What is the best way to vent a battery box? The homemade wood box is in my front 5th wheel storage compartment (just below the hitch). I was going to vent it out to a new vent hole on the passenger side. DO I need two vent holes (one for fresh air and one for gasses)? I currently have a Freedom 458-20 with the remote panel and was thinking about splicing into the "inverter" on button and mounting as small inline fan. Don't know what some of the options are there. OR do the batteries not really put off that much gas while just sitting there? The compartment that the battery box is going into is not sealed by any means on the passenger side and vents itself.

My Bats. are inside so I vent them to the outside. I had to modify one of my boxes.">clicky

My fifth wheel has a battery VENT to the upper right hand side of the front access door. I have two vented battery boxes sharing this one vent hole that looks similar to this google images photo. I got my venting hardware and tubing from LOWES... My two battery boxes sits down in the recessed area just behind the front access door. I also drilled some fluid drain holes to drain out thru the floor of the storage compartment in case my converter/charger boils out some battery fluids from over charging... Looks similar to this google image...If I was going to mount four batteries in this area I would go with something like this install I have seen on google images. You can see the vent tube in the upper right hand area of this photo. The top shown below seals off the wooden box used in this google images to house the four GC2 batteries sitting end to end...Roy Ken

The vented box I purchased had two holes. One in the bottom and one in the top. Air cannot exhaust if air cannot get in.

You are supposed to have vented boxes but I was too lazy and hoped the cargo bay was vented enough. So I have batteries up front not even in boxes. I keep waiting for the fumes to destroy my inverters parked nearby, but after five years the inverters still work.As the man said after falling off a 20 storey building, when passing the 10th floor, "So far so good."

BFL13 wrote:You are supposed to have vented boxes but I was too lazy and hoped the cargo bay was vented enough. So I have batteries up front not even in boxes. I keep waiting for the fumes to destroy my inverters parked nearby, but after five years the inverters still work.As the man said after falling off a 20 storey building, when passing the 10th floor, "So far so good."That is how I was rolling. But I am adding two more so I figured a box was about time. Just trying to figure out where I get the battery box hose fitting/flange. I can get the round vent for the RV all day long. Just need the box flange.

Battery Box Venting Question | Good Sam Community

20 Replies

myredracer
Explorer II
Nov 09, 2015
Old thread, but MTS Products makes the box, exterior vent and hose like in the photo. This particular one is commonly installed in FWs by the RV manufacturer. Readily available and I bought them from a local RV dealer. Usually white and I wanted a black vent which took a long time to get. The upper and lower halves of the box are the same and have a flange in them for the hose as does the exterior vent.

When researching battery boxes last year, I read that the exterior vent should be min. 6" above the top of the box. I used pass-through terminals to seal up better. Some googling will come up with some good venting design info. like this from BD Batteries.
bkirkpatrick
Explorer
Nov 09, 2015
Ground Zero? Thermo Runaway? What we are talking about is that, at least for my Keystone Raptor, there is so much "fresh air" space in the front hatch area that how can there possible ever be a buildup of gas in there.

I have had my toy hauler for 10 years and in that compartment was a 600w inverter, a freedom 458 2000w inverter / charger, 2 batteries, and never had a problem. No corrosion on any of the electrical items there, nothing... I have camped in the desert with 100+ and < 0 temps. No issues ever with that compartment.

Although at times I wish there would be a thermo runaway on my rig so I can get a class A.
grizzzman
Explorer
Nov 09, 2015
bbaker2001 wrote:
thanks bkirk
I cant imagine batteries giving off enough gas to cause a problem where there is that much cubic ft of air space.
I have always had a TT so never an issue, but want to be sure.

Spoken like a person that has not been at ground zero durring a battery explosion or a thermo run away for that matter.
Tends to give ya a whole new perspective.
Good luck with your project.
bbaker2001
Explorer
Nov 09, 2015
thanks bkirk
I cant imagine batteries giving off enough gas to cause a problem where there is that much cubic ft of air space.
I have always had a TT so never an issue, but want to be sure.
bkirkpatrick
Explorer
Nov 08, 2015
bbaker2001 wrote:
since my whole front and front storage is open, would that not be enough air flow without a vent pipe.
or is it better to mount in box

That is what I always thought. Everyone said never put any electronics under the belly of the 5th wheel in that compartment but it is by far from a sealed compartment like you said. I never had a problem with my batteries there or any issues from "hydrogen gas" from the batteries.
bbaker2001
Explorer
Nov 07, 2015
since my whole front and front storage is open, would that not be enough air flow without a vent pipe.
or is it better to mount in box
wa8yxm
Explorer III
Mar 04, 2014
Personally I like to vent bottom and top-side.

Bottom, drill a hole and put in a PVC pipe section (perhaps 1-2 inches is all you need) this way heaven forbid a battery "Explode" (more pop than boom, won't likely damage the plastic box if you used a plastic box) the acid drains out all plastic to the ground and does not eat the battery tray/compartment.

Since you used wood.. acid will turn it into scrap wood mush, easily replaced so do not worry about it.

Top is for venting the gasses out.. Others have addressed that vent quite well

Only the top vent is needed.. So you can use like half inch for the bottom drain.
McKenziek
Explorer
Mar 04, 2014
Kind of difficult to see but i have an intake w/filter at the bottom of the right box with an exhaust to the upper left.
BFL13
Explorer II
Mar 03, 2014
From other threads on this topic, it seems there are two hazards:

1.- gas fumes that rise
2.- damp fumes from heavy charging that go down

I am not sure what form of covered box with holes in the bottom and venting on top solves what.
bkirkpatrick
Explorer
Mar 03, 2014
If hydrogen gas rises, why do many of the battery boxes vent out at the side towards the top AND why do many installations show the vent tube running down and out? If hydrogen rises, what happens if the vent tube starts to dip downward like many of the trunk mounted boxes? Also, would the optimal vent be on the lid or top part? The return air should also be at the bottom?