How do you use Computer Fans to cool your Aquarium?

kookerson · #1 04/04/2007, 04:56 PM

I know Ive seen a couple people do it......but how? How can you hook it up so that you can power it in a standard house hold outlet? Also, Im kinda slow when it comes to DIY involving electrical stuff, can anyone help me out?

Duby · #2 04/04/2007, 05:07 PM

You just need a power converter or you could actually use a power supply from a computer which you can buy at almost any electronic place(Best Buy or Circuit City). The converter converts it from 120AC(house current) to probably 12DC(car current).

AZDesertRat · #3 04/04/2007, 06:44 PM

All you need is one of these and a computer fan.

http://www.harborfreight.com/cpi/cta...emnumber=46977

Cut the adapter plugs off and connect the two wires to the black and red wires on the fan and you are up and running. You might even have an old power supply around the house already from an old cell phone or other appliance.

rsw686 · #4 04/04/2007, 07:15 PM

You want 12V to run the computer fan. You can use a potentiometer to tune the fan speed to your liking. Less than 12v as thats what is happening if you use a resistance to lower the fan speed, but you might as well build it so you can utilize the full potential of the fan.

AC to 12V DC Adapter
http://www.radioshack.com/product/in...entPage=search

Adaptaplug with power leads to connect to fan. You could just cut off the adaptaplug on the adapter, but this way makes it easily removable to run the wire. Otherwise you have to maneuver the ac adapter with the fans attached.

http://www.radioshack.com/product/in...entPage=search

If you want to read up on varying the fan speed with a potentiometer

http://www.overclockers.com/tips746/

AZDesertRat · #5 04/04/2007, 07:20 PM

Way too much work and expense. The Harbor Freight power converter is variable voltage and only $4.99. I use two of them to power 4 Vantec Stealth fans and they are totally silent at 10.5V and cannot be heard unless I unplug my skimmer at 12v..

rsw686 · #6 04/04/2007, 07:26 PM

Right but that harbor freight adapter is only putting out 500ma. Most fans take around 200ma. I'd rather spend more money and only have one power brick down below with all the others.

Hows it too much work. Forget the potentiometer. Just having the adataplug allows you to easily mount the fans. Then just plug the adapter into the fans without having to carry the adapter around with the assembly.

calebjk · #7 04/04/2007, 10:19 PM

Kookerson, there are a few things you should take into consideration. First, the fans run on 12vDC so you will need a 12v power source. Second, how much power will you need. As noted above most cheep power adapters don't supply much power. First you need to decide what fans you want and then how many of them you will be using. If you pick a fan that runs at .50A and you want 3 of them, then you have to get a power supply that can constantly run 1.5A, but you should double that and make it 3A to be on the safe side. By the time you do that you are looking at some serious $ to pick something up at radioshack and you won't have much flexibility.
What i did myself and would recommend for you is using a power supply from a computer. You won't have to worry about overloading it and you can usually pick them up for real cheep at your local computer recycling center, around $15.
You also will not have to worry about splicing wires, although you may have to extend the wires on the fans, that should be simple.
In order to get the power supply to turn on you will have to do one simple thing, and that is jump 2 ports on the connector that usually plugs into the motherboard. this is very simple and you can do it with a chopped up paper clip. Here is a pic of how i did mine.

It just relays 5v back to the power supply to tell it to run.
There are some fans i can recommend to you also. Here the links.
http://www.newegg.com/Product/Produc...82E16835220009
http://www.newegg.com/Product/Produc...82E16835220014
Both of these fans are high quality, can move a lot of air, and come with great little knobs that will let you adjust their speed.

Best of luck

kookerson · #8 04/04/2007, 10:23 PM

Wow guys, lots of info, thank you very much! But honestly, it confuses the heck out of me.........I blindly thought to check out ebay, and for about 11.00 and zero headache I can get a dual fan unit. but thank you very much for your help!

silverwolf72 · #9 04/04/2007, 11:34 PM

How about just getting an AC fan

http://www.computerfanoutlet.com/fan...6&ProductID=53

AZDesertRat · #10 04/05/2007, 12:01 AM

AC fans are almost always more noisy for one and you cannot vary the sped for another.
I can run 4 Vante Stealths on one 500mA supply easily for $4.99. I choose to run two so its two 120mm or 4" fans at $11 ea and a power supply at $5 for a total or $27 for 106 CFM of variable speed cooling, pretty efficient cooling my book. 28 dBa at full speed which is pretty darn quiet.

eznet2u · #11 04/05/2007, 12:17 AM

Quote:

Originally posted by silverwolf72
How about just getting an AC fan
http://www.computerfanoutlet.com/fan...6&ProductID=53

46 dB!!! That would drive me nuts! Follow AZDesertRat's advice and stick with DC. They are VERY quiet and work great.

RobbyG · #12 04/05/2007, 12:33 AM

AC fan in the sump is just a bad idea, you never know when the fan might fall in the water or get sprayed with water and possibly short out.
Also computer power supplies / switching power supplies are by nature very sensitive to water and high humidity and will burn out quickly if exposed to either, not to mention the much greater chance of getting a nasty shock if moisture creeps from the circuit board to the metal housing (Like if wet hands handle it). Your better off following AZ's advice, use a DC fan and get a 12 volt 1000ma adapter. That will be more than enough and a much safer setup.

