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View Full Version : What kind of fans to put in a hood?


agoutihead
08/15/2007, 08:47 PM
What are the cheapest fans to get to put in a hood?

Ideally I would like to wire them together so there is only 1 plug and they work simultaneously.

I need one for an out, and one for an in.

scubajsm
08/15/2007, 09:22 PM
I used the coralife, I wouldn't say they were cheap.

thejamesvolta
08/15/2007, 09:30 PM
Try a PC fan. That's what I plan on using.

PC Fans (http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=2010110573+1372726538&name=120mm)

agoutihead
08/15/2007, 09:36 PM
How well do they actually hold up? But these are meant to be plugged into a motherboard, so what do you do, splice a plug on he end of it?

Those should be easy to splice together shouldn't they?

Just match up the colors and it sould power both fans at the same time right?

thejamesvolta
08/15/2007, 10:33 PM
You would probably need some sort of trasnformer I believe, because the fan runs on 12v. Here is the only way I know how to do it. I'm sure there's a better.

PSU Paperclic Trick (http://aphnetworks.com/tutorials/psu_paperclip_trick)

adnup
08/16/2007, 12:59 AM
I use 2 radio shack computer fans. I think they are just wired to a cord and plugged direct to the outlet...no transformer...

D.Blaine
08/16/2007, 01:04 AM
I bought 4 PC fans (120 mm- total power draw is about 34 ma) then cut off all of the 4- pin molex connectors exposing bare wires. Next go to radio shack and get a small DC adapter the one I picked up was 500 ma for about 12 bucks, splice all fans together and splice with DC adapter.

total setup cost me about $25 I have over 600 watts of MH and T-5 and my tank never gets over 81 degrees in the summer here.( by the way I don't run a chiller.

Pmolan
08/16/2007, 05:47 PM
PC Fans
http://i162.photobucket.com/albums/t251/pmolan/DSC05521.jpg

Hard Drive Fans on Ballasts.
http://i162.photobucket.com/albums/t251/pmolan/DSC05520.jpg

Component Fans
http://i162.photobucket.com/albums/t251/pmolan/mesh3.jpg

PC Power Supply
http://i162.photobucket.com/albums/t251/pmolan/DSC05519.jpg

Rouselb
08/16/2007, 08:06 PM
wow...i use a couple of desktop fans..cheap, and work great, they are hooked to my AC JR. Temp stays nice at 81! htt

Rouselb
08/16/2007, 08:07 PM
http://reefcentral.com/gallery/data/500/140601DSC00481.jpg

AZDesertRat
08/16/2007, 08:25 PM
Two Vantec Stealth 120mm (4 inch) fans both blowing in with a $5 variable voltage power supply. Fans are like $12 each at Newegg and are totally silent especially when running at 9.0 or 10.5 volts in the winter. Make them both blow in or you are wasting one fan. You only get the CFM of a single fan with one in one out while you get two full fans volume if they both blow in. Blowing in also draws cooler dry air across the fan and blowing out draws hot damp air and shortens the fan life significantly. Been there done that.

agoutihead
08/16/2007, 09:26 PM
Yeah I do want them to be sillent, so those stealth fans sound like a good idea.

You think both in huh? I would assume one fan blowing in and one fan sucking out would keep the temp inside more consistant. So where is all of that hot air going to go while it's inside?

Sure it will blow itself out eventually, but it doesn't seem like a high enough air exchange compared to an in/out setup?

bigginapk
08/16/2007, 09:41 PM
I wonder the same as agoutihead because that is what I planned to do to my hood !! One in and one out !! That makes alot more sence to me !! because it will draw the hot air out and cool air in !!

