It's that time of the year again..condensation.

**Hectic** · 04-03-2012, 05:05 AM

Well i'm going on about 2 years running my painstakingly configured desktop rig in the trunk. Custom wood and acrylic case finished off with charcoal carpet, based on an old ATX chassis. Very cool case if I must say

98% of the time this beast boots up from hibernation in 14 seconds and runs better than my home computer.

The other 2% of the time, are on days like today. Cold nights that turn into sunny mornings. My trunk turns into a virtual greenhouse. The DSATX will usually supply power to the motherboard but it will fail to POST until the condensation is fully evaped via system fans. Today the DSATX wouldn't even turn on and I had to sit there with the trunk open to let it air out naturally. After 20 minutes the PSU would supply power, and went through the system drying routine. When all looked ok visually I hit the reset button and the computer booted up from hibernation as usual.

Obviously this needs to stop for countless reasons. While designing the whole thing, I had an exhaust system in mind using cabin air, but kind of put that on the back burner. Even if I hadn't, the computer would still be subjected to condensation when parked and I would still be forced to dry it out while driving on days like today, risking god knows what on power up.

What I really need is some sort of humidity sensor and relay that will kick on my auxiliary exhaust system when the humidity inside the case reaches a certain point. Or at the very least some sort of desiccant in the enclosure itself to prevent condensation from building up in the first place (which I did intend on including in the case during the build). The latter would probably be the easiest, but probably not as reliable as an automated exhaust system that nips the condensation in the bud if it begins to collect when the car is parked.

Can anyone please recommend some sort of humidity sensor/relay device that I can use to turn on aux. fans automatically? Google and ebay don't show me much with the keywords I'm choosing..

**malcom2073** · 04-03-2012, 07:46 AM

Condensation happens when warm moist air meets a cold surface. What would happen if you bring more warm air in? More moisture, until the temperature of the surface equalizes and evaporation begins. That's sort of odd that your trunk is getting so much humid air. I get zero condensation on my amplifier which is in the trunk, nor on my carpc which is in the cabin. Perhaps there is some other reason you are getting so much humid air in the trunk that you should look into? Bad seals, and rotted pressure equalizer flap, or maybe just a hole somewhere?

**Sonicxtacy02** · 04-03-2012, 08:07 AM

Yea i've never had any problems with condensation, despite my many attempts to crudely force cold air into the trunk lol. Where do you live Hectic?

**Hectic** · 04-03-2012, 10:22 PM

Ideally I'd run the outside air opposed to the cabin air, but that's a new ball game. I suppose it makes sense that recirculating the warm cabin air might not solve anything, although the cabin seems to be drier air than the trunk during these times, and I have no doubt that if the PC were located in the cabin, I wouldn't have this problem. There are some places on the car that are definitely not air tight, for example the spoiler holes which I patched a few years ago, although the trunk seals are in good shape, I don't think that's the problem.

I live in Portland, OR, so that plays a big factor. It's one of the wettest, greenest places in the country. Weather changes on a dime. Rain, sun, snow, hail, everything. For example two weeks ago we woke up to 2 inches of snow on the ground, by 5 PM it was sunny and dry with no trace of the snow or even water on the ground.

I should probably go ahead with the desiccant units in the case. If it fails to keep the condensation away from my components I'll move on to the humidistat idea.