JOSEPHLB · #13 04/05/2007, 08:14 AM

As others mentioned, get the 12v D.C. computer fans. If they are rated to draw .5A, you still need to get the 12v D.C. power adapter rated to pump out more than .5A.

A few things to know.. The fan's current/amp rating is what it will draw. Just because a DC adapter is rated at 1, 2 or 3 amps doesn't mean that is what is going to be pumped into the fan. Voltage is potential; the potential to do work. The 12 volts is not going to do anything unless there is a force, driving the 12 volts. In this case, that is current. Resistance plays a factor in your current and voltage potential also.

If you wire two, 12 volt computer fans in series, there will be a voltage drop across the first point of resistance. In this case, the first computer fan. The second computer fan will recieve the remaining potential. If both compute fans are the same brand, make & model with the same specs, then the voltage potential will be the same for each fan.
If two of the same fans are wired in series, and they are fans rated for 12 volts, then each fan will only get 6 volts each, but the same current draw. In series, DC, current stays the same.

AZDesertRat · #14 04/05/2007, 09:13 AM

Always wire two or more fans in parallel or you cut the speed in half every time you add one to the circuit.

rsteagall · #15 04/05/2007, 10:22 AM

Yep, old computer power supplies work well for this sort of thing. If you can find a really old 150W or so AT powersupply, you don't have to worry with the ATX jumper thing.

silverwolf72 · #16 04/05/2007, 10:22 AM

Quote:

Originally posted by eznet2u
46 dB!!! That would drive me nuts! Follow AZDesertRat's advice and stick with DC. They are VERY quiet and work great.

Thats the same as the DC computer fan at full throttle. But DC fans are easier to tinker with than AC.

AZDesertRat · #17 04/05/2007, 11:01 AM

Vantec Stealth 120 mm fans are 28 dBa at full speed or 53 CFM each.
http://www.newegg.com/Product/Produc...82E16811999614

Two of those blowing in with proper sized exit holes give you over 100 CFM. If your average canopy is in the 8 to 12 cubic foot range that gives you about 10 complete air exchanges per minute which should cool just about anything. Always have fans blowing in for two reasons. 1. If one blows in and one out you really only have the CFM capacity of one fan, the second one is just moving along the air the first one fed it and not doubling the velocity. 2. Blowing in reduces salt creep and failure of the fans due to build up.

lsuberl · #18 04/05/2007, 11:31 AM

I think I might be in for the Radio Shack adapter and the plugs. How do I connect two fans to the power supply using those plugs? I think I want one fan at each end of the tank blowing in towards the light/water. Thanks guys! This will be a much better solution than the table fan I have sitting beside the tank, waiting on me to put together a better solution!!!

Vincerama2 · #19 04/05/2007, 01:52 PM

I don't see why AC fans should be any louder than DC fans!

I never compared the two, but that sounds weird to me.

The only fan I use is a $6 Walmart/Target/Canadian Tire/Sears/etc clip-on fan, which I only use when it gets really hot around here.

Of course it's a bit loud, but it's a big fan too.

V

in_flight · #20 04/05/2007, 02:39 PM

how many fans do you guys use in your tanks? i use 2 stealth fans in my 75g and it's nowhere near enough, i'm thinking of adding a few more in my sump

AZDesertRat · #21 04/05/2007, 03:53 PM

I use two stealths on timers in my canopy both blowing in with sufficient exit holes on the top for heat to escape and a 7" clip on over the sump on a Ranco controller as a back up.

How are your fans and exits configured? Are they running at 100% speed ie 12v.

elzool · #22 04/05/2007, 05:28 PM

I've used the Vantec Stealths for a while now, but was one fan short, so I bought another 120mm fan, this one was an Antec. It had a dba rating higher than the vantecs and the cfm it is said to push is less than the Vantecs, but in listening, it's quieter and when placing my hand in front of it it is obiously pushing more air.

Weird, but true.

Plus it has pretty blue leds... so I got that going for me.

calebjk · #23 04/05/2007, 06:22 PM

it's the fan with built in moonlights!!!

RichConley · #24 04/06/2007, 12:35 PM

Quote:

Originally posted by elzool
I've used the Vantec Stealths for a while now, but was one fan short, so I bought another 120mm fan, this one was an Antec. It had a dba rating higher than the vantecs and the cfm it is said to push is less than the Vantecs, but in listening, it's quieter and when placing my hand in front of it it is obiously pushing more air.

Weird, but true.

Plus it has pretty blue leds... so I got that going for me.

Look for Noctua, or Scythe. Vantecs are way louder and more expensive than either of these.

Using a computer power supply is a bad idea. Those big power supplies dont run for free. They're usually pretty inneficient, and use a bit of electricity monitioring themselves.

Vincerama2 · #25 04/06/2007, 01:18 PM

I actually heard (from some unreliable internet source!) that the computer PSU's are more efficient than AC/DC adapters. I have no real opinion, though someone with a a Kill-a-watt monitor could probably tell us.

V