How to mitigate truck box condensation


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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?


Approved Vendor : Total Composites
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.


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



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.


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.

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