# Battery ventilation



## jonesy1 (Sep 28, 2008)

I am about to replace my 90amp/hr sealed battery with 2 larger

open ones. The battery locker is situated under a seat in the

habitation area. Do I understand correctly from the article below

that what I need to avoid any danger from hydrogen gas is to drill

2 * 50mm holes through the floor

(avoiding all pipes), and 2*50mm holes at the top of the locker to

the outside?

Is the science on this solution valid?

If so assuming I use plastic tubing to the outside wall, what do I

use to finish the job and make it look neat?

http://www.caravanandmotorhomebooks.com/articles/battery_enclosures.htm

Thanks

Les Jones.


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## DABurleigh (May 9, 2005)

Les,

Just use Halfords washer bottle tubing from the port on your battery through a small hole in the floor. Protect the tube with a grommet or glue from a glue gun as it goes through the floor.

Dave


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## joedenise (Jul 20, 2007)

hi Les 

you could always buy sealed batteries.

joe


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## DABurleigh (May 9, 2005)

IMHO sealed batteries in the habitation area still require venting to outside. Excess hydogen can be generated at a dangerous rate by either a cell failure on a good charger or a charger failer on a good battery.

Dave


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## sallytrafic (Jan 17, 2006)

Wholeheartedly agree. I have been a few feet from a sealed battery that looked like it was becoming a rugby ball.


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## jonesy1 (Sep 28, 2008)

*battery ventilation*

Thanks for that. I will buy suitable batteries and do as advised.

DA Burleigh I have sent you a p.m.

Les Jones


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## coppo (May 27, 2009)

Hi Les
As you know this is a problem i am having.

The holes in the floor are easy but obviously impossible to do in the top of the battery locker which is where the problems then begin.

Mine is (battery locker) is also under a side seat built into the floor.

The guy who fitted(and subsequently removed because of safety he said)my 2 6 volt ones is now suggesting an airtight cover for the battery box(difficult due to cables etc) and using a brushless fan on the wall of the box to extract air outside. Apparently the fans are very low powered.

You can get recombination caps which, the manufacturer states, deals with 90% of the hydrogen, recombining it.

Paul.


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## teljoy (Jul 4, 2005)

sallytrafic said:


> Wholeheartedly agree. I have been a few feet from a sealed battery that looked like it was becoming a rugby ball.


Frank,

Sorry to butt in on this thread but you now have me worried. Not being very experienced in elecktrickery I had a new leisure battery fitted last year which was of the sealed type so there is no aperture to fit the pipe that was inserted in the previous battery. The battery is under the drivers seat so not completely enclosed.
The guy that does my habitation checks and servicing assures me that I do not need the vent pipe on this type of battery.
Surely if it is a genuine leisure battery, which it is marked as such I must believe him?

Terry


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## Antonia (Apr 27, 2008)

Hi all

Erm....Hydrogen is lighter than air, as such it rises!

It will rise up ito the air of the cab/house to the ceiling where it will gather or pass out the vents.
If you can pass a small plastic tube ( from B&Q ) from battery vent ( if it has one ) out to underneath the van then may help. However seal the hole.

Regards

Antonia


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## Mike48 (May 1, 2005)

Do gel batteries need venting?


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## DABurleigh (May 9, 2005)

Again, IMHO, yes. People easily confuse low maintenance, in terms of topping up batteries, with safety issues. 

Gel/ sealed/ valve regulated/ recombinant cap batteries can obviously help - WITH THE CORRECT CHARGING REGIME - to minimise the need for checking battery levels and topping up. Of course, you can also do as I do and buy cheaper flooded lead acid cells and minimise the maintenance requirements by the charging regime, too. 

The real compromise is between maximising the charge the batteries can hold versus the topping up requirements; and this compromise doesn't need sealed batteries.

As to safety, any lead acid battery can generate excess hydrogen under fault conditions. So you should ensure this can be discharged.

Then again, it's a bit like reverse polarity. Never a problem for many, who go in blissful ignorance or wonder what the fuss is about in the light of their own experience, simply because the fault condition never strikes.

Dave


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## teljoy (Jul 4, 2005)

DABurleigh said:


> Again, IMHO, yes. People easily confuse low maintenance, in terms of topping up batteries, with safety issues.
> 
> Gel/ sealed/ valve regulated/ recombinant cap batteries can obviously help - WITH THE CORRECT CHARGING REGIME - to minimise the need for checking battery levels and topping up. Of course, you can also do as I do and buy cheaper flooded lead acid cells and minimise the maintenance requirements by the charging regime, too.
> 
> ...


