Battery vents - leave one plugged?

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GLK

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I replaced an old (10yrs) battery not long ago, with a top-of the range VARTA model. It had a big red letters instruction sticker, telling me to remove the bungs immediately,- fine, I did that, of course.

Once installed, with one of the vents connected to the breather pipe, do I leave the second vent open (rather counterintuitive), or do I plug one of the two transport bungs back in? The battery is a sealed, maintenance-free modern type.
 
Without knowing the design of the battery, it's rather assumptive to just use one of the vents. Unless you can be sure that both vents are connected, I'd personally do as instructed by the manufacturer and unplug both vents.
 
The potential risk of leaving the vent open and not connected to a breather pipe is that the flammable gas could get ignited by a spark or hot exhaust pipe etc.

The potential risk of blocking the vent is that the battery could explode...

Some 35 years ago I had a battery explode under the bonnet - not a pleasant experience. My first thought on hearing the very loud bang was that I have been targeted by the local Mafia.. :D. The entire top of the the battery was missing, with acid dripping everywhere, seriously damaging the paintwork.

It was the original FIAMM battery that came with my 1-year old Alfa... to this day I don't know why it exploded, possibly a blocked vent, or possibly ignited gas - no idea.
 
Thanks chaps, appreciate the input. The battery is a small 027 one and sits under the driver's footwell, so no risk of hot exhaust pipe starting a fireworks, etc.

The battery compartment is designed with one breather pipe, on the [+] side, and it is connected.

I've looked through VARTA guide again, and it does not say what to do with a second vent, as far as I can see.

Logically, I feel it should be plugged, otherwise what's the point having a breather pipe on the other end?
 
Thanks chaps, appreciate the input. The battery is a small 027 one and sits under the driver's footwell, so no risk of hot exhaust pipe starting a fireworks, etc.

The battery compartment is designed with one breather pipe, on the [+] side, and it is connected.

I've looked through VARTA guide again, and it does not say what to do with a second vent, as far as I can see.

Logically, I feel it should be plugged, otherwise what's the point having a breather pipe on the other end?

Last sentence, left column... :thumb:

 
Last edited:
....Logically, I feel it should be plugged, otherwise what's the point having a breather pipe on the other end?

...for different applications, i.e. to allow the battery to be fitted either way? I am guessing.
 
I believe, I found the answer, and it is as thought, and as Mr Kripling and moonloops have suggested: VARTA Automotive - page 5 (if you read it in English ;) ) - last section of para.1:

Leave at least one gas outlet open to avoid the risk of explosion. This also applies to the transport of used batteries.

So, it appears both vents are connected, and with one open into a breather pipe, the other can be (and should be) plugged :thumb:
 
ha-ha, moonloops you type faster than I am
 

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