AZDesertRat
08/16/2007, 10:19 PM
You can stack 100 fans in a row but the last fan is only going to move what the one before it feeds to it. Its like pumping water up a hill and having to put booster pumps along the way to get it to the top, they will each only move what the one below it pumps up to it.
By having both blow in, in the case of Vantec Stealths thats 53 CFM each you get 106 CFM in. If you have equal size or larger holes in the top or high up in the back you don't get much resistance to air flow and you also take advantage or convection.
I have tried every combination imaginable over the last 15 years and it really makes a difference.

agoutihead
08/17/2007, 07:17 AM
So your saying put the two fans in, and just drill/cut out exit holes?

SaltyDr
08/17/2007, 07:48 AM
You could cut out exit holes (top or opposite side as fans), but there might be enough area along the back.

AZDesertRat
08/17/2007, 09:58 AM
You want the exit holes to be as high as possible to take advantage of convection.

einsteins
08/17/2007, 10:08 AM
I got mine at grainger
They carry AC models that you could easily wire together and they are soo much better made than pc fans.

eins

AZDesertRat
08/17/2007, 10:17 AM
I have yet to find an AC fan as quiet as DC computer fans. Every one I tried without exception was noisey. Also you cannot easily vary the speed of AC fans like you can with a DC fan. Food for thought.
Wiring up DC fans is no more complicated than AC, 2 wires, a red and a black are all that is needed.

agoutihead
08/17/2007, 11:46 AM
Well My tank is only a 40 breeder, and I don't want alot of evaporation, so maybe I should get 2 fans smaller than 120mm?

I will drill 4 - 1" holes at the top, that should be plenty of exits to give it good convection shouldn't it?

AZDesertRat
08/17/2007, 12:31 PM
120mm fans are usually quieter since they can run at lower RPMs. You can also slow the 120mm fans down further with a $5 variable voltage power supply thereby reducing the CFM and evaporation.
4- 1" holes will not give you anywhere near the surface area of a single 4" hole or even a couple of 2" or 3" holes. If my math is right it would take 16- 1" holes to equal the surface area of a single 4" (120mm) fan. You want at least equal surface area or you create back pressure and move much less air due to resistance.

TWallace
08/17/2007, 12:37 PM
I got 4 120mm fans (http://coolerguys.com/840556026129.html) for my hood over my 55g. The reason you want 120mm is they move more air while also being quieter than the smaller ones that run at higher velocity. If you want smaller fans, make sure to find the noise rating of the fan. Try to stay under 25db if possible. If you don't want 120mm due to the size, I'd go for 80mm.

You can hook them up to a variable voltage DC plug. I got one from Radio Shack that's 3-12v. Lowering this switch will decrease fan velocity (and noise).

You'll need to splice the cords for both the DC adapter and the fans and wire them together. You'll likely have an extra (blue, I think) wire from the fan that isn't used. It's used by motherboards to control fan speed. The fans will have an amperage rating. The DC adapter will also have an amperage rating, usually between 600 and 1000 milliamps. You can hook multiple fans up to one DC adapter, provided the amperage requirements of the fans combined do not add up to more than the DC adapter supplies. Try to make sure the adapter provides more amperage than is needed by the fans. On the fans, the amperage may be listed as a decimal, like .12 Amps. This is the same as 120 milliamps.

I'd use wire nuts and electrical tape to connect the wires. Make sure they don't hang down into a place where water can drip down the cord. There's probably safer ways to connect wires in situations where water is nearby, though.

AZDesertRat
08/17/2007, 12:40 PM
Connect them with butt splice (crimp) connectors and shrink tube for a good tight water resistant splice. The odd wire is usually yellow on the Vantecs, you just ignore it and use the red and black wires. I always do a temp splice first to ensure the fans have the right rotation, ie blowing in and not out, before I make the permanent splice.

agoutihead
08/17/2007, 12:48 PM
So your saying cut 2 - 4" holes in the back and that should stop any back pressure?

If I put the fans on the right and the left on the bottom, should I then put the exit holes at the top left and right, or the top middle?

Which is more effective, or it really doesnt matter?

