use a pot to control speed of the fan (via voltage limiting) and DONT PLUG THE FUCKER INTO A WALL PLUG wall plugs are AC comp fans are DC.. hit a thrift store for an appliance that runs off a dc powersource.. anything that has a big black box that plugs into the wall instead of just a normal cord.. and READ.. MAKE SURE IT SAYS DC thoes fans will take up to 14 ish volts.. if you find one that is higher you can use resisters.. (or a POTentiomiter) to reduce voltage to a usable voltage but double check it says DC not AC

No!! Resistors are current limiting devices. A pot *can* drop voltage as can 2 resistors.
for a pot to reduce voltage wire it up like this.

------------------POS
|
|
\
/
\
/
|
|<----------------> to pos on fan (this is the divided voltage)
|
\
/
\
/
|
|
------------ GRND


Just get a pot or resistors that are rated for the power the fan is going to use.

Now if you notice, in this simple voltage divider, the resistors are not in series with the power, but strung across the rails.

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The Temporary Relief Assistant Trailer Park Supervisor. Carmelisous Jornl :: ElecUsageCostsCalc

would a 15v adaptor from an old laptop work to runn two 12vs safely? or would it fry it? it's definatly a DC adaptor?

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MAN! made beer, GOD! made weed. Who do YOU trust?!

You can buy a 12v adapter at Wal Mart for like $10. Just hook it up to the computer fan and you can plug it into a wall outlet. