How to mitigate truck box condensation

[sigo]

I’m looking to see how other people mitigate condensation in on-vehicle storage boxes. I decided to try a Pelican cargo case as a storage box in the bed of my truck, and as expected the condensation that builds up is horrible. Everything rusts and molds unless I constantly attend to it. The last box I tried was a standard aluminum truck box that was painted black, same results. The box before that was unpainted aluminum and wasn’t terrible, but the lid didn’t fit tight so it breathed better. But that was a trade-off because in the winter snow would get up under the lid and collect in the box. When it melted or when rain got under the lid it seemed like it would never dry out.

I’ve dealt with this issue in Georgia and now in Kansas. It almost seem worse here in KS due to greater temperature swings. This was never an issue when I lived in Alaska.

Any good solutions out there? Desiccant is not an option as it requires constant replacement/recharging. Does anyone sell a weatherproof vent I can install to allow air exchange and to keep the air temp inside the box closer to ambient?

 

[Victorian]

It’s a common issue rarely mentioned! Thank you for bringing it up. Not too long ago someone mentioned the exact same but with huge diesel fuel tanks on Expedition trucks. Not sure what the solution to your exact situation may be but I have decided to construct my under mount storage boxes on my expo truck out of insulated panels.

 

[rruff]

Drill a hole and put something like this over it? Marine vent cover.

 

[Victorian]

Drill a hole and put something like this over it? Marine vent cover.

A vent + a fan would help . Question remains: How is moisture getting in the first place? Without water, there is nothing to condensate.

 

[rruff]

I could be wrong, but if the box is sealed and you close it when it's warm... and then the temperature drops below the dew point in the box... maybe. If that is the case I don't think much ventilation would be needed.

 

[IdaSHO]

Here in the snowy PNW, its a common issue.
Enough that most truckers avoid it by drilling drain holes in boxes and toss rubber mats in the floor to keep straps/gear off the floor.

Moisture typically is introduced by wet gear. Beyond that its a matter of relative humidity and temp swings.

Personally, I treat these boxes as "outside" gear stowage only, and provide drains, expecting them to have moisture in them.
Best solution in this case is to allow moisture to escape. It as close to an uphill battle as you will fight if you try to treat them as dry storage compartments.

 

[Ozarker]

Is moving back to Alaska an option?

 

[tirod3]

It's a universal problem caused by humidity in the air for the most part. Air temps changing from warm to cold cause containers to condense moisture on surfaces. it runs down and collects. When you see dew on the outside of the vehicle, there can be a lot more hiding in the panels, etc., and fitted containers are the worst, sucking in moist air but not drying out.

As above, best you can do is drill holes to breathe and drain. Poly molded containers do it less - not as much mass/density. In the days of distributors, it was the tightly fitted caps that would wet out and cause morning running issues until engine heat dried them out. We would actually drill a small hole in them to stop it. Same with headlight assemblies now. What fixes it is ventilation.

 

[JaSAn]

Silica gel (those little bead packets that come with electronics). It's used in gun safes to absorb moisture. Stores that sell guns (photography, crafts) should have it in bulk.
There are on line calculators for how much you need based on volume.

Can be dried and reused for a long time. The less air exchange with outside the longer you can go before needing to dry it out; they change color when saturated.

 

[Kors Camps]

I live in the pacific northwest where everything's wet all the time 9 months out of the year. I think the reason my roof boxes stay dry and mold free is because there's enough ventilation aided by the air that's forced through while driving. It circulates into the bottom at the box's mounting points and through the seem around the boxes lid.

The moisture that does build up on a wet tent or a snowboard for example needs an opportunity to escape via evaporating while the boxes are exposed to sun light. 6 years now & I don't experience mold or rust issues with the tools & gear that live in storage boxes year-round.

The way I see it we're just camping, we aren't operating in a combat zone. I think some of the popular storage boxes are way overbuilt for the job, to a fault. Think water/dust proof, not water/dust tight.

Inno Roof Box and Aluminum tool box




Suggestions

1. If i had a storage setup that wasn't exposed to air movement or sun light, I'd install super efficient computer fans and power them off my deep cycle battery or a cheap, small solar panel. Or;
2. Headlight retrofit retailers stock one-way gore-tex breather patches and thread-in one way breather valves used to prevent moisture from accumulating inside of headlight housings. This might be a viable passive solution for you. In fact I might even use a few of those patches to vent my awning cover!