Re: [bmw] Replacing a battery on 99 E46 323

[Aleksandar Mitreski <mitreski@xxxxxxxxx>]

Mike

Thank you for your detailed reponse. Also thanks to Richard and Douglas
that dropped me an e-mail to warn me about the potential hazard of not
venting this battery. After I received an e-mail from Richard yesterday, I
called interstand and they confirmed that I need to install a Vent Hose
Adapter Kit (part number 358 355) that const few bucks. I called firestone
and told them about this. I was pissed because when they were mounting the
battery I asked them specificaly if they will plug in a hose to the
battery for venting. They assured me that there is no need for one.
Anyhow, we used the hose form the old battery to plug in the new battery,
so I should be explosion free for now.

Many thanks

Aleks

323i E46 1999 

p.s. For future ref, Interstate Batteries customer service number
800-541-8419 extension 6527

> 
> Date: Mon, 03 Nov 2003 16:41:09 +0000
> From: mkohlbrenner@domain.elided
> Subject: Re: [bmw] Replacing a battery on 99 E46 323 
> 
> Aleksandar Mitreski <mitreski@domain.elided> wrote:
> 
> > ... The only difference between stock BMW batery and Interstate MTP 91
> > is that the BMW has an exaust pipe that releases certain nitrogen
> gases.
> 
> Actually, it is hydrogen that is released from automotive batteries.
> 
> > The Interstate Batery does not relase any gases so there is no need
> > for an exaust pipe...
> 
> This isn't really true.  Modern automotive batteries tend to be of the
> "Sealed Lead Acid" type, but this is really a misnomer -- they all
> have a pressure relief valve in them in case too much pressure builds
> up inside.  During the normal course of battery charging, some of the
> water can be broken down into its components, hydrogen and oxygen.  The
> intent of "sealing" is that these components are retained and should
> recombine so that you don't have to keep adding distilled water like in
> the good ole' days.  However, if you either overcharge or charge too
> quickly, you can build up enough pressure that it needs to be vented.
> 
> I have worked with truly "sealed" lead acid batteries in my job and
> have seen them get surprisingly pregnant when overcharged.
> 
> The real difference between the OEM battery and your new battery is
> the presence of the hose, not the vent itself -- both have a vent and
> both WILL vent hydrogen under similar circumstances.
> 
> You should ask yourself why BMW chose to put this hose on your battery.
> 
> The answer is simply that since your OEM battery is in an enclosed
> space,
> rather than in the relatively well vented engine compartment, they had
> to ensure that any hydrogen released from the relief valve is vented
> to the exterior of the car.
> 
> If your new battery decides to release hydrogen, you will be venting
> this potentially explosive gas into your enclosed trunk.
> 
> To confirm my understanding on this subject, I did a quick search on
> "lead acid battery hydrogen vent bmw" which yielded, among others:
> 
> http://www.njbmwcca.org/Bulletin/bmw11-2002.pdf
> 
> This topic is discussed in the middle of that document.  It also
> mentions that you can get some sort of exhaust kit to retrofit to your
> new battery.
> 
> Regards,
> Mike Kohlbrenner
> 


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