Auxiliary Battery, AGM
Thread Starter
MBWorld Fanatic!
Joined: Nov 2004
Posts: 1,121
Likes: 86
From: West Plam Beach, FL
'16 S550 Coupe, '11 Lexus LS460, '02 CL500 (SOLD)
Auxiliary Battery, AGM
In swapping out my aux. battery located in the trunk of my '16 S550 coupe, there is a venting tube for it. This is an AGM battery, p/n 000-982-96-08, so why did MB vent it? It's a PITA to hook up due to limited space so I didn't do it. Now I'm having seconds thoughts.
Super Member
Joined: Jul 2007
Posts: 742
Likes: 228
From: Santa Barbara, CA
S550C4, Porsche Cayenne
In swapping out my aux. battery located in the trunk of my '16 S550 coupe, there is a venting tube for it. This is an AGM battery, p/n 000-982-96-08, so why did MB vent it? It's a PITA to hook up due to limited space so I didn't do it. Now I'm having seconds thoughts.
Thread Starter
MBWorld Fanatic!
Joined: Nov 2004
Posts: 1,121
Likes: 86
From: West Plam Beach, FL
'16 S550 Coupe, '11 Lexus LS460, '02 CL500 (SOLD)
Thanks. Where can I find the documentation you have. Funny, I've owned a few Vettes, 70's & early '80's, and the battery was in the back storage area inside the car. No venting on those.
Last edited by Jud Chapin; Dec 23, 2020 at 01:05 PM.
Super Member
Joined: Jul 2007
Posts: 742
Likes: 228
From: Santa Barbara, CA
S550C4, Porsche Cayenne
Super Member
Joined: Jul 2007
Posts: 742
Likes: 228
From: Santa Barbara, CA
S550C4, Porsche Cayenne
Thread Starter
MBWorld Fanatic!
Joined: Nov 2004
Posts: 1,121
Likes: 86
From: West Plam Beach, FL
'16 S550 Coupe, '11 Lexus LS460, '02 CL500 (SOLD)
Thread Starter
MBWorld Fanatic!
Joined: Nov 2004
Posts: 1,121
Likes: 86
From: West Plam Beach, FL
'16 S550 Coupe, '11 Lexus LS460, '02 CL500 (SOLD)
Well, it's been eating at me that I didn't rehook up the vent so I decided to have another go at it as I'd rather be safe than sorry. Amazing what a snap this job is of swapping out the aux. battery once you've done it. Anyway, I got access to the battery again and placed the plastic angled vent part with the tube connected into the battery. Then with the battery in place, I sprayed WD-40 on the tube and it slipped right in to the car's vent hole in the trunk. Without lubricant, it's tough getting the vent tube where you want it due to limited space. The whole job took about 45 minutes as opposed to a couple of hours the first go around. There's a lot of confusing info out there on doing this job including MB's WIS. If my aux. battery were to need replacment again, I'm sure I could do the job in 1/2 hour or so. Keep in mind this is for the S550 coupe but I imagine the S550 sedan is basically the same.
Of interest is what this battery is called. I see where just MB has several names for it including auxiliary, starter, and additional (WIS).
Of interest is what this battery is called. I see where just MB has several names for it including auxiliary, starter, and additional (WIS).
Trending Topics
Super Member
Joined: Jul 2007
Posts: 742
Likes: 228
From: Santa Barbara, CA
S550C4, Porsche Cayenne
Well, it's been eating at me that I didn't rehook up the vent so I decided to have another go at it as I'd rather be safe than sorry. Amazing what a snap this job is of swapping out the aux. battery once you've done it. Anyway, I got access to the battery again and placed the plastic angled vent part with the tube connected into the battery. Then with the battery in place, I sprayed WD-40 on the tube and it slipped right in to the car's vent hole in the trunk. Without lubricant, it's tough getting the vent tube where you want it due to limited space. The whole job took about 45 minutes as opposed to a couple of hours the first go around. There's a lot of confusing info out there on doing this job including MB's WIS. If my aux. battery were to need replacment again, I'm sure I could do the job in 1/2 hour or so. Keep in mind this is for the S550 coupe but I imagine the S550 sedan is basically the same.
Of interest is what this battery is called. I see where just MB has several names for it including auxiliary, starter, and additional (WIS).
Of interest is what this battery is called. I see where just MB has several names for it including auxiliary, starter, and additional (WIS).
MB World Stories
The Best of Mercedes & AMG
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Flawlessly Restored Mercedes 190E Evo II Heads to Auction
Verdad Gallardo
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know
Verdad Gallardo
Mercedes EQS Gets A Major Update: Everything You Need to Know
Verdad Gallardo
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve
Verdad Gallardo
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping
Verdad Gallardo
10 Most Reliable Mercedes-Benz Models You Can Buy Used
Verdad Gallardo
Out Of Control!!
Joined: Jul 2003
Posts: 15,901
Likes: 4,630
From: North Scottsdale, AZ
'71 Pinto
Last edited by konigstiger; Dec 29, 2020 at 02:45 PM.
Thread Starter
MBWorld Fanatic!
Joined: Nov 2004
Posts: 1,121
Likes: 86
From: West Plam Beach, FL
'16 S550 Coupe, '11 Lexus LS460, '02 CL500 (SOLD)
Thanks...I have WIS and have used it for years but unfortunately have had my ups and downs with it. I find it not particularly user friendly. In the case with the aux battery, it states to remove the right trunk panel for access and refers you to a section on how to accomplish this. Unfortunately, these instructions only show how to remove all trunk panels with no explaination regarding removal of just the right. Further, the most important step is missing showing how to remove the chrome trim at the opening of the trunk, or at least I couldn't find it.
Without first removing this piece, no panels can be removed. Actually, to remove the right panel, as I discovered on my own, just the chrome piece and the 2 bottom panels need removal which is not mentioned. If memory serves, an MB tech told me that they take WIS classes before using it.
Out of curiosity, have you done this job using WIS instructions only?
Without first removing this piece, no panels can be removed. Actually, to remove the right panel, as I discovered on my own, just the chrome piece and the 2 bottom panels need removal which is not mentioned. If memory serves, an MB tech told me that they take WIS classes before using it.
Out of curiosity, have you done this job using WIS instructions only?
Last edited by Jud Chapin; Dec 29, 2020 at 02:38 PM.
Thread Starter
MBWorld Fanatic!
Joined: Nov 2004
Posts: 1,121
Likes: 86
From: West Plam Beach, FL
'16 S550 Coupe, '11 Lexus LS460, '02 CL500 (SOLD)
For those wishing to remove the chrome piece, the obvious first step is to remove the 2 retaining clips located on the black section of the trim facing the inside of the trunk. A flat bladed screwdriver works well here.
The final and much less obvious step is to pull straight up on the piece. It is held in place by 4 other retaining clips not visible from the outside. For access to the right panel behind which the aux battery is located, simply remove the 2 lower panels on the floor of the trunk.
The final and much less obvious step is to pull straight up on the piece. It is held in place by 4 other retaining clips not visible from the outside. For access to the right panel behind which the aux battery is located, simply remove the 2 lower panels on the floor of the trunk.
Last edited by Jud Chapin; Dec 29, 2020 at 03:21 PM.
