Controller fans

[Jandrews755]

I'm after some advice on how many fans to install on my main controller box. I have a falcon v3 and 2 power supplys. Being in Vic it will get fairly hot over December so do I need 1 fan or 2 ( 1 sucking 1 blowing to keep air curculating) thanks

 

[abundy]

If the last 2 decembers are anything to go by, water protection will be more important.
As Kate said one fan will do.

 

[David_AVD]

One fan is fine (as exhaust), but make sure you have a second vent for an air intake. Without the inlet there will be no air flow.

 

[djgra79]

Sorry to drag up an old thread but I heard some conflicting advice from this year's Mini that I'd like to clarify/discuss with the group.
I've always followed the above advice of using a fan to pull air out of the enclosure and a vent to get the air sucked in from the fan pulling out.
But at the mini I was told that a fan pushing air in is better to stop any moisture building in the enclosure. Seems somewhat valid but wondered what others do and if there is a "correct" way or so long as there is some type of air flow it doesn't really matter?

 

[Skymaster]

You've just opened the can of worms that is the #1 debate in all computer enthusiast case design.

Air is getting getting forced in by the intake fan, or being passively sucked in by the exhaust fan.
I don't think moisture would play a part, as the same air is getting in one way or another.

The #1 question is what air is needed where.
Are you trying to remove the hot air out of the enclosure from where it is directly generated, or are you trying to blow cold air on a specific component to keep that component cool, and don't care where the hot air ends up as long as it eventually makes its way out.
The former, exhaust fan. The latter, intake fan.

The air you're bringing in isn't exactly cool being outdoors in an Aussie summer. Given the PSUs generate very specific heat at a very specific location, and realistically that's the main reason you have a fan in your box. For that reason I am in the exhaust camp. With cross flow so that the intake vent is on the opposite corner of the box.

 

[Katekate]

it really doesnt matter if the fan is on the inlet or the outlet, the air will flow the same.

something else to consider is how other fans in your enclosure affect airflow. I use hp server power supplies and they blow from the dc output side to the ac inlet side (from inside the server to outside in normal use) I always try to orient them so they blow towards the top of the enclosure.

 

[Pavle]

The obvious caveat once you add any vent to a sealed enclosure is water ingress so I mostly focus on that consideration over any other heat technicality.
It's certainly an area that seems to be over complicated and simply exhausting the heat generated by your electronics to me is the main goal whilst ensuring no water will run in.

Interestingly, I have 2 x 90A 5v MW PSUs in the latest box I have built. I powered it up and closed up the box with a digital thermometer inside the case and I didn't see the temp rise above 35 degrees under a smallish load of about 200 pixels at 100% - granted it's not in the heat of summer yet here in Sydney with the ambient temp about 23 degrees and it's also not loaded up. I will still throw a exhaust in once I receive a vent delivery plus a small intake that is a fanless vent.

 

[scamper]

I don't have fans in mine. But I will point out that my enclosures are large and have vents in the top and bottom well and truly large enough to have a good air flow.
The fans in the power supplies will cool them directly and as hot air rises (or more accurately, cold air pushes hot air up) Physics will do it's thing.

What Kate says is very pertinent, you must make sure that you are not trying to force air opposite to an existing fan otherwise you will make the cooling effect worse and not better.

 

[Skymaster]

Convection is a perfectly valid method of cooling, especially in a large case. My master control box has 1.7kW of pixel power PSUs and another 300W computer PSU in it to power the controllers & Pi, plus a network swtich and a bunch of other 240V control kit and it just relies on it's natural ventilation built into the roof of the box.

Two of my main control boxes were out in the elements last year, both with 2x 60mm vents from David

- One with a fan and the other passive - no issues with water ingress whatsoever.

 

[Whitey-]

Convection is a perfectly valid method of cooling, especially in a large case. My master control box has 1.7kW of pixel power PSUs and another 300W computer PSU in it to power the controllers & Pi, plus a network swtich and a bunch of other 240V control kit and it just relies on it's natural ventilation built into the roof of the box.

Two of my main control boxes were out in the elements last year, both with 2x 60mm vents from David

- One with a fan and the other passive - no issues with water ingress whatsoever.

Hey @Skymaster , any chance you can post a photo from a couple of angles showing how you've installed these?

I've bought some, along with some mesh and fans and I'm assessing methods of installation currently.

 

[Skymaster]

This is my megatree box. It gets the most heat and rain exposure sitting under the MT, pretty much out in the open.
The other one lives under the hedge so is shaded both sun and water by the bushes above it.


Shrouds on the outside of the box. Only the one on the right has a fan in it.



Overall layout internally


Left side - passive vent. The black thing and cables are for a temperaure sensor



Right side - active fan, exhausing air.

 

[Whitey-]

Thank you! I'm working out my controller box as I go, and it's a relief to see what I suspected was a valid approach. Ok great.

I also was about to post here asking about stacking connections from the power supply to the fuse block - looks like you've answered that one! I've got 25A rated 2mm cable I wanted to stack and try and equally distribute to the block with.