IAATM

I have a 2012 S550 (W221) with 50k miles on it and still the original OEM MB battery.

The guys at Sears put their meter on it and told me that while it's low on the CCA's, it's within spec and so doesn't "need" to be replaced today.

Nevertheless, I'm toying with the idea of just paying the $175 now for a DieHard AGM, since a) it'll have to be replaced at some point anyway, and b) I'd rather replace it on my own terms, as opposed to the time and place of the battery's own choosing.

I'm curious how long we (as a community) should really expect the OEM batteries to last on these cars when driven in the heat of southern CA and NV?

Your thoughts and personal experiences are warmly welcomed!

1bad540

I changed mine about 2 mos ago on my 2010 the battery was done in 2013 and cranked slowly 1 to many times, went to benz dealer close by and pretty sure i paid over 300. Installed myself. Its cheap insurance.

steveb9771

OEM batteries have an extremely long life. I have a 2007 CL550 delivered November 2006 which has two batteries. Engine starter battery failed after 7 years. The second consumer battery located in the trunk is now almost 11 years old with no problems. I live in Southern California. OEM batteries are expensive, but are well worth it based on their longevity. The Sears battery warranty may become worthless if the prediction that Sears may go bankrupt occurs. They hare already sold off some of their crown jewels. Craftsman tool brand is now owned by Stanley Black and Decker. Kenmore appliances are now also sold by Amazon.

Welwynnick

In general I wouldn't replace something for the sake of it, other than consumables.

Batteries last a long time if you keep them charged up at all times.

12.4V is the magic number, though you may not see that when you open the doors to check, as lots of things switch on and drag the voltage down.

Edit: Agree with others that they don't last long in the heat, though.

Nick

dlafever

I think it depends on how long it has been in service and where you live. Here in the Sonoran Desert a battery can give up the ghost without warning. I've had it happen several times, my favorite being when I drove to the auto parts store to drop off used oil and upon returning to my car found the battery to be DEAD. Just stone cold out. Terminals clean, alternator charging as should be, heat kills them. At least I was somewhere that I could buy a new battery and just walk the core back inside the store.

The Thomas J

My 08' E class had the original battery until May of 2016 when it died without warning. I'm not sure how old the battery in my S class is. I was thinking of changing it for the sake of changing it.

Donnymac

I have the same car as you. OEM battery was showing its age on starts. Last month, I dropped in an Interstate. Good as new now.

So, 5 year 90K mi Texas run on an OEM battery. Below freezing in the winter and +100 in the summer. Not bad for an OEM battery.

KNBS550

If you don't mind the hassle of waiting for MB roadside service after the starter battery dies, change the battery.

The Thomas J

I changed the battery on my car today. It still had the Mercedes stamp on it so I'm not sure if it was the original or dealer replaced. In any event, I had noticed the car turning over a little slower than usual. Yesterday I was sitting in the car with the engine off and accessories on for about 10 minutes and the car gave me a hard time starting. So, off to Autozone I went. It took me about 45 minutes to install. Pretty straightforward. I had to reprogram my auto up on my windows.

llcd

I learned my lesson on not being pro active in changing my car battery on any car I've owned. The risk of not knowing when the battery might die to me is not worth the risk.

M-a-x-G

Batteries are designed to fail after a certain time; I know, because I worked in R&D, where batteries were designed to fail after a predetermined time frame.
I recently bought a 2011 S350, and when I realised on the second day (a Saturday) that it was the original battery, I looked for a replacement -- which I planned to pick up the following Monday. The car used to 'live' at the coast, with temperatures not falling below 16 degrees C (61F). I live 200m above sea level, and that night had 3 deg C (37F). When I tried to start the car on Sunday, it did not start. Battery dead.
The issue with today's batteries is that they die almost instantly. I have no desire to get stuck based on a predictable failure, hence, will pro-actively replace any car battery older than four years; which is way cheaper than the cost of towing and workshop replacement.

wilderS65

Ive seen Batteries go bad on brand new MErcedes in 18 months. Some last 7 years. Just because it cranks doesnt mean the battery
is good!!!