We have occasions to dry camp in our 5th wheel. I'd like to add a second battery to increase our run time before needing to fire up the generator.I'd like suggestions for a dual battery box with a sealing lid and single vent connection. I've done a little searching but only seem to find single battery boxes. I've seen dual boxes like this Todd 8D, high lid dual battery box but it doesn't have a vent hose fitting. I thought it might be possible to replace the vent in the lid with a hose fitting and adapt it. Aside from doing a mod like this, I haven't seen a commercially made box like I want.I know I could switch to AGM and use a non-vented battery box, but I'm thinking I can buy a dual box and another wet cell battery for less than the price of a single AGM.Thanks,KJ

I went to WalMart and got a plastic tub with locking top. Drilled a hole in the top to put my OEM vent hose through, put stainless steel worm gear hose clamps on both sides of the hose to secure it to the top. Wallowed a relief with a half round file on the tub top edge until the battery cables would clear the lid, and the lid would latch. Drilled a couple .250" holes about 6" up from the bottom of the tub to provide an air inlet. Throw the batteries in the tub. Used some treated 2x4 to sorta keep the batteries from sliding around. Rock and roll. Rednecked the heck out of it. .

1. I took the original box and cut the hose connector off the top, cutting about 1 inch wider to make a flange. Same on bottom. Sharp utility knife worked well...just don't cut yourself.2. Using a hole saw I cut a hole on the top and the bottom of the new box.3. Mounted the hose flange on the inside of the new box sticking out. I used black RTV to seal on the bottom and Black RTV and a couple of small bolts for extra strength on the top lid.4. Self tapping screws for the mounting lugs on the corner of the new box.5. I sealed the lid with some foam strips..the kind used to seal a home window ACHere is a link to the box I used.NOCO dual 6 volt box

Better price for NOCO dual 6v boxAnd I did it the same way LearJet did it or he did it the same way I did. LOL!

Okay, then I'm not crazy.....well at least about this subject. Not that I've searched to the ends of the earth, but the little bit of looking I have done turned up ZERO hits on dual battery, sealed boxes.The mods to the NOCO dual box is exactly what I thought would be necessary. Looks like I'll make plans to go that route.Thanks a bunch.KJ

I've got that same NOCO HM-426 box.It is not necessary for the box to be sealed. Unless you run some kind of glands around the battery cables, there is no way you are going to get it sealed. More importantly, sealing it is not necessary.My dealer did not bother to install the vent hose. I ran it that way for a couple of years, and it caused no issue at all. I finally got tired of it just bouncing around, so I connected it. All I did was figure out a hole size, and then screwed the corrugated hose right into the hole. No fitting necessary.

Dual Battery Box with single vent | Good Sam Community

bpounds
Nomad
Dec 21, 2016
LIKE2BUILD wrote:
However, it seems like everyone is really proud of them as the cheapest I can find is about $130. At that price I can almost buy the cheaper NOCO box for 6V batteries, get 2 new golf cart batteries, and wire them in series.

KJ

Yep! I like the way you're thinking. If you're going off-grid, 6V is the way to go.
LIKE2BUILD
Explorer
Dec 21, 2016
bpounds wrote:
Do your homework when selecting a box. 6V are a little taller than most 12V. Can be a problem with some 12V boxes around 6V batts. OP did not say what batteries he has, but 6V won't fit in the box linked a couple posts above.

I currently have a single Group 27 battery. The intention was to get a second Group 27 and run them in parallel.

It looks like this Quick Cable QuickBox Dual 27/31 battery Box is about the best fit.

However, it seems like everyone is really proud of them as the cheapest I can find is about $130. At that price I can almost buy the cheaper NOCO box for 6V batteries, get 2 new golf cart batteries, and wire them in series.

KJ
bpounds
Nomad
Dec 21, 2016
Do your homework when selecting a box. 6V are a little taller than most 12V. Can be a problem with some 12V boxes around 6V batts. OP did not say what batteries he has, but 6V won't fit in the box linked a couple posts above. (Well, since he's got 1 and is adding a 2nd, obviously he has 12V )

Regarding the question about why to use boxes, I agree that ventilation is an issue, but more important I think is collecting spills and condensates. The boxes need to have leak proof bottoms. We've all seen what happens to the battery trays in vehicles over time. Tops don't need to be sealed. Bottoms should be.
Pipeman
Explorer
Dec 21, 2016
I called my dealer when I got a bigger set of batteries to see if they had something like what my old battery boxes had. Much to my surprise they had adapters that I bought. I cut the holes in the top of the new battery boxes, fitted the adapters and the hoses that were there for the old batteries were used on the new battery boxes. Might help to give a dealer a call.
lakeside013104
Explorer
Dec 21, 2016
jsiemers wrote:
If you are looking for a dual battery box for 2-12 volt batteries, try this web site: http://www.batterymart.com/p-120215-quickcable-dual-27-31-battery-box.html. A dual battery box for 6 volt batteries is smaller.

Link for post above

Lakeside
jsiemers
Explorer
Dec 21, 2016
If you are looking for a dual battery box for 2-12 volt batteries, try this web site: http://www.batterymart.com/p-120215-quickcable-dual-27-31-battery-box.html. A dual battery box for 6 volt batteries is smaller.
Me_Again
Explorer III
Dec 21, 2016
Ventilated vs non ventilated compartments. Chris
azdryheat
Explorer
Dec 20, 2016
Not sure the reason for the battery box. A requirement? Is there something different on the Class A's that have many batteries and none in a box?
Learjet
Explorer
Dec 20, 2016
yep, you think some one would make a dual sealed box.
bpounds
Nomad
Dec 20, 2016
I've got that same NOCO HM-426 box.

It is not necessary for the box to be sealed. Unless you run some kind of glands around the battery cables, there is no way you are going to get it sealed. More importantly, sealing it is not necessary.

My dealer did not bother to install the vent hose. I ran it that way for a couple of years, and it caused no issue at all. I finally got tired of it just bouncing around, so I connected it. All I did was figure out a hole size, and then screwed the corrugated hose right into the hole. No fitting necessary.