Thats what I meant, yes There are different types of batteries, but in the same type, there's no difference.

As for that vent, mines under the rear seat and has none, so dont know about that one.

 

^^^ + 1 Under the rear seat
Mike,
mine has indeed a "venting" tube, but it IS NOT DESIGNED to go nowhere near the outside of the car as its length just reaches the bottom of the battery. I suspect the "Audi approved batteries" motto is probably just one of the many other commercial ploys... What "legal" and "safety" reasons are you talking about? Where's the "safety" in venting the fumes inside? (I'm talking about the C4)
I could understand the "legal" reason (People not buying THEIR overexpensive batteries would not have a "case" in the event they have a problem and the battery is not "Audi approved"). However, the "'safety"' reason leaves something to be desired... as the potential fumes are still "vented" in the cabin, so...
I would say to anyone:
use whatever battery you feel like, provided it has the apropriate voltage + cranking amperage.

 

The vent is over kill.. Batteries produce Hydrogne gas in small quantities and it disapates very quickly so there is no danger. My daughter's VW passat (Audi) had the battery under the cowl in the engine compartment and the VW dealer scared her by pronouncing that it was not safe because the little tube was not connected.

I had a calm discussion with him and he insisted that it was unsafe until I explained that I work with high temperature furnaces that have high purity hydrogen atmospheres. I explained to him that 5% hydrogen in air is considered safe by the NFPA and IBM did a study showing that 8-9% would barely ignite if there was a continuous ignition source. The little bit of hydrogen that might escape from a battery is not an issue unless it get trapped and accumulates over a long time period.

BTW they apologized and gave her a free oil change --

 

@ NH_USA -- Pwned their faces.

 

A stock battery vent tube goes down through the bottom of the plenum into the steering rack area. If yours does not, yours has been modified (i.e. broken). No big deal as others have pointed out.

Bob

 

We're talking about different cars, Bob... if that was intended for me.
You're talking about C5s (battery under the cowl), while I specifically pointed out that I have the battery under the rear seat, same as Jim's 1996 car.
Nothing was modified. Just as I said, the tube is worthless as there's no hole designed for "venting the battery under the car", as Mike was talking about.
I was just questioning the "legal" and "safety" reasons he mentioned....that's all.

 

If there is a malfunction in the electrical system there is the possibility of a release of acid from the battery, both fumes and liquid. Both a short in a larger non-fuse protected wire or a loss of regulation of the charging system could cause this. Unlikely... but we are talking about Audi's!

If the battery was in the normal location, in the engine compartment, it may cause damage but should not create a hazard to the passengers. But it is not in the engine compartment, it is right next to the outside air intake for the air conditioner. Technically the battery is in the passenger compartment.

With today's "sue happy" public, the Audi lawyers will not allow the company to open themselves up for law suits, even for relatively unlikely problems. Especially when the main cost "to the company" is a higher cost of a replacement part. Last time I looked even the battery company's listings only list a few batteries for our application.

My recommendation, (but it is up to you if you use it -- Legal disclaimer) is to use some kind of a sealed battery. I chose an Optima (not listed for Audi's) due to my past experience with them. It does have a "normally closed" vent so it isn't totally sealed.

For the "older" cars: VAG has been putting batteries under the rear seat for a long time. My 1957 VW Bug and 1978 Audi 5000 both had batteries under the rear seat. The Bug used a "normal" battery and rusted the bottom of the battery box. The 5000 had a tube vented battery that drained into a plastic cup that drained outside the car. (If I remember correctly, I last saw that car somewhere in the late 80's.)

My point is that what is done in the past, for "safety" and "legal" reasons, may not be what is done now or in the future.

 

Well, exactly. I foresaw the legal aspect, but I had a little "gripe" with the safety reason.
The C4s (at leats mine, and I doubt there's an anomaly among them) don't have the plastic cup you're talking about. Maybe the "safety" issue became one when they redesigned to the C5.
Anyway, when you refer to a "sealed" battery, I would assume you refer to what they call a "maintenance free" battery. Tks for the gracious opinion.

 

ppgoal: If you were spending $160 @ Autozone on your battery, why didn't you just go to the dealer and get the specifically recommended OEM one for less? lol The parts depo guys at the dealership I go to gives me 20% off all parts, all the time. However, when I replaced my battery, MSRP was $150, dealership paid $120 invoice, so Bruce hooked me up and gave it to me for $130, only making $10 on it (last 1 they had too *snickers*) He even showed me on the computer (as he always does) the real invoice of his order statement and yes, he truly did pay $120 (just in case someone thinks he was just blowin' smoke). I just want to know, esp pertaining to our OEM batts, c'mon guys - it is 2010 and you're telling me you can't invent a battery that doesn't weight 60 lbs? LOL

 

Um... I've got a bridge to sell...