[_S3C_]

Does the SL's have battery vent tube that is venting the battery gas out of the trunk ? ( or the side square plastic flaps (the one right next to the battery negative terminal) are "used" for venting purpose) !
For some reason I don't see any vent tube or any SMALL size plugs for the tube in my car ...

Thanks in advance

 

[RKH]

The R129 does not use vent tube. The battery compartment is vented via those "plastic flaps" (or as Aam used to called them rubber slugs).

 

[Lancair]

If your battery has a vent tube:
Just remove the battery tray. On the bottom you'll find a large rubber plug with three small holes. Put a 2" piece of brass tubing (approx. 6mm diameter) through one of these holes and connect it to the battery with some clear PVC hose and you have a far better venting than stock.

The battery compartment is vented via those "plastic flaps" (or as Aam used to called them rubber slugs).

Battery venting is not the principal task for those plastic flaps, it's "depressurization" of the interior if you close the trunk lid, doors with windows up and hardtop on. If not in place, you would have to slam the trunk lid/doors with brute force due to overpressure. Ok, on newer cars the windows lower approx 1/2" during door operation but this is sometimes not sufficient. The real reason for this is a special rubber seal design on the hard-/soft-top and not de-aeration.

If you drive with open top, and leave the trunk closed, those rubber flaps remain closed and do not vent anything (IMHO). Same if you store the car connected to a battery conditioner.

My car came with a "fully sealed" 5 year old DieHard Battery without vent tube which doesn't mean there's no gas production. Any lead battery (even GEL and AGM) include a pressure valve releasing excessive gas from time to time.

I also found some strange discoloration over the whole trunk floor mat (Java / bright color) that steadily went darker towards the battery location, the side trim was unaffected. For me a clear indication for battery fumes. Of course you won't see anything on black trunk mats….

Recently replaced this battery with a new one (also "fully sealed") that came with a vent tube and connected it as described above (see pic).

 

[_S3C_]

RKH and Lancair, thanks for the replay & info, I did TEMPORARY installed tubing that is venting out true that very same plastic flap (as my car is stored for now and I charge the battery from time to time with battery charger (2 hrs every 15 or so days)), hope the gasses from that vent tube will not do any harm on the paint or metal when escaping as the end of the tube sticks out between (behind) the bumper and the frame .....
Lancair after some another month will do the way you did it as it does sound professional and not that hard to install !
I'm a bit puzzled to see that vent tube to be missing on the SL's, when every other MB model does have one ever since ..... wonder if that is only on the '98 and UP Chry$lering$$$ Era ......

THX


PS: btw Lancair did you install that 12V sockets by your self or the SL600's comes with it as standard ?
-(after all it is nearly $30k difference in the price between the models and my SL500 does not have it)!



- any other hidden wonders besides the "normally missing" LIGHT under the eng. hood, but that's proly another subject lol ?

 

[RKH]

Good point Lancair, as the R129 did not come with any vent tubes, so I thought it was vented other way by design and doesn't need one.

 

[Lancair]

Installation is really easy. However, there's not much room left for the PVC tube (between the wheel housing and battery tray) but it went in without squeezing.

I've attached some more pics. The first one shows shape and location of the plug. The outer end looks like a tube, therefore no "danger" for the underbody, even if the batt spills liquid acid. The second pic shows the discolored trunk mat. Really looks like the battery was the culprit. It can't be heat from the exhaust because the muffler is on the opposite side which still looks like new.

Yes, I've installed the 12V socket as a "permanent solution" for my MB/CTEK battery charger/conditioner. "Borrowed" from an SL (R230) the p/n is: A 230 820 01 51 (~US$10). It connects directly to the batt poles with an additional 10amp fuse in the +line.

Lance

 

[_S3C_]

Lance, great info & pix, Thanks for sharing! - For sure it is one of my next mod, for when the weather get better! (btw somehow that PN is not coming up under the MB parts search, but I got the idea (on BM-X5's they have the same plugs ....) and def. it is a must have mod for me to).

Happy BennZZZing

PS: .... yeah ~ agree that discoloration happened from the escaping battery gasses !

 

[Lancair]

Glad it helped .

(btw somehow that PN is not coming up under the MB parts search, but I got the idea (on BM-X5's they have the same plugs ....).

Hmm, strange . Got it straight out of MB EPC net. The very same plug/pn was used in the whole MB car range (SL, CLS E, SLK, ML, etc.) and it still exists (check here).
Hope the BMW plug will work in an SL....

Good luck!
Lance

 

[lynns]

btw somehow that PN is not coming up under the MB parts search

In the US you can always leave the 'A' off of the p/n and it's important that you get rid of any blank spaces between the numbers.

p/n 2308200151 Power outlet 2006-2009 $24.08 w/ S&H at Parts.com

 

[500SL4Me]

I just ordered that, does it come with the wires to conenct to the battery. I am actually doign it to plug in my CS2000 scanner rather than using alligator clips on Battery.

 

[lynns]

I just ordered that, does it come with the wires to conenct to the battery. I am actually doign it to plug in my CS2000 scanner rather than using alligator clips on Battery.

I would probably pay the small extra $'s and buy this part from my local MB Dealer after seeing the actual part.

 

[FahadsC320]

For W203

Where does the battery vent tube plug in the body? I understand one end of the tube is in the 90 degree elbow which is in the battery. The other end of the tube plugs in where? Is there is hole where the tube plugs into? Would the hole be under the battery? Does any one have a diagram or a picture which can help me?

My goal is to properly vent out the battery because the cabin filter sit on top of the battery. IF gasses are being released from the battery vent, I don't want it being sucked into the cabin when I turn on the air or heater.

 

[Pete S]

Better to ask this in the W203 forum, you will have people with more knowledge of that chassis there.

W203 C-Class - Mercedes-Benz Forum

 

[cliffyk]

In the Fall of 2000 MB started using VRLA AGM¹ (Valve Regulated Lead Acid Abosrbed Glass Mat) batteries in all models (the r129 got them in '98). AGM batteries do not need to be vented; and what looks like a vent nipple is a blowout port that ruptures if the battery's internal pressure rise to a catastrophic level.

Miata's used trunk mounted AGM batteries since their introduction and on the early model the blowout port did have a "vent" tube to carry the nasty stuff out of the trunk. Thing is that never happened--in fact I have never seen a AGM battery fail in that manner--and in '94 the "vent" tube was eliminated, causing the same concern in the Miata camp as expressed by the OP in this thread...

--------------------------------------------------
¹ - Note that the Distinguishing features section at the foot of the document states "No stop plugs", "No externally vented stop plugs".

The information note re: replacing the battery refers to replacing the AGM battery with a non-AGM unit. In that situation the vent tube should be connected and stop plugs inserted.