Fans for cooling lights

SWANN

New member
Can anyone suggest any Good fans for my hood. The'll be placed in my full hood, which has 3 X 400 Watt MH and some VHO in it. I'm looking for quit and long lasting.

thnks Chris.
 
I have had great luck with 120mm Vantec Stealth fans myself. They are pretty inexpensive at places like Frys Electronics or Newegg.com and can be powered by variable voltage power suplies to vary the speed. Mine are so quiet most people who come to visit my tank remark on how quiet they are.
 
What I am getting at, is that I cant just wire these fans to some normal wall plug/extension chord..and plug them into the wall right?
 
You wire them to a DC power supply like a cell phone charger or other DC tool/appliance has. Those don't draw much power so a single supply should power 3 or 4 of them. You can get power supplies at WalMart, Frys Electronics or Radio Shack for $8 to $20. Get a variable voltage one so you can speed up and slow down the fan speed by varying the voltage.
All you do is cut the DC side plug off the supply and splice the 2 wires back 1/2" or so. On the fans strip the red and black wires back 1/2", ignore the yellow wire you don't need it. Twist the reds together and to one of the power supply wires then do the same with the blacks and the other supply wire. Before you make permanent connections plug it in to make sure the fan rotation is what you want, if they are blowing backwards swap the red and black wires.
Once you have the fans mounted use butt splice or crimp connectors and either black electrical tape or shrink tube for the permamnet connections. Plug them into an appliance timer along with your lights and you are ready to go. Set the power supply to 12 volts for maximum speed and dial it down to 10.5, 9, 7.5 etc to slow them down and make them even quieter.
 
Here's what I'm using.

http://www.ibsstore.com/Scripts/prodView.asp?idproduct=6420

They're AC fans so they don't need a separate power supply (but you can't adjust speed either). They're very solidly built with a metal frame and hold up better than DC fans I've used when mounted horizontally (my DC's developed a rattlling sound). At 30dB they will probably be audible in most rooms, but it's an unobtrusive sound and at 76cfm you won't find anything quieter. Very good fans if you need to move a lot of air. Oh, they also require standard fan cords that simply plug into a set of prongs on the fan.
 
not going to promise that this is the most quiet fan in the world. But it will MOVE air. 110 CFM is A LOT!!!
it's not so much the sound the fan itself makes...it's the sound the air rushing through the panel makes.

To power PC fans you could use power adapters like mentioned above from radioshack or where ever you can find them locally.
or you could use an old computer power supply.

I bet if you get something in the 70 CFM range, you're going to wish you had more than one. And at that rate, you might as well get 1 or 2 of a higher hardly much more louder CFM fan.

You don't need intake fans as much as you need exhaust. With fans it's always easier to suck air out, than it is to push in.

I would recommend exhaust only or intake+exhaust. Don't position your fans to blow into the fixture unless you absolutely have to. of course having both causes the air to move much more easily.
But you should always have exhaust fans.

The down side to using them as exhaust is, heat.
the heat from the fixture can shorten the fan life.
So obviously the more you spread out the heat the better.
= more fans, higher CFM.
It will pay to put some real thought into how you're going to lay your setup out.

Put those Engineering skills to the test brother!!!
 
Exhausting damp air kills fans, obviously you have not been doing this long. You do not need high CFM fans. Think about it, your canopy is probably 12 to 18 inches high and maybe holds 10 to 20 cubic feet of air maximum? Its easy to figure LxHxW. How many air changes a minute do you think it takes to keep a canopy cool? 2 or 3 is plenty. High CFM almost always means higher speed and more noise. When looking at dBa sound ratings keep in mind the difference between 25 dBa and 30 dBa is tremendous.
The fan couldn't care less if its pushing or pulling, it does the same thing as long as you have sufficient exit holes so you do not build up pressure in the canopy which in turn slows the fan and lowers the CFM.
For best fan life have the blow in, they stay cleaner and last longer since they do not build up salt spray coatings. I have probably tried 25 fans in the last 20 years and have yet to find an AC powered fan as quiet as a DC fan. The ability to vary the speed of a DC fan by itself is worth it in my estimation.
Computer power supplies are notorious power hogs and inefficient. You don't need 400 watts or more to power 4 fans that draw milliamps each.
 
Another thing to look at is that DC powered fans will be much safer than an AC fan.

DC will be about 12 volts and you will probably have a PSU that will put out 1000mA max. An AC fan will be getting 120Volts with a potential of 15 to 20 amps behind it -- depending on your breaker -- which around water can be a dangerous situation for you and your tank. And using a PC PSU is pretty dangerous as well as costly. Your average PC PSU will be about 75% efficient and it is putting out 12v 3.3 v and 5 v at very high amperages. So not only are you creating power ranges you are not using you are creating them at extreme levels. It is very possible to have a PC PSU discharge even if unplugged and put enough juice out to stop a persons heart.

So I would strongly suggest a couple DC fans powered with an old power brick. You could go to any number of places to get one and I truthfully suggest looking at an old answering machine or cordless phone you may have laying around or hit up a thrift store. You can probably pick one up for a couple dollars.
 
I got these for $23 shipped of ebay:

d1dc_1.jpg
 
Max,

I found this setup on ebay you posted but I couldn't find a sound/decibal rating. Have you installed these yet? How loud are they? I am looking for an already spliced setup like this but the fact that they didn't list how noisy they are concerns me.
 
This isn't a potential fire hazzard in any way? Just want to be sure before hooking up 3-4 fans to a variable voltage power supply.
 
nope - it's hard to start a fire with "most" plug in AC to DC converters. MOst will shut off if you try to draw too much current (a short, etc).
 
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