Suppaa Mario

Well according to their fitting key this does not fit the cls 550 2014, w218. Or am I blind.

cls5504matic

You're right. The CLS 550 battery is part number out of my car is a211 541 00 01 but the battery listed is for the CLS63 I think the difference is the FCP listed battery is a bit bigger capacity and perhaps a bit cheaper (than I could find the a211 541 00 01 battery for ymmv).

Fitment wise I believe they are the same as FCP lists the CLS63 as fitting (so the vent cable should work), it has the threaded terminals which is helpful, and I believe they are both classified as AUX14-1.

Suppaa Mario

I see, did you use that one on your cls? And your cls is a W218 correct.

cls5504matic

2014 CLS 550 4matic USA spec C218/W218. I went with a duralast platinum which I believe is the same as the odyssey battery. But honestly I would go OEM fitment for this. It was a lot more effort than the savings was worth. I had to convert the vent tube down to a smaller size. As well as account for a different location. This battery is a AUX14 fitment battery group. So not 100% certain myself but I would say something like a great likelihood the battery fits. If I am certain in the future I'll update with a picture.

Suppaa Mario

I see, I was able to get it for 145$ oem from my dealership.

Tbbt CLS

Just making sure you're talking about the auxiliary battery, right? This is basically an AGM motorcycle battery that can be purchased for much less elsewhere. Marv

Suppaa Mario

Correct, I got it oem from the dealership for 145 bucks since I did not want to mess with any fitment issues as the user above mentioned. Front battery is in the garage waiting to get installed. Followed the advice to go get an AGM H8 from Autozone. Batteries are heavy 😂

Tbbt CLS

HaHa, yes batteries are heavy! The old joke in the industry was "how can we get the lead out" for cost savings. Batteries are primarily lead. More lead equals more CCA power. Marv

Roop94

My battery just went out and ordered AGM battery. I was about to order the regular one, until I did some research on it. AGM runs a bit expensive than regular, which is why I was like let's save some $ haha. I actually ordered it online and having it delivered hopefully tomorrow or on Saturday.

And as I understand, we have to sync the windows, locks, and the sunroof once the new battery is installed, right?

Suppaa Mario

Not 100% sure. I have the work order and instructions it does not indicate that needs to be done.
So I went ahead and removed the main battery cover today in anticipation to change the main battery, come to find out, batter was changed prior to me purchasing the vehicle 2/17. So the battery is a little over 3 years old. Car is off and battery is at 12.40volts. When the car is on and its under load. All accessories on. It's 14.79volts. Can somone confirm that this is a healthy battery so I can go ahead and return the new AGM I bought?

Roop94

Hmmm, interesting. I have a link saved on my phone where it says to do all that lol but I haven't checked the manual yet. Maybe I should look there first.

Tbbt CLS

There is a handy tool available that uses a 9V battery, you plug it into the cigarette lighter and it saves your presets. Should be available at most Parts Stores for about $9.

bsaz

FYI Have a CLS550 with the two batteries, main & aux for auto start.. The Aux. is in the trunk on the 2014 CLS, my comment is that the Aux battery on this car is NOT connected to the circuit, and won't charge, if you use an external charger on the main battery. Discovered that from the MB tech, eventually the auto-start battery died, replaced once under warranty, died second time, ignored the aux battery msg, auto start doesn't work but fine with me, (its a PIA anyway), all is well, message stopped showing up car runs fine.
P.S. Batteries in Tucson only last about 3 yrs 4 if you are lucky! I keep all the cars on charges most of the time when they are parked...

Getting 2021 GLC 43 in December....

Dblok1113

this is not the first time I heard this, but i changed my main battery no issues whatsoever with presets or anything. I literally disconnected old battery and installed new agm battery I got for 200 at auto zone I was quoted 450 something as well from an Indy mb shop decided it was simple enough. I have a 2014 rwd not sure if that matters, but had no issues

Roop94

Same. I replaced the battery and no presets disappeared. Everything is just as it was before. Although there is one thing that changed with battery replacement, but I can't remember what that was haha.

bsaz

I am in the process of replacing my primary battery, got the new battery, a Champion PCBH8-900CHAGM at Pep Boys for $171 w /tax. It was 25% off when ordered on-line and has 900 CCA. Looks identical to the MB battery. Not as gutsy as you folks, I'm going to do the back-up codes via the OBDII connection ($12 cable fm Amazon) and a spare battery. Just a thought as I'm about to do this, a MB mech.once told me the aux. battery is not charging when the car is connected to a trickle charger, so I'm guessing the in-trunk aux. battery will also not help preserve the presets etc. when removing the primary?? Any thoughts why the 12V battery in the trunk won't/doesn't provide the necessary back-up power to preserve the presets and other computer functions?? (2014 CLS550)
Update: did the swap, all is well, everything is back to normal, my eco. auto stop/start might have come back,(not that I want it!), will see when I hit my first stop light. Used the above mentioned pre-set saver, took about a whole 10 minutes, but then I move a little slow! Thank for all the great info. on this thread.

Roop94

Oh, my front passenger seat doesn't roll forward as much as it should since the battery replacement. The back does move back and forth just right, though. Wonder what should I do...?
The presets are all there.

therocket

I used when I changed my main battery with an OEM one last week. A MB mechanic highly recommended using a memory saver for a variety of reasons.

Dblok1113

wish I would of known before I changed, I would of spent the 20 bucks or whatever it is. I don’t notice any difference in anything since the replacement though but I know for the future now. I adjust my chair every time I drive so I don’t use the presets for my chair. It’s my only complaint I wish I had more head room, sometimes wear a hat and it hits the ceiling but I’m always adjusting my chair. So I don’t know if those presets were ever changed.

bsaz

FYI weighed my primary bat. when swapping, new Champion Battery was 52 pounds.

Tbbt CLS

Bsaz, did you happen to weigh both batteries? Just wondering. Marv