Quick Battery Question

[John B.]

Battery failed in our 95 525i Touring last night so I'm going with the Autozone 49-DL. The Interstate battery that was in there had no vent tube like the one in my 90 535i does & there was no sign of a factory venting set up. Did they do away with this on the later cars?

[KenB]

I just put in a Duralast a couple months ago. Look for a hole that the vent hose goes thru in the floor centered behind the battery.(towards the rear of the car)

[John B.]

I just checked & I found where the hole is. On my car its filled with factory sealant & coated with the original paint so it's obvious no battery has ever been vented in this car. Maybe by late 95 production they figured modern sealed batteries didn't require it??

[ryan roopnarine]

then pop it out, and plug it in. i'm thinking that maybe that was supposed to be something that the dealer or unloading point did, as you wouldn't want the "ocean spray" to come in the car.

[KenB]

My car had a BMW vented battery but the tube was not hooked up, the tube didn't fit the vent. The Duralast came with everything needed to vent, including an adapter to connect the battery vent to the tube.

When I bought mine, they had a deal that if you bought a little package with felt terminal protectors and dielectric grease, for $1.99, they gave you 10% off the price of the battery at AutoZone...It was around $65 with tax IIRC.

[John B.]

Not to be argumentative but why is the vent set up necessary with a sealed battery? Obviously my car has gone 11 years & 137k without it and there are no signs of corrosion around the battery.

[ryan roopnarine]

Not to be argumentative but why is the vent set up necessary with a sealed battery? Obviously my car has gone 11 years & 137k without it and there are no signs of corrosion around the battery.

it isn't for corrosion, its more for explosion abatement. if you spend any time around an unenclosed battery (by that i mean one that you can see all of the time), you'll see that vibration, movement, queer electrical loads WILL cause it to spark at the terminals, even if only once in a blue moon. the same is true with lightswitches, occasionally, you can observe a spark come off of a household light switch. unless you are dealing with a truly sealed gel battery (like an optima) that you can mount upside down and such, any other choice will not be truly sealed. even maintenence free batteries have provisions for removing the venting caps with screwdrivers and such. if it is a car battery, and it isn't a gel type, it vents explosive h2 gas to the atmosphere under electrolysis (hence bmw's insistence for a vent kit). if the car was new, maybe then i'd say that one's risk is low, but considering how connections corrode, get worse, &c. as the car gets older, i certainly wouldn't want that thing under my back seat without a vent on it. car batteries explode underhood every day--well maybe not every day, but i've certainly seen one--and the ones underhood don't even NEED vent kits.

[Ross]

My understanding is that the term sealed is a misnomer. Batteries supposedly never requiring water came to be referred to as sealed.

[Elekta]

I bought the sears version with the vent tube, and just last week it took a dump after a 4 day cold snap. I bought it in 2004 and sears popped it out, checked it, and reinstalled a brand new one for free. I think I paid $90 for it in 04. Good deal as of just the other day, I'd say.

$.02

[John B.]

The Interstate battery installed in my 535i back in 2000 is still going strong after 7 years. Comparing the 60 month Interstate I pulled out of the 525i with the Duralast I bought today it's obvious the p/o cheaped out last time. It was about 2/3s the size of the Duralast & down on cca.