I got into a discussion recently that got me thinking about a few things and I want some group thoughts.In my TT (in sig below) I have a full pass-through compartment, then a compartment for 2 LP bottles. There is only enough room on the hitch for one battery and in fact the dealer had to redesign the hitch to move the battery from the factory location to accommodate my WD setup. I have contemplated increasing battery potential but the conundrum of where and how to mount several batteries comes up. I have considered a 4 battery box on the rear bumper but then I have to relocate my spare and possibly remove the outdoor grill mount.Then I came to a realization. I have considerable space in the storage compartment under the bed. Would it be possible to create a 4 battery space under there that would have enough ventilation to be safe? Granted the potential for a battery fire is always present if something should go wrong but most of us have a battery right next to the LP tanks which in my opinion is just as, if not more, dangerous. I suppose one could sacrifice part of the pass-through and put in a slide out battery tray for batteries and move some gear into the bed storage but it seems to me that in the interest of regular access the batteries don't need to be accessed and would be more out of the way under the bed.Damn engineering background is always forcing me to solve these questions even if I never implement them.

possibly AGMs or whatever they are called.bumpy

Here is how I worked around the situationThe built post is herePutz

Phenrichs, the problem is the outgassing of Hydrogen gas during charging. Thus the need for good ventilation. The battery being mounted in proximity to the LP tank, in an outdoors environment, does not present an enormous hazard.It is entirely possible to mount extra batteries "under the bed" in a box with ventilation to the outside. Here is box that I use and the ventilation method I chose. The white hose is the box vent. Photo #1 is the box with two 6V CG2 Batteries.Photo #2 is the outside vent from the battery box

Without pictures of the spaces mentioned it's difficult to offer good advice but here goes: If you have one battery on the tongue, there should be enough space to mount more than one. The narrow boxes like Pondputz built accommodate this. Installing batteries in a hatch compartment is certainly doable and I wouldn't worry about fire as long as all the connections are secure. Ask yourself if you have ever seen the results of a battery fire or have you ever read about one. Years ago, I had an old Chrysler wagon that had a loose terminal connection (worn out battery post). I decided a screw turned between the (+) post and the connector was a good idea. What I didn't calculate was the height of the screw. When I finished my professional installation and closed the hood, the hood rested on the screw. Later, I saw a black spot on the hood and opened it to find that the battery had shorted and blown the top of the case completely off. If there was ever a chance for a battery fire that was one. I would be concerned with is hydrogen gas ventilation and a couple of well placed vents should take care of that. Good luck with your batteries.

If you use a 120vac muffin fan to exhaust (ventilate) the area under the bed it will keep hydrogen, hydrogen sulfide gasses to an acceptable level. Cover the top of the batteries to keep Pb (lead) and it's sulphates from migrating. Servicing the batteries may pose a problem. Absorbed glass mat would be a viable option.

Battery Box planning wisdom needed (kinda long)

23 Replies

down_home
Explorer II
May 15, 2013
I installed a second battery in our Alumiscape Fifth wheel. Factory sent the second box, like some Boat boxes with a cover and vent tube and tie down. Both were vented to outside with clear tubing and a hole in the bottom of fifth wheel. It was sealed around the edges. Just had to be sure that no pressure was generated into the tube. I was somewhat concerned about acid vapors damaging some surface and then the underlying material under it. Never had a problem that I remember.
Learjet
Explorer
May 15, 2013
QuickCable, strong box and I put the switch on it.
fosstugz
Explorer
May 14, 2013
Learjet wrote:
here is what I did:

LearJet, what kind of box is this and did it come with the switch on it installed already?
69_Avion
Explorer
May 13, 2013
As shown most folks would put extra batteries on the tongue. That is the best place for them if you can fit them there. Remember, they can be side to side, or with the right mount, they can even be stacked.
DarthMuffin
Explorer
May 13, 2013
I just did exactly what you were thinking. I got a 4 GC2 battery box, mounted it under our bed and installed 4 6V AGM Batteries. The batteries weren't cheap! I spent about $1000 on batteries and didn't even get a "Cadillac" brand. Hopefully they will last us a good long time though. I did have to route some 4GA welding cable through to the converter -- went down through the floor, over to side, along to rear of trailer and back up. About a 15 foot run.

AGM was the only way I would consider mounting batteries indoors, especially when the logistics of my situation prevented a "high" vent to get some convection going through there. Also my underbed box was just in front of the axle so it helped the weight distribution of our trailer.
crcr
Explorer
May 12, 2013
I have a Rockwood Mini-Lite TT, upgraded from one 12V to to 6V GC batteries. The box I used is 3/16" PVC, nice HD construction. Two 6V GC batteries just shoe horn into it, as designed. Then I built a locking hold down for it as you can see.

My OEM battery tray just held the box, but with the taller 6V batteries, the batteries were too tall -- were bumping the front of the TT, so I cut the tray out and re-welded it 1.5" forward. I bought the battery box here, and they have them to fit 12V batteries also

image hosting no registration
pondputz
Explorer
May 11, 2013
Do you have a lid or top for this? I like it...

Here is a picture of it finished.
I apologize for the dark photo it was dark when I finished it

I used button head (allen head stainless machine screws for the assembly)

The blue and red Anderson Connectors are for the solar and wind charger connections

Putz
Learjet
Explorer
May 11, 2013
here is what I did:
RoyB
Explorer II
May 10, 2013
I thought this post sounded familiar - we have all discussed this same situation before back in APRIL last year. Guess you didnt make any headway...

Roy Ken
RoyB
Explorer II
May 10, 2013
I'm thinking if it has enough room for ONE BATTERY on top of the tongue you should be able to mount angle strips and add at least two more batteries extending out both sides???? The angle strips would have to be strong enough to support the weight of a battery. If the battery is recessed down inside the two trailer tongue sides then that would be a whole different story...

Roy Ken