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Sun Nov 09, 2014 11:22 pm

I just want to shed some light on something that many people that add aux. batteries to their vans seem to miss.

Rather than explaining it myself, here is some info direct from an auto parts website:

"Never install any type of battery in a completely sealed container. Although most of the normal gasses (oxygen and hydrogen) produced in an SVR battery will be recombined and not escape, oxygen and hydrogen will escape from the battery in an overcharged condition (which is typical with any battery type).

For safety's sake, these potentially explosive gasses must be allowed to vent to the atmosphere and must never be trapped in a sealed battery box or tightly enclosed space!"

This is why in the RV industry you always see batteries on the tongue of a trailer in a vented box, in an outside compartment that isn't sealed, or in a battery box with a hose to the outside.

Some AGM batteries, like the ones I use, have a vent on the top onto which a small hose can be attached and vented to the outside.

More battery info:

http://www.carquestprofessionals.com/batteries/faq_myths.html

Mon Nov 10, 2014 5:19 am

Very good "public service announcement"

If you choose wisely, your new battery will have a built in gas collection system and a port to hook a hose to thus venting the fumes to the outside.........

Dave

Mon Nov 10, 2014 10:35 am

It's been discussed a few times before. The amount of hydrogen produced by one battery in an over charging condition is in no way dangerous inside the westy. Others with knowledge agreed.

http://www.thesamba.com/vw/forum/viewtopic.php?t=395836

http://www.thesamba.com/vw/forum/viewtopic.php?t=501164

Mon Nov 10, 2014 1:26 pm

PDXWesty wrote: It's been discussed a few times before. The amount of hydrogen produced by one battery in an over charging condition is in no way dangerous inside the westy. Others with knowledge agreed.

http://www.thesamba.com/vw/forum/viewtopic.php?t=395836

http://www.thesamba.com/vw/forum/viewtopic.php?t=501164

It isn't breathing the gases and ill health effects that concern me,

It is the corrosive nature of the gas.

Anyone who has ever owned an Air Cooled Beetle or Karmann Ghia is keenly aware of the damages caused by Batteries!

Dave

Mon Nov 10, 2014 7:17 pm

Just like living near power lines or drinking reverse osmosis water, there are arguments for both sides.

My post was intended for people that may be concerned about such things but aren't aware of the potential risks and therefore may not search for the info.

From experience a sulfated battery can give off a rotten egg odor, a smell which is usually not associated with good things ;-) Should this happen to a battery contained inside the vehicle, venting would make the rest of a camping trip far more comfortable.

djkeev wrote: Very good "public service announcement"

If you choose wisely, your new battery will have a built in gas collection system and a port to hook a hose to thus venting the fumes to the outside.........

Dave

Those are the batteries that I am using now. Western Star (big rig manufacturer) uses these since the trucks have their batteries under the passenger seat. As you mentioned, they vent to the exterior using hoses.

Mon Nov 10, 2014 7:50 pm

As djkeev mentioned, the corrosive gas attack from an overcharging battery is what causes most of the damage. In marine applications I have had to replace inverters, chargers, navigation equipment, computers, thermostats, and various other electronic components that were mounted above or in the same compartment as overcharging batteries. AGM batteries aren't a solution to this either, you overcharge an AGM far enough and it will swell, crack, and off gas.

VW thought that the hydrogen from a charging battery was enough of a concern that all of the the Westys got sealed battery boxes vented externally since they were in a 'living space' instead of the flip up lids that the tintops have.

Mon Nov 10, 2014 8:13 pm

I don't know. The Westy models without a stove got unsealed flip up box lids, even models with 2 batteries. So a dining table area and sleeping space for 4 people with batteries in both boxes and no external battery box vents. Not much sign of concern there.

Mark

jstar89crx wrote: .....
VW thought that the hydrogen from a charging battery was enough of a concern that all of the the Westys got sealed battery boxes vented externally since they were in a 'living space' instead of the flip up lids that the tintops have.

Mon Nov 10, 2014 8:36 pm

Great observation Crazyvw, I have never owned a weekender. So it must be an ignition source (stove) that dictates if the battery was in a sealed box or not.

Mon Nov 10, 2014 8:58 pm

where is the aux. battery vent on a Westy?

Mon Nov 10, 2014 8:58 pm

All I can figure is that it relates to the stove. The parts installed into the battery box to create the seal and vents are pretty crude and my speculation is that Westfalia did that part as part of the camper gear installation. I wonder if European market camper models got the same sealed boxes? Any Europeans out there know about this?

Mark

Mon Nov 10, 2014 10:32 pm

My 1986 Multivan "Weekender" has the sealed battery box with vents just like the main battery box has.

You can see the top paper vent tube and also make out the bottom inlet hole in this photo.........

