Questions from a newbie about fans

[Lily of the Valley]

Hi everyone, I'm still at the planning stage. I need some expert advice and know-how for my first attempt at growing weed:

 

For my grow tent (a space of 45cm x 90cm x 160cm) I plan on using 2 computer fans - one fan for ventilation to extract air out, and another fan which is apparently meant to cool things down....?

 

...let me get this straight: if I'm using a warm 250 watt CFL light (CFLs don't generate nearly as much heat compared to HPS), I still need to use a fan, right? And where exactly is this fan supposed to go? Right in front of the lamp? To the side? Or what about on the plants? Please clarify exactly WHAT needs to be cooled down - the plants or the lamp? People say different things and this confuses me. Some people use fans which blow on their lamp, but as I'm using a CFL which won't get that hot, I'm not sure whether it needs that much cooling. And other people say that they use cooling fans to blow on the plants.

 

As I mentioned earlier, I'm using two computer fans (the kind you get at Chinese computer parts stores). The reason I want to use these instead of hydroponics fans or can fans is that A they are relatively quiet (around 19 dB or less, which is silent enough) and B relatively inexpensive. Can fans might be quiet but they are beyond my budget, and all the hydroponics fans I've come across make too much noise (around 44 dB). Noise is a hugely important factor in my secret weed growing operations because I'm still living in my mother's house. Silence is of prime importance (I cannot stress this enough).

 

The biggest problem I face is that these computer fans are meant for COMPUTERS and so they come with all this complicated fiddly wiring attached to them (red and yellow cables), and no powerpoint plugs . Well, of course they're not meant for hydroponics, they're meant for computers..... because of that, I've been told that the only way to power them is through a computer power box. I'm not sure where to get that or how to connect that up to a powerpoint. Perhaps there is an adaptor you can connect to the powerbox?

 

If anybody here has used computer fans, could you please explain to me how you managed to wire-up your fans to the power point or somehow got them to work. Thanks.

Edited June 27, 2008 by Lily of the Valley

[larfin1]

If anybody here has used computer fans, could you please explain to me how you managed to wire-up your fans to the power point or somehow got them to work. Thanks.

 

Easy as mate, just grab a 12volt ( usually) transformer and hook it up.

 

From my experience if you hook it up the wrong way the fan will just run backwards until you reverse the wiring.

 

 

you could even use a pc power supply if you have one lying around.

[Lily of the Valley]

^ Thanks larfin1.... OK, I will look out for a 12 volt transformer you speak of. Does it look anything like this:

http://www.rockaroundtheblock.com.au/categ...66&c=274515

 

And where could I get this at a cheap price? Does the power supply or transformer come with a chord that attaches to a standard powerpoint? Do you plug in the computer fan's wires into the transformer/pc power supply?

 

Here are the further specifications of the computer fans I'm getting: ( I just jotted this down from the package in the store, so I don't know what most of these things mean)

 

Brand = "Cooler Master"

120mm in diameter

Speed = 2000 RPM (I have no idea what that is)

Airflow = 69.69 CFM (don't know anything about CFM, or how much airflow I need)

Air pressure = 2.94 mmH20

Noise = 19 dBa

Voltage = 12VDC

Connector = 3 to 4 pin adapter

 

*All of this information and the product is here:

http://www.coolermaster.com/products/produ...ail&id=4410

 

About adaptors -

I just came across this item on Ebay:

http://cgi.ebay.com.au/12-Volt-Transformer...oQQcmdZViewItem

 

^ Apparently it's a 12 volt transformer. I think this is made for a dollhouse, but do you reckon I'd be able to use it for the fans? And since I'll be using 2 fans, does that mean I need 2 transformers? Also, just how do you wire up all the cables that come out of the fans?

 

Sorry, I am full of questions, and no good with electric stuff.

Edited June 27, 2008 by Lily of the Valley

[larfin1]

Easy as mate, just grab a 12volt ( usually) transformer and hook it up.

 

From my experience if you hook it up the wrong way the fan will just run backwards until you reverse the wiring.

 

 

you could even use a pc power supply if you have one lying around.

 

 

um sorta but i wouldn't be paying that kind of money for one, i have a draw full of the things .

 

ideally speaking a pc power supply or an invertor will suffice. How you source as such is up to you but i wouldnt be paying that much for one.

 

heres an example http://cgi.ebay.com/240-volt-input-12-VAC-...VQQcmdZViewItem

Edited June 27, 2008 by larfin1

[Lily of the Valley]

^ ok, thanks. just how do you wire up the thing to the fan? and will I need 2 of these since I'm using 2 fans?

[Lily of the Valley]

Don't worry - I've got it all sorted out now. Thanks for your help. After doing more research online, I finally stumbled across this thread on another Cannabis forum somewhere, and they show you exactly how to wire up a computer fan here:

http://www.talkingreef.com/forums/diy-proj...ooling-fan.html

 

So now I'll go out and get myself this adapter.