Computer Fans in Canopy

[teresaq]

I need to add some fans to both my tanks. I have read about people useing computer fans, How and what do you use for a power supply.
I have som old ac/dc adaptors, will those work. How do you wire when the fan has 4 wires and the adaptor only 2.
The first picture is the fan I will be using, but I really like the second and third one, it has leds already in it and is like 8 inches.
This is the specs on the second lrger fan
Power Works 250mm Fan
250mm x 30mm Cooling Fan
Clear Fan Blades with BLUE LED lighting
Connects to 12 Volt Molex 4pin Connector
Quiet Operation only 20 dBA
Moves over 100 CFM
Requires 8-3/4 inch hole for mounting
Specifications
Fan Size 218mm/8-9/16inch diameter for clear fan housing
Overall Size 275mm/10.75inch diameter at the widest (includes bezel)
Fan Holes 250mm/9-7/16 measured diagonally from hole to hole
Fan Color Translucent blades with Blue LED
Fan Power DC 12V
Connector 4-pin molex to power supply
Wattage 11 watts
Amperage 0.9A
Fan Speed 820 RPM (+/- 5%)
Air Flow 105 CFM (+/- 5%)
Noise 20 dBA (+/- 5%)

 

[t316]

Never seen the fans in pics 2 & 3, but I did rig up a fan like pic 1. Bought the fan from Radio Shack. It's been a long time, but I do remember having to strip the wires and reconnect it to some plug I found at the dump. But, it did work very well as I recall.

 

[natclanwy]

Any 12v DC adaptor will work to power the fans, as far as the number of wires there should only be two actually used to power the fans and it should be pin #1 and #2 on the molex connector.

 

[aquaknight]

Originally Posted by T316
http:///forum/post/3028782
Never seen the fans in pics 2 & 3, but I did rig up a fan like pic 1. Bought the fan from Radio Shack. It's been a long time, but I do remember having to strip the wires and reconnect it to some plug I found at the dump. But, it did work very well as I recall.
Yep, two DC fans, an adjustable AC-to-DC converter, and an adaptaplug from Radioshack, and $65 later I was set...

 

[ifirefight]

If you look around...you will be able to find 120v AC fans (they have a "regular plug") no need for adapter. I have those on mine... Good news and bad news about the fans..good news is they work fine and kept my temp in check no problem. Bad news is, with those fans blowing...it is noisy...my wife said no more fans for me, I ended up buying a chiller. ( Im happier with the chiller ). My .02

 

[teresaq]

I found the fans for about 3 buck each, and I have a bunch of 12 v adaptors laying around. Since I need 7 fans, I need to go cheap
T

 

[natclanwy]

Computer fans are ten times quieter than 120v versions, $3 sounds like a pretty decent deal but usually the cfm drops off and the noise level increases on the cheaper fans. You could get by with less more expensive fans and still be quieter depending on the cfm rating of the cheap fans.

 

[spanko]

Just for information.
60 dBA Noisy lawn mower at 10 m distance
55 dBA Low volume of radio or TV at 1 m distance, noisy vacuum cleaner at
10 m distance
50 dBA Refrigerator at 1 m distance, bird twitter outside at 15 m distance
45 dBA Noise of normal living; talking, or radio in the background
40 dBA Distraction when learning or concentration is possible
35 dBA Very quiet room fan at low speed at 1 m distance
25 dBA Sound of breathing at 1 m distance
0 dBA Auditory threshold

 

[ifirefight]

Originally Posted by natclanwy
http:///forum/post/3029035
Computer fans are ten times quieter than 120v versions
This is the one I have..
Model No BT12038B1L
Bearing Dual BALL BEARING
Voltage 115 V
Freq 60Hz
Deminsions 120x120x25 mm
Rated Cur 0.10 A
Life Exp 50000 Hours
Speed RPM 2000 RPM±10%
Air Volume CFM 60 CFM
Sound Noise dB 33 dBA
Net Wt 330 Grams
The ones shes looking at do have better CFM and less dB...but my 2 fans (which I stated my wife thought were to noisy, = 33dB x 2 so 66dB ). Teresa says she will need 7 fans..so even at 20 dB each....it will be a little noisy.

 

[natclanwy]

I don't believe the db rating doubles with each additional fan, but 33db fan is much louder than a 20db fan. Also another reason to use less fans with higher cfm ratings then More fans with less CFM.

 

[aquaknight]

Originally Posted by natclanwy
http:///forum/post/3029092
I don't believe the db rating doubles with each additional fan, but 33db fan is much louder than a 20db fan.
Just gonna mention that. Same reason why you just don't see a thousand little speakers for audio competitions...