Dave

Mon Nov 10, 2014 11:10 pm

Think about where the vent is located....at the bottom of the box. It's for and liquids to escape, not gasses. It's not for hydrogen. Hydrogen gets dangerous in concentrations above 2% and is lighter than air. The box would have to fill with hydrogen before it vented at the bottom of the battery box. It's much more likely the bottom vent is for spilt acids from the battery.

Mon Nov 10, 2014 11:49 pm

PDXWesty wrote: Think about where the vent is located....at the bottom of the box. It's for and liquids to escape, not gasses. It's not for hydrogen. Hydrogen gets dangerous in concentrations above 2% and is lighter than air. The box would have to fill with hydrogen before it vented at the bottom of the battery box. It's much more likely the bottom vent is for spilt acids from the battery.

You are correct, there is a vent hole at the bottom,
But......

There are vent gas holes at the top of both boxes. A vent hose directs the fumes out of the battery box, thus out of the passenger cabin.

Dave

Tue Nov 11, 2014 1:52 am

jstar89crx wrote: .....
VW thought that the hydrogen from a charging battery was enough of a concern that all of the the Westys got sealed battery boxes vented externally since they were in a 'living space' instead of the flip up lids that the tintops have. crazyvwvanman wrote: I don't know. The Westy models without a stove got unsealed flip up box lids, even models with 2 batteries. So a dining table area and sleeping space for 4 people with batteries in both boxes and no external battery box vents. Not much sign of concern there.

Mark

My 1990 full-camper (battery boxes are factory original):
Sealed starting battery box with annoying screw-on lid and external vent.
Un-sealed aux battery box with flip-up lid and no external vent.

Call me an idiot, but I'm more concerned with battery acid leaking out than with my maintenance-free sealed batteries (one being an AGM) off-gassing.

Tue Nov 11, 2014 2:13 am

djkeev wrote:
You'd also need quite a bit of liquid in there to get over the lip of the bottom-most "drain" / vent hole.

I wish we could find a crew of the Vanagon and Westfalia folks, retired of course, and ask them all kinds of interesting questions! :)

Tue Nov 11, 2014 6:42 am

djkeev wrote: PDXWesty wrote: Think about where the vent is located....at the bottom of the box. It's for and liquids to escape, not gasses. It's not for hydrogen. Hydrogen gets dangerous in concentrations above 2% and is lighter than air. The box would have to fill with hydrogen before it vented at the bottom of the battery box. It's much more likely the bottom vent is for spilt acids from the battery.

You are correct, there is a vent hole at the bottom,
But......

There are vent gas holes at the top of both boxes. A vent hose directs the fumes out of the battery box, thus out of the passenger cabin.

Dave

Wouldn't driving @ speed create negative pressure, "sucking" air out the vent hole? That removes any fear I have of hydrogen gas build up & why I kept my vents open & mouse-blocked w/ stainless scrubbers.

(plus the vents are raised a bit from the bottom of the pan - there would need to be a scary amount of liquid {acid} sloshing around down there to make it out the {paper} tube)

Tue Nov 11, 2014 8:21 am

Yes, an airflow exchange is my theory!

The top vent points down, the bottom vent has a forward facing scoop to collect air while in motion. A reason to keep the battery cover sealed and screwed!

Bottom scoop (stuffed with Stainless Steel Wool) ......

Both battery box vents looking into the wheel well over the front wheel.......
The round tube on top is the upper vent hose termination.......
The photo is dark but to the right of the Steel Wool......

Dave

Sat Aug 01, 2015 7:38 pm

So what do people do to close up or stop the hole from taking on road debris/water?

That is from our 86 Weekender we just acquired from the original owners.

I don't like the hole there, and don't like how it can trap water/dirt.

I opened up the Aux battery compartment and I am 99% sure I was the first person to ever do this. The original VW aux battery is in there!

I love finding unmolested VW's!

Sat Aug 01, 2015 8:59 pm

kamzcab86 wrote:
My 1990 full-camper (battery boxes are factory original):
Sealed starting battery box with annoying screw-on lid and external vent.
Un-sealed aux battery box with flip-up lid and no external vent.

Ditto my '87 with PO-added aux battery. It vents into the interior of the van which I can assure you is not a sealed environment. The starter battery is more tightly sealed.

Sat Aug 01, 2015 9:15 pm

The aux. battery box under drive seat on my '81 Westy has a partial flip up lid. It clearly vents to the bus interior. I am not concerned about this.

That hole shown in jereandjess image likely had a hood over it at one point. I recall that my '88 Westy starter battery box had that hood. It was close to falling off. I painted it up and everything but never did get around to putting it back on.

shame on me. ;)

Neil.