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Plastic Battery Vent - What is this for?

10234 Views 21 Replies 7 Participants Last post by  bigboi3
So the plastic battery vent that goes over the intake, what is this for exactly and is there any downside of removing it?

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I think that it's more there to vent the possible accumulation of flammable fumes, which the battery may release in small quantities during operation.

I personally might be a bit hesitant to remove the vent without removing the cover as well, but possibility of any negative effects is pretty small.
The air being forced into the compartment is what vents it. Force air in, and the air that's in the compartment gets forced out some other way. If there was no air being forced in and vented out, then how would it cool the battery anyways?
Well, a battery is essentially a controlled chemical reaction. Due to the chemistry involved in a lead-acid battery, if you overcharge it with an excessive voltage, you can hydrolyze the water in the cells, causing it to vent hydrogen and oxygen. A mixture of hydrogen and oxygen is very explosive.

That duct won't do much to cool off the battery. What it will do is introduce just enough circulation to keep the battery compartment flushed of any gasses that may be vented.


EDIT: Okay, maybe I shouldn't say that it's not there to cool the battery, but keeping the batter compartment clear of hydrogen is a primary function.
[quote author=AzMz3 link=topic=67587.msg1170398#msg1170398 date=1169836993]
It is not to flush or vent gases!

lol... this seems to be kind of a sore spot with you, eh?
Well, to be perfectly fair, it's not false info. An improperly-charged battery canvery well release hydrogen gas, and hydrogen gas is extremely flammable, and a vent will flush the battery case of any gases that may have otherwise accumulated.

Just because a service manual doesn't explicitly state something, doesn't make it false.
But I'm not just "assuming" that batteries can release hydrogen... it's a fact. Unlikely, yeah, but still a real possibility.
[quote author=AzMz3 link=topic=67587.msg1172887#msg1172887 date=1170002707]
There are some cars that don't have air ducts and enclosed batteries.....where is your theory there.

If the battery isn't enclosed, then there would be no place for hydrogen to build up--engine bays are pretty well ventilated. I could just as well turn that around and say "If that vent is there to cool the battery, then what about the cars with no ducts or covers?" Read a little further to see why I'm not going to use that argument.

[quote author=AzMz3 link=topic=67587.msg1172887#msg1172887 date=1170002707]
Anyone can assume what it is made for but having what it is actually made for in writing by the people that made it is alot more believable than your assumptions!

"My" assumptions, eh? Sorry, I'll stop assuming about the physical reality of the chemical reactions that occur when charging a car battery, and only believe what a manual tells me. Honestly, man, that manual is not the comprehensive, end-all resource for every detail of every function of every part of this vehicle. If it tells me something, I'll believe it. But not at the complete exclusion of things it doesn't tell me.

To be honest, it seems like you're just trying to be argumentative here. If the vent cools the battery by flushing the airspace inside the compartment, then it will also dissipate any hydrogen that may accumulate. Those functions are mutually inclusive! Where's the problem? Or are you trying to tell me that there is no possibility of a battery releasing hydrogen? If so, show me some proof and I'll shut up.

I'm not telling anyone what to do with that vent. I never even said that removing the vent was necessarily a bad thing. If you wanna take it off--fine, there's more than likely no problem at all. But what the hell's so wrong with trying to inform people of a potential concern? It's not like I'm pulling this stuff out of my ass; I'm just reporting the facts here.

Anyways, I've said my peace--I gave the info I wanted to give, and I think I made the point I wanted to make. People can make of it what they will.
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