AZDesertRat
08/17/2007, 03:09 PM
I would put them closer to the middle so the air has to travel at least half way across the tank and lights before exiting.

agoutihead
09/01/2007, 10:49 PM
Ok I'm about to build my hood and need to figure out exactly what I'm going to do.

do you think 1 fan in the middle of my 36" 40 breeder is enough? Or one on each side would be better?

I checked new egg for vantec, and I couldn't find any stealth, just the following...

http://www.newegg.com/Product/Product.aspx?Item=N82E16811999614

http://www.newegg.com/Product/Product.aspx?Item=N82E16835110014

The first one has a dba noise level of 28, and the second one has a noise level of 29-39, so the first one is quieter right?

And it's cheaper too.

But are the stealth ones quieter than 28 dba?

Where do I find one of these $5 variable voltage power supplies?

AZDesertRat
09/02/2007, 02:26 PM
The first ones the SF are Stealths, the second ones are Thermo flows. Power supplies can be found at Radio Shack, WalMart or Frys Electronics. I got all of mine at Harbor Freight Tools but the internet shows they no longer carry them?

agoutihead
09/02/2007, 02:49 PM
alright what do you think about putting just a single fan in the middle as opposed to two fans on either side of the tank?

It's only a 40 breeder which is 36" long.

I am only have one - 175W single ended MH with a lumenarc reflector.

So since I am only having one bulb as opposed to a normal 2 bulb set up on most sytems, maybe 2 fans is a bit overkill?

I would then cut two - 2" holes in the top cornes to take advantage of convection.

AZDesertRat
09/02/2007, 03:02 PM
I think you will end up with dead spots on the ends. How about a fan in one end with a hole in the opposite side or a fan in back but as close as possible to one end with the air exits on top at the extreme opposite end?

agoutihead
09/02/2007, 03:11 PM
all of the designs will work, but which one do you think will be most effective?

You really think there will be dead spots with a single fan in the middle? I assumed it would deflect off the front part of the hood and roll along the sides to the back, up to the top and out the holes.

The opposite corner one will work too, but will it be an equal air flow like putting it in the middle?

Or should I just go with 2 fans on each end and just lower the rpms down in order to knock my rate of evaporation down as well?

AZDesertRat
09/02/2007, 03:19 PM
I prefer two fans but if thats not what you want I would recommend a fan on one end and exit on the other so air has to travel the length of the tank.

agoutihead
09/02/2007, 03:22 PM
I guess since I will have the variable voltage power supply, two fans is doable with out overkilling it, yet making it extremely effective.

Is it easy to reduce the power on these things? What is it just a little dial or something to turn?

AZDesertRat
09/02/2007, 06:14 PM
Yes, thye have a little knob or screwdriver slot that adjusts in 1.5V increments from 0 to 12 volts. I use 12v in the summer and either 9 or 10.5v in the winter when I do not need as much cooling since the house is cooler.

nanoreefbro
09/27/2007, 08:42 AM
<a href=showthread.php?s=&postid=10687490#post10687490 target=_blank>Originally posted</a> by agoutihead
I guess since I will have the variable voltage power supply, two fans is doable with out overkilling it, yet making it extremely effective.

Is it easy to reduce the power on these things? What is it just a little dial or something to turn?



So what did you decide?

agoutihead
09/27/2007, 10:26 PM
I haven't had any funds lately, so I haven't done anything. I'm planning on putting the two fans with the two exit holes that are equal size.

For now I just keep the front of my hood open so that the heat doesn't stay inside.

With the 175W, it doesn't really get super hot, which I am quite happy about.

When I do get around to it, I'll post some pics.

bigdaddyTank
09/28/2007, 11:07 AM
Some of the best fans are made by Yate Loon. Very highly used in pc cases, they move a good amount of air are are dead silent. Best of all they dont cost much, but are still a high quality fan. I have 6 of them in one of my PC's.