 

[scsinet]

Originally Posted by natclanwy
http:///forum/post/3029092
I don't believe the db rating doubles with each additional fan, but 33db fan is much louder than a 20db fan. Also another reason to use less fans with higher cfm ratings then More fans with less CFM.
No, it doesn't double, you're right.

When two pieces of equipment are running and are creating the same amount of noise each, the net noise level is somewhere around 20% higher than one item. So if two 30dba fans are running, you'll get about 31dba of noise radiation - it'll make sense... read on. This sort of thing is frequently discussed in woodworking circles as to what level of hearing protection you need when running two items at once... a sander and a dust collector, for instance.
You are also correct in your 33 vs 20. Noise levels (db) are logarithmic. Roughly, for each 3db of increase, the sound level doubles. A device generating 100db is not 3% louder than one generating 97, it's around 100% louder.
So in the stated example, a 33db fan produces somewhere around 4 times the sound level of a 20db.

 

[flower]

Originally Posted by TeresaQ
http:///forum/post/3028874
I found the fans for about 3 buck each, and I have a bunch of 12 v adaptors laying around. Since I need 7 fans, I need to go cheap
T
These will rust...Ice cap fans are the best, not cheap but they wont rust and they have 3 auto speeds as needed for the tank.

 

[natclanwy]

The icecap fans are very loud on the highest speed and for the price you could replace several computer fans before you would equal the cost of an icecap fan.

 

[flower]

Originally Posted by natclanwy
http:///forum/post/3029432
The icecap fans are very loud on the highest speed and for the price you could replace several computer fans before you would equal the cost of an icecap fan.
True about the icecap fans being loud on the highest setting...but computer fans are too tiny for the amount of air you want to move, and they are not made for damp areas. My ice cap fans work great and do the job I need done. They only run on high speed when the canopy gets hot and that's the idea.
A computer fan is about 2 inches square... way too small for a big tank. Not to mention you have to play with wires. No, I still recommend the ice cap fan.
There are other fans made for fish tanks that are not as expensive, but don't use a computer fan. JMO

 

[natclanwy]

Your right that you have to mess with wires but its 12v DC and you really cant screw it up if you wire it backwards either the fan won't run or will run the wrong direction depending on the fan. The is no chance of being shocked its really very simple and safe to wire them up.
Computer fans come in several sizes 80mm (3") and 120mm (4.5")being the most common and most 120mm fans will move as much air as the icecap fans at less than 1/10 of the noise level and at $12 you could buy four of them to one icecap fan.

 

[scsinet]

Icecap doesn't manufacture their own fans, they just take ordinary off the shelf computer type fans and slap their label on them.
Computer type fans aren't any more prone to rust or problems than icecap fans. Occasionally, fans have a small bit of shaft showing on the hub of the blade, but a dab of clear nail polish effectively rustproofs them.
I've used computer fans on several canopies over the years and have never had a lick of trouble.

 

[jackri]

I have 2 USED computer fans blowing under my halides, fastened down by sticky velcro so I can remove them for cleaning.... wired into a free 12v adapter source.
Saved 50 bucks from buying the coralife fans and got the same thing essentially.

 

[teresaq]

I ordered them. I got 3 that are 3.6 inched and 2 that are 4.75 inches. They should work just fine for what I want. I dont think I want to spend 250 dollars on ice caps when I spent about 20 for the ones I got.
T

 

[flower]

Originally Posted by SCSInet
http:///forum/post/3029674
Icecap doesn't manufacture their own fans, they just take ordinary off the shelf computer type fans and slap their label on them.
Computer type fans aren't any more prone to rust or problems than icecap fans. Occasionally, fans have a small bit of shaft showing on the hub of the blade, but a dab of clear nail polish effectively rustproofs them.
I've used computer fans on several canopies over the years and have never had a lick of trouble.
I can certainly understand the OP position. I have no argument...however your statement is not correct. My X husband built computers, and I was right there with him. Those tiny little computer fans are not at all what the ice cap fans are.
They most certainly did NOT slap their name on a computer fan. Those fans wouldn't even fit in a computer box; they are half the size of the computer!
All I am stressing is that the ice cap fans are much bigger and give much more air flow than the computer fans can.
They may look very similar in a picture, but in real life the size is way different. Canopy fans are made of aluminum, computer fans are made of metals that will rust and could transfer metals into the tank if condensation develops and drops into the tank.
There are cheaper canopy fans out there, Ice cap is not the only brand of canopy fan. You can even buy a regular clip on fan that would work great.
A computer fan is a little tiny 2 inch fan that has one low speed; it will make air flow, but not enough to move heat from MH lighting under a canopy. I have never seen a 4 or a 3 inch computer fan, I have only seen 2 inch square.