Im trying to get my grow box together and im using a PC box but i dont know how to hook up computer fans and im not sure if two computer fans is the way to go (one for air to go in and the other out) im lookin here...http://shop4.outpost.com/search?cat=-51736&pType=pDisplay But idk if it will work or not if those are a bad idea then what kind of fan would be the best?
If you're using regular old PC fans then they're going to be 12v DC which means you'll need a 12v DC power supply. You might be able to find one from an old "wall wart" used to power cordless phone bases, or old networking equipment or something. Just make sure it says somewhere between 10 and 18 volts(PC fans really aren't that picky) and make sure it says DC, not AC. When hooking it up if there are more than two cables on the fan, the yellow one is the 12v, the black one is the ground, otherwise, black is ground, other (red, yellow, or white) is 12v. This is what a wallwart looks like. This one shows an input of 120v (normal wall power in many countries). Its output is 12.5v AC, which is wrong for your application. If it were 12v DC then it'd be perfect.
Yes. They'll just rotate a little slower. I run a variable voltage adapter so I can mess with fan speeds. It's currently running at 3V just to keep air exchange ticking over.
ok great thanks, i just hooked it up and it does spin a little slower then id like but for right now i think itll do the trick, i just need a exhaust fan now
do i need a fan that enters and exits? Cause i have both they are in the PC box and if i do need them is it ok if the fan that enters is faster than the one that exits?
Not necessarily. Not really, and certainly not if odour management is (or will be) an issue for you. As you describe it, the faster fan would create pressure inside the box, pushing excess air out through any cracks and vents, and with it a healthy (hopefully) smell of marijuana. Ideally you'd want to switch the fans in your scenario, so that the faster fan acts as the exhaust, creating negative pressure inside the box, which will draw air into the box through any cracks and vents. This makes odour simpler to deal with as it only exits via your exhaust fan.
There's a thread on another forum that answers your question, with pictures. http://www.icmag.com/ic/showthread.php?t=70035