Replacement Battery Box?

[LisaLisaRVA]

Hi everyone- long time lurker, first time poster. I've combed the forums and haven't found an answer so hopefully someone can help me out with this problem!

We're attacking the second to last major project on my 2009 Flying Cloud 23FB. There was some surface ruse on the tongue and on the battery box. We've stripped everything off and discovered that the battery box was a few miles away from completely falling apart. The batteries were mostly supported by the plastic tray inside and the bottom was completely rusted out and separating from the sides.

Airstream only sells metal replacement battery boxes. For reasons I don't entirely understand as anywhere else in the world you wouldn't store batteries in a metal box. We've cut out the box (what a pain) and are searching for a suitable replacement that hangs below the tongue as opposed to sitting on top of the frame.

Has anyone made this replacement/repair with a plastic battery box- if so which one did you use? I'm sticking with the lead-acid batteries for now (upgrading to Lithium/new inverter/solar is the final big project and still a couple years down the pike).

Interested to hear what folks experience with this has been. Alternately I'm considering having an aluminum box made so at least it won't rust but prefer a rugged plastic solution instead.

Thanks

[GetawA-S]

LisaLisaRVA,
Like you, I was appalled by the inefficient use of space with a battery box that pokes up above the frame on my 22 Sport and previous SOB's. I assume that's how it was on your '09 FC 23 FB. I was thrilled to see the flush design (other than the projecting latch, now replaced with a flush key latch) when the wife had me look at a 2020 FC 23 FB. I also appreciate the essentially sealed AGM's that came with it. It's the corrosive vapors that destroy the battery housing.
Aluminum is not as corrosion proof as people think. Element 13 is very reactive, which is why it is never found in pure form in nature. Look into the thermite reaction. Its thin coating of aluminum oxide makes it stable under most conditions, but NaOH, chlorides and airborne sulfates will eat through the thin oxidized coating and cause structural failures. (I had to deal with aluminum sulfate raining down from the ductwork when I worked at a corn wet milling plant 40 years ago.) In addition, it's tricky to weld aluminum to a steel trailer frame.
A well chosen plastic is chemically stable, but very prone to fatigue failure. Batteries are heavy, and the roads are bad!
Finally, it is often not cost effective to engineer a solution to a problem that experienced designers have addressed with a suitably thick structure of an inexpensive material. (A sturdy steel box is easily purchased for not a lot of $.)
Your previous box lasted for almost 15 years. My recommendation would be to emulate an up to date battery box, mount it to suit, and set batteries that don't vent corrosive gases on a plastic tray inside. Make sure the box is vented, well painted and refreshed with WD 40 (water displacement formula 40) on a regular basis, and get on with your enjoyment of the camping life.

[GetawA-S]

The nighttime rehashing of years past reminded me that my failing ductwork from 40 years ago was galvanized steel, producing zinc sulfate. Regardless, sulfuric acid is rough on aluminum, though not as rough as hydrochloric acid. There is even a product called Alumabrite, similar to the concept of the old Naval Jelly (phosphoric acid), that allows amateurs to try their hand at pickling clean their metal surfaces. Results may vary.
I just needed to clarify that before the astute posters on this forum questioned my answer.

[Wazbro]

Every car and truck I took a battery out of the battery was mounted onto a metal tray, no plastic under it. You should just use a metal battery box and clean it up then repaint it at least every time you replace the batteries.

[LisaLisaRVA]

Thanks for the response. My batteries were actually in a metal box that was welded flush with the frame so space inefficiency wasn't a problem. Its been removed now and we'll sort out a solution that doesn't involve another metal box (my preference) that's going to slowly rust away like its predecessor. My partner spent his career in the marine industry which relies on rugged plastic battery boxes so we're going to start looking there. Will be sure to update here once we complete the project.

[onemorejeff]

You could fab up a custom fibreglass one and bolt it to the frame

[rmkrum]

My current setup is two pieces of 1 1/4” angle iron spanning the A-frame at the bottom edge and supporting the long edges of a heavy duty aftermarket plastic battery box that holds two GC-2 golf cart batteries narrow side to narrow side. Stainless steel bolts hold the box to the angle iron and there are 3/8” drain holes in the bottom of the box. I use a nylon self-locking strap to hold the lid on at the moment. Planning a better lock mechanism.

It does stick up above the A-frame a bit but works for my needs. Here’s a picture from a bit to the side and forward of the installed box.



A clever welder could hang the support frame quite a bit lower.

This setup survived a major acid spill from a badly boiled out set of flooded lead acid batteries.

It took two pounds of baking soda and a couple gallons of water to safely neutralize the spilled acid.

The only damage was to the old non-stainless fasteners holding the box in place (since replaced) and the ends of the OEM battery cables, also were planned to be replaced.

Only real long term damage was to my budget from replacing the batteries prematurely. Sigh.

New battery cutoff switch on the new cables.

[GetawA-S]

LisaLisaRVA,
It is great to know someone with fabrication or procurement skills to get what you want.
I regularly drive north on I95 towards a restaurant called “South of the Border”. Their billboards are quite nostalgic. OK, they are just offensive, but one of them reads, “The road is bad, but Pepe will fix!” Your a-frame bounces/jars much HARDER than a boat. Consider a belt and suspenders approach, such as Rich describes: a sturdy frame with a storage box set on top and bolted or lashed in place with distributed contact (big ol’ washers).
Good luck!

[Silvr_Bullet]

I have upgraded my single AGM to lithiums, they’re housed in a plastic Camco box that sits above the A frame. I remove my batteries in the winter months, it’s removed box and all, the weight is approximately 60 pounds. The old box serves as temporary housing for all the wires that attach to the batteries. The plastic is easily replaceable, inexpensive and black.

[LisaLisaRVA]

Belated update to my battery box saga.

Ended up getting the box replicated by a local metal shop- instead of welding it back in we used bolts into the cross bars on the frame for easier removal and replacement in the future. Also added more drainage holes in the bottom so it won't rust out as quickly. Fortunately we were able to reuse the original lid and save some money there. Happily it looks exactly the same- just need to match the paint on the lid to the color matched paint we used when touching up the frame.

Thanks for all the feedback, happy towing!

[LisaLisaRVA]

Oh and I don't recommend painters tape on the chrome- we used name brand 3M painters tape to block off the trim and body and it peeled the chrome off the trim !

[FLCoast]

Just curious, was/is there a reason not to store the batteries in the same boxes that a lot of small craft store their batteries in? The black boxes with lids usually held down by a 1 to 2 inch wide strap. They have to be used in conjunction with a structure strong enough to support the batteries - like the metal box- but usually work pretty well for containing the batteries, spills,… just curious.

[LisaLisaRVA]

It came down to aesthetics. I wanted a battery box that would hang below the frame, like the original and not sit on top of it. I couldn't find a rigid plastic/boat style box that had the correct dimensions.