Trailer tongue box internal temps?

[DJWUZJ]

Figured the trailer gurus would have the best input here...

I'm working on my M416 build and purchased a trailer tongue box to serve as my hub for electronics. It is a thick poly carbonate, and will be water tight.

This will include:
1. ArcPak powered by remote 12v plug in from trailer hot lead
2. Separate blue sea hub with 60a thermal breaker between ArkPak and fuse block

This will fill all base camp power needs (lights, water pump, 110v, etc). I started to think about how hot it could get inside, especially if parked in the open sun, etc. ArkPak will function up to 122*F

Questions:
- has anyone had experience with what temps get up-to inside one of these?
- any solutions to help with ventilation while keeping it waterproof?

My solutions/precautions thus far include:
- marine fuel vent - allows pressure to escape and some excess head to roll out while keeping it weatherproof
- marine blower and vent - would be hard wired to 12v constant power, as well as fuse block with inline switch for when disconnected from trailer. Vent would face rearward between box and trailer body.

Will eventually post a build thread on this to keep update on progress... Just stockpiling parts for now!

Thanks in advance for any help!

Sent from my iPad using IH8MUD

 

[greentruck]

No personal experience. My tongue box is simply an open aluminum tray to hold our gas bottle. However, it's almost certain that a tongue box will exceed 122 degrees in the summertime any time it sits in the sun.

Does this item actually shutdown at 122 or is simply rated to work at up to 122 degrees?

I doubt that simple pressure relief solutions like marine vents will give you enough air movement to keep things cool.

A fan-assisted vent could work, but that devil will probably run constantly in some situations.

I guess I'm wondering why the box needs sealed so tightly? In my experience, better to arrange sufficient flow-thru venting, then make sure it doesn't allow moisture entry. It might pay to consider more significant venting, with a cover or other means to seal it tightly if you feel the need for that. One thing's certain. If you seal it up tightly, you'll eventually find you have internal condensation problems.

I'm also thinking your gear will operate above 122 degrees, so you may not have to go to the effort of trying to cool a box sitting in the sun to that temp at all times.

 

[DJWUZJ]

Thanks GreenTruck! You helped to confirm what I was thinking. I havent played with it yet, but my thoughts are that it will shut down at 122*F.... or at least I would hope so, since its so "smart".

As far as venting vs water tight, etc. My fear is that I dont want to get moisture into the unit that houses the $400 ArkPak, and all electronics. I know in an ideal scenario, the ArkPak would be outside of it, etc etc... but I think I have a solution...

They have 3" inline blowers for boats (bilges, engine bays, etc) that run on a 3A draw, and throw plenty of air. My idea is to have two vents on the backside of the unit... one for air to come in, and one for air to go out.

I'll have it run on a thermostat switch (on at 100, off at 85). I know that this could result in it running all the time, but at a 3A draw, constant power when connected to the truck, and switched power with the ArkPak, there is zero concern on the power side.

If the pumps can clear an engine room and keep the temp down, I'd like to think it would work for a 6-7sq ft box.

If anyone has another option, I'm all ears!

 

[ntsqd]

Those fans don't so much keep boat engine room temps down as they evacuate any explosive vapors that have built up. This is a crucial step prior to starting a gasoline powered boat with an enclosed engine room.

My inclination would be to not make the box water tight. Definitely make it so that rain isn't going to get in, but that can be done just with labyrinth seals. Then set up the fan(s) to pressurize the box. Have them draw thru at least a labyrinth filter (water and dirt don't go around 180° turns very well, particularly if the area is large so that the velocity is low) and maybe a small engine air filter as well. Make sure that there is enough exit opening to not work the fan motor(s) too hard, but make it tight enough to raise the air pressure inside of the box. I would put any exit holes low and intake holes high.

If air is rushing out of any gap, then dust and water will have a hard time getting in.

 

[greentruck]

A little clarification that may simplify the solution. Will this only be operating when parked, i.e. not running when traveling?

If so, that would greatly simplify the problem. Seal it up tight for travel, then vent it by opening up a door in an opening designed to exclude rain and dust as ntsqd suggested.

Don't forget what I mentioned about moisture. You will have overnight condensation sitting in the open in areas with high daytime humidity as the outside air cools around the container. unless it sealed up like a thermos. That's usually hard to do with wiring entry points, etc, so it's inevitable that you'll be getting moist air inside. The heat from the electronics will dry it fast with a little circulation, but might just stew in it if it's mostly sealed, but not enough to prevent air penetration.

I can see keeping moisture out and understand a desire to control dust, but ventilation is what keeps electronic cool and dry. If this thing is that fragile, does it really make sense to trundle it along to the great outdoors?