correct equipment (electrical) to charge such a battery. One should not think AGM battery wohoooo lets fit it in my car.

You need to fit the battery your car was built for. A trip to the local MB dealers is in order.

 

[steveskeggy]

whitenemesis: its a 2003 handbook, so not much use on this.​

grober: yes, this is why I am asking, and there is nothing wrong with the alternator. I also stated that I didnt need answers about the cause.​

Bobby Dazzler: Lead acid, my local main dealer is about as much use as a chocolate teapot as far as W220`s are concerned, I read that AGM last longer than lead acid, which is why I am asking about them.​

AMGeed and pmcgsmurf as above, its a w220174.​

190: Thanks, like all the other answers, I dont need to discuss what the cause is..​

mioba: I didnt think "One should not think AGM battery wohoooo lets fit it in my car.", I am doing research first, the car was obviously built for lead acid, AGM were around in 2003, but few and far between were fitted to standard cars.​

I am giving up on this, I will be buying a Bosch lead acid, because they seem to be the ones that suit my car best.​

​

 

[whitenemesis]

Most battery manufacturers/suppliers give a warranty on their batteries. Have you ever tried to claim?

 

[pmcgsmurf]

pmcgsmurf as above, its a w220174.​

But you can't search based upon the car type, does not tell 100% what was fitted, as I said your VIN # is your friend.

I am giving up on this, I will be buying a Bosch lead acid, because they seem to be the ones that suit my car best.​

​

No need, just post your VIN and the question is answered.
Everything else is guesswork.

 

[grober]

Compare Different Vehicle Battery Technologies

Compare the differences across battery technologies including standard flooded, enhanced flooded and absorbent glass mat.

www.autobatteries.com

 

[Deleted member 126251]

Forget what it says on the internet for W220,
You need to be vin specific.

AGM batteries have deeper discharge and charging cycles and the car has the correct equipment (electrical) to charge such a battery. One should not think AGM battery wohoooo lets fit it in my car.

You need to fit the battery your car was built for. A trip to the local MB dealers is in order.

^^^^^^^^^^^^^^^^^^^^^^^^^
What he says. AGM need a different charging regime.

 

[MrGreedy]

 

[Jibbajabba]

Cars with Stop / Start almost always have AGM ... So if you don't have Start / Stop I would bet you got lead acid ... And yes, AGM needs different charging or you trash em ...

 

[whitenemesis]

AGM batteries are also specified if the battery is located within the passenger cabin