Solar battery venting?

[tomas_maly]

I'm curious what are the various ways people go about venting their batteries when left inside the vehicle? These are deep cycle (109 Ah) marine batteries bought from Wal-Mart.

Seems that my options are to either do some welding to devise a storage tray underneath (seems like a lot of work), or just create an airtight box for storage on the inside, with some venting system to the outside. I've searched around on this site and have only seen one or two interior setups. I was thinking I could create a storage box (with plywood) underneath one of the bunk beds.

Now I happen to have hole saws, I'm not sure if it's easiest to just have a PVC pipe go straight up thru the ceiling, or thru the side wall (less material/distance), or something else. I've seen a setup where someone used a P-trap for venting, but I was thinking of just having the vent on the side so the top lid doesn't need a hole through it (since it'll be resting below a bed).

I've also briefly thought of keeping one window cracked about 2 inches and creating a wood frame 'ductwork' that is as wide as the window and goes all the way up. I actually am double insulating the vehicle - putting R-13 insulation in the steel cavities and then another R-6.5 foam paneling on another interior layer. Normally this would extend the wall inward another 1 1/2 inches (2x4 laid flat), and I can perhaps (for just this one window, or at least part of it) exclude some of the 1 1/2 inch foam insulation to create a gap where the gases can flow out from the battery box. I probably would not leave an entire window width for the venting, so I'm curious how wide (assuming it's 1 1/2" thick and 2" tall) is probably sufficient for (up to) 8 12V batteries? The box would otherwise be airtight - I'd make a plywood frame with a lid that uses wingnuts to tighten them down, and probably epoxy/etc to seal the edges just in case.

Or another option I could do is leave the box as a bench way in the back against the back wall and cut a rectangle in the rear wall thru the exterior (below the stop lights) and use an old propane hood vent (scrapped from a used stove setup) on the outside. That might be the most obvious. I just have to see if the stove vent is long enough to fit through the whole wall (probably).

[lornaschinske]

http://www.rv-boondocking-the-good-l...tterybank.html scroll down about halfway.

We will simply clean up one of the original battery bays, spray it with Rustoleum Leak Seal (at $10 per can) to protect from acid damage and to seal up after cleaning all the rust out. It will hold our(3 or 4) deep cycle RV/Marine Batteries (840 amp each) The previous batteries did a real number on the compartments (the roll out trays were almost completely destroyed). We will do the same on the other battery compartment which will be our "electrical" compartment (hold smart charger, electrical cord & plug, cable/Dish TV hook up, adapters & test equipment). The battery compartments have a series of holes drilled into them to vent the batteries.

[roach711]

My setup is pretty close to what you're thinking about. I built a plywood box with a bolt-on lid and sealed it up with some fiberglass resin I had left over. I used some closed-cell foam weatherstripping to seal the lid. Venting is through a cut-down sink trap epoxied to the lid and to go through the bus wall I bought a venting kit from Dyers RV for about 10 bucks or so. When I need to get at the batteries I unscrew 4 wing nuts and undo the sink trap nut so I can remove the lid.

My batteries are stored in the bottom of a closet so I had space above the box for the vent, but I'd think you could cut your vent into the side of the box near the top and still be OK.

Here's a link to the vent kit:
http://www.dyersonline.com/mts-replacem ... white.html

[tomas_maly]

I think I am going to go with cutting a rectangular vent hole in the rear wall and attach a typical hood vent from the outside, which will just go into the box on the upper portion of the back side. I think the box will then be turned into a bench of some sort.