Technical Moving Battery to Trunk-Should I Vent?

After 20+ years of having the battery in a tray neatly hidden under my A coupe, old age makes a move to the trunk most desirable. The fuel tank (vented to outside) is also in the trunk. I've figured I can run cables (1/0) through the trunk floor and under the body to connect with the existing cut-ff switch and charging posts.
I'll definitely was a battery box for safety and appearances but do I want a vented box like this NOCO or a vented metal box or does it not matter if I vent the battery through the floor? Are Walmart's batteries all made with ports for venting?

These are photos of the trunk area and battery boxes. All help desperately appreciated.


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Either vent that lead/acid battery or buy an AGM battery.

 

AGM is the answer . Best bang for your buck spent

 

Both replies above are correct. A true AGM does not need venting, the one you posted does. The only battery allowed in hospitals for IV and defibs are Odessey AGM batteries. That tells you something. I have 3 of them in my cars, Odessey PC925. Expensive but worth it.

 

So you know you are in a cheap IV if they have lead acid batteries. Should have gone with the more expensive health plan.

 

I have a sealable Moroso black plastic box in my 32's trunk. I have a vent tube that runs from it thru the floor.

 

My off topic daily driver came from the factory with the battery in the trunk. It's vented with a hose that runs directly from the battery out the bottom of the quarter panel, but it just has a hold down bracket to hold it in place, and there's a plastic cover so you can put luggage in the trunk without shorting the terminals.

 

I guess I'm confused if you vent the battery box out of the trunk every opening including cable openings have to be sealed or it's a waste of time. Then the gasses generated are probably going to stay in the box since there's no air flow so isn't that creating another problem?

 

I'm the guy that put Bandit Billy onto the PC925. Making him happy is a pretty high bar to reach. I have them in 4 of my cars and he says I'm Impossible to make happy. When you can get 9 years out of 1 Battery and another one just turned 7 and still Cranking just fine, we must be onto something that's right. No vent tube needed. Here's my little powerhouse 925 nestled right up to my Gas Tank. Don't have the********* it in this photo and Yes, it's mounted on its side and will be just fine like that.

 

One more thing I like about these units. You can mount just Ring Terminals without posts, or you can install the normal Post to that Batt.

 

I kind of wondered that,too.

 

I have had cars with batteries in trunk with no vents, no problem.

 

When I bought my boat ten years ago it came with one and it's still cranking like a beast. All I do is remove it in winter and keep it in my heated garage. They are awesome.

 

The old VW Beetles had a lead acid battery under the rear seat that wasn't vented to the outside. IIRC. Just saying.

 

My personal thoughts about venting is this. Lead acid fumes are caused by overcharging. This was not uncommon back in Generator days. I still believe that a sticking regulator was the problem. Once on to Alt's and solid state reg's that dropped way off. Solid state either works or doesn't, seldom do they overcharge. This was so dependable the Batt makers came up with sealed top Batt's. My bottom line is use whatever Battery you want, just keep your charging system healthy and screw the Vent system. The worst thing that might happen is an overcharge and venting of gasses will remove a little paint and maybe damage some carpet. Leave the Deck Lid closed and nobody will know.
P.S. Don't put an old unregulated charger on a led acid battery to charge and close the deck lid!

 

Mine is vented in a sealed box in the Henry J per NHRA rules, since it's inside the passenger compartment



In my 41 pickup it's just in a regular non vented box like many of my racing buddy's cars with a trunk that have bulkhead isolating the passenger compartment

 

While working with MB on the acquisition of their G-Wagon for the Canadian military, we had one of the battery compartments on one of the test vehicles “explode” from hydrogen gas. The battery compartment was also covered by ballistic plate as well. The top cover was blown off and bent the hood pretty good. I believe it was an AGM battery but could be wrong. They ended up adding a vent tube to the production vehicles.

 

I appreciate the varied responses. Model a Gomez in Post #8 had a good point about sealed/unsealed boxes. Turns out that the batteries I likely will use-Walmart-good price good luck-the one in there now i from 2014- come with vents. So I'm just going to runa vent tube through the floor and keep the lid open if I'm not driving the car.

 

I had a friend call the other night in regard to his garden tractor. The battery went flat and exploded when he went to charge it as he clamped on the connectors. Very likely an overcharge like @Pist-n-Broke suggested. He was outdoors and the battery was small so not much damage that a box or two of baking soda couldn't take care of. That's why they put those stickers on or near batteries about making the last contact away from the battery on a good ground.

 

One time in my above mentioned 41 I twisted on the pretty tight battery cables to give the truck it's once a month start, no lid on the box.
I got in the cab and as soon as I hit the key



It sounded like a 12 gauge going off, I've got 15 ft ceilings and there were parts of the battery case in the ceiling ! That freaking acid sprayed all over everything too.

 

I had one blow up in my face once. Fortunately, I was wearing sun glasses, which kept the acid out of my eyes...and I was at a lake, so was able to run for the water. Got to the water just as the acid was starting to soak in and sting

 

An A trunk doesn't seal well enough to keep the hydrogen from floating out of it...........

 

Years ago I shared a house with a guy who was a mechanic. He had one of those shiny jackets that the distributors gave away. I believe it was from Purolator but not positive. Anyway, one day he was wearing it while leaning over the battery on a SBC to get to the distributor. Battery went Kaboom.****umed that a static spark caused the explosion. Needless to say the battery and the jacket were toast. Burnt toast.

 

Here is the vent set up for GM cars, it plugs on the battery vents. Then run it through the floor. https://www.ebay.com/itm/402743494383

 

The Tiger had a battery with a cap on each cell . Each cap was connected with a piece of tube and the last one exited the car through a hole punched through the floor .

 

I moved the battery to the trunk of my 65 Barracuda 40 years ago. Battery tray is from a GM car in junk yard, bolted to floor.
I have never vented or covered the battery. Has worked fine all these years. No damage to paint or carpet. Didn’t know much then and guess I still don’t.
Your results may be different, just stating my facts.
( and I too have seen a battery explode, .....trunk of a BMW) loud and messy.

 

Same for Fiat Topolino, behind the drivers seat with a little hinged lid .

 

The New Ford Transit vans come with batteries mounted under the drivers seat, the one we use at work have dual AGM since they have power inverters. The two batteries have small vent tubes coming right out of the top with the stiff tube running down the side and out the floor board.

 

I've got the same (or very similar) Moroso box in my son's car. The box and vent are well made, except for the quarter turn lid fasteners. Not too happy with how they lock, and not confident they will stay locked under constant rural road vibration (my son drives the car like a threshing machine. It only has two speeds - flat out, and stop). The receiver tab holes for the quarter turn locks make them harder to replace with simple bolts. YRMV.

Cheers,
Harv

 

I have a plastic box in the trunk and ran a piece of 1/4" tube from the bottom of the box straight down and into the airflow under the car, with the end cut at an angle. The top cover is not airtight, so I figure air goes in there by the lower pressure created by the "road draft" type tube under the car. That system works at the front of the car (for the engine), so should be OK for the battery too. Also acts as a drain if something silly happens to the electrolyte.