140 mm Yate Loon (http://www.jab-tech.com/Yate-Loon-140mm-Case-Fan-D14SM-12-pr-3594.html)

120 mm Yate Loon (http://www.jab-tech.com/120mm-Fans-c-81.html)

agoutihead
09/28/2007, 11:11 AM
Wow they are much cheaper than the Vantec stealths.

But what is the difference in the 120mm fan for 5.95 and the one for 3.95?

How do they compare to the vantec stealths in noise?

Has anyone else used them?

If the 3.95 ones are silent, I can probably buy them today as they are a great deal!

agoutihead
09/28/2007, 11:15 AM
ahh I see the db on the 5.95 is 24 where as the 3.95 is 40. Big difference.

http://www.jab-tech.com/YATE-LOON-120mm-Case-Fan-D12SL-12-pr-3009.html

but then there is that one for 3.50 and only has 28 db, is that really a big jump in sound going from 24 to 28?

Also there are two types, open and closed corners, what exactly does that mean?

flyguy7150
09/28/2007, 12:39 PM
agoutihead, go with the yate loons, they are great at a great price. I have the 3.50 ones, the D12SL-12. I have 2 of them on my 90, i havent seen the temp go past 81, hasnt even hit 81 yet. You cannot even hear them running. Running 4 54w t5s and 2 96 pcs. check out my build thread...shows how i wired them up as well
http://archive.reefcentral.com/forums/showthread.php?s=&threadid=1198787&perpage=25&pagenumber=1

bigdaddyTank
09/28/2007, 01:41 PM
The closed corners are solid between the screw holes on front and back. The open just have a hole in the top and bottom and a gap in between. Some cases and big heatsinks need a open corner for mounting.
If you go
HERE (http://www.pcper.com/article.php?aid=431&type=expert&pid=3) and look half way down the page they show what I'm talking about.
Jab Tech is a good place also, I'm spent a ton of money with them.

EDIT: HERE (http://www.xtremesystems.org/forums/showthread.php?t=137832) is a detailed review of some very good fans including the Yate Loons
If you want to spend the money the best fan out there is the Sanyo Denki San Ace (http://www.petrastechshop.com/12x38sadesan.html) big and quiet and moves a ton of air, its what I run on my CPU cooler. They are louder than the Yate's but if you 7v them they are very quiet.

nanoreefbro
09/28/2007, 06:53 PM
I heard Nexus are really quiet fans as well.. They cost a little more though.

bigdaddyTank
09/28/2007, 06:58 PM
Nexus are really quiet, they are re branded Yate Loon's

agoutihead
09/28/2007, 10:27 PM
yeah I'm gonna get the yate loons, the ones' for 3.50. I figure it will be 10 bucks total with shipping for 2. Thats a good deal.

then 5 bucks for the other thing I need to reduce the speed and wire them together.

Good lookin' out buddy! You saved me like 20 bucks!

flyguy7150
09/28/2007, 11:32 PM
reduce the speed?? they're not loud at all running full speed. If you have any 12v 300mA transformers around, itll run one fan.

nanoreefbro
09/30/2007, 01:49 AM
<a href=showthread.php?s=&postid=10687482#post10687482 target=_blank>Originally posted</a> by AZDesertRat
I prefer two fans but if thats not what you want I would recommend a fan on one end and exit on the other so air has to travel the length of the tank.

SocalCreations built a canopy for me and put 2 holes on each side. So should I just put one 120mm fan on each side?

pledosophy
09/30/2007, 02:14 AM
This is what I got, couldn't be happier.

http://www.frozencpu.com/products/4275/fan-236/SilenX_120x120x25mm_-_14dBA_-_72CFM_iXtrema_Pro_Fan_with_Fluid_Dynamic_Bearings_IXP-74-14.html?tl=c15s550b87&id=sZB6twVq

Extremely quiet, great at removing heat.

uscharalph
09/30/2007, 02:16 AM
You want cheap? I bought a couple of $5 fans @ Target and have them wedged behind my canopy. Works great. Keeps the temperature down in my tank.