Hi Dave

I have already asked a question of Frank earlier in this thread. He is not online yet so has not replied but if you read my post my battery is under the seat in the cab area and does not have any aperture to insert the plastic pipe that was attached to my previous battery. I am assuming that as the battery is contained in a fairly open area with ventilation around that it is sufficient?
Your comments would be appreciated.

Terry


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## DABurleigh (May 9, 2005)

Terry,

It depends if you enjoy having a bomb a few inches under your nether regions in the event of a cell breakdown or charger failure 

The question is, can you convince yourself you won't have a build-up of hydrogen nor the possibility of a spark there?

Dave


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## teljoy (Jul 4, 2005)

DABurleigh said:


> Terry,
> 
> It depends if you enjoy having a bomb a few inches under your nether regions in the event of a cell breakdown or charger failure
> 
> ...


Dave

Are you saying that these type of leisure batteries should not be sold? 
Also that they should not be under drivers seats?

There must be hundreds of these batteries installed in the same situation as mine. Certainly worrying if true. How can they be sold in these times of "health and safety"? How many of us are driving around like this?
Terry


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## Mike48 (May 1, 2005)

I had a gel leisure battery fitted last week under the driver's seat on a Fiat Ducato. Its not in the sleeping area. There is no provision for the battery to be vented. I am unconcerned. Surely if the battery was intended to be vented there would be provision for a vent tube. There must be hundreds of vans in a similar position.


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## DABurleigh (May 9, 2005)

"Are you saying that these type of leisure batteries should not be sold?
Also that they should not be under drivers seats? "

No.
Yes, IMHO.

I can only give my advice backed up by reasoning. It is for others to ignore or put up a counter argument beyond "you must be wrong as you seem in a minority".

Dave


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## jonesy1 (Sep 28, 2008)

Just for further information, on my Burstner van on a Ford transit, the 

battery under the drivers seat has a vent pipe which is connected and 

goes through the floor, put in by the manufacturers. In the battery 

compartment under a seat in the habitation area, there is also a vent 

tube which goes under the floor, which I shall be using . It goes to 

show that some manufaturers are aware of the potential problem.

Les.


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## OwnedbyCollies (Dec 7, 2009)

We, too, have a Burstner Nexxo and have just had an additional leisure battery fitted. 

The original is vented and I queried why the electrician did not vent the second. I was reassured (!! 8O ) that there was no need and modern batteries are quite safe.

Needless to say we will add a vent to the second battery and plan to extend the vent with a t-tube from the first battery - is this a cunning plan?? Any advice gratefully accepted!


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## Antonia (Apr 27, 2008)

*HYDROGEN RISES UP*

O for goodness sake

HYDROGEN floats....lighter than air, up to the roof !
So unless you battery is inside a sealed container the gas will escape to air and go up UP to were the vents are. It will not form a bomb under your seat.

Antonia


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## DABurleigh (May 9, 2005)

So think of the hydrogen under the seat as like the hot air in a balloon - it rises but can't get out, so forms a pocket of inflammable gas as it is being generated by the battery.

Dave


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## Antonia (Apr 27, 2008)

DABurleigh said:


> So think of the hydrogen under the seat as like the hot air in a balloon - it rises but can't get out, so forms a pocket of inflammable gas as it is being generated by the battery.
> 
> Dave


No, Diatomic hydrogen is an extremely small molecule, it will difuse out through ANY small hole, crack or through fabric, it will not be contained unless sealed in tight, at the rate at which a lead acid cell would produce hydrogen it would escape though your upper vents.

The only logic for a vent in a not sealed container would be for corrosive liquids from the battery. These batteries have a small vent tube that should vent to outside. Do not mistake the need for this as the need to vent Hydrogen. Other gasses found in vans however should be provided with vent holes as they are heavier than air.

Antonia


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## DABurleigh (May 9, 2005)

I think we shall agree to disagree 
http://jgdarden.com/batteryfaq/carfaq14.htm#explode

My batteriers are under my seat. The seat box is a large metal box. The only hole is at the bottom. I'll have my vent tube to get rid of the hydrogen in case it ever gets generated by a fault, thanks.

Dave


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## pieterv (Feb 3, 2009)

DABurleigh said:


> I think we shall agree to disagree
> http://jgdarden.com/batteryfaq/carfaq14.htm#explode
> 
> My batteriers are under my seat. The seat box is a large metal box. The only hole is at the bottom. I'll have my vent tube to get rid of the hydrogen in case it ever gets generated by a fault, thanks.
> ...


Thanks for the link. It refers also to internal battery explosions, when the Hydrogen doesn't (or can't?) escape and a fault condition causes a spark inside the battery.

Looks like venting won't help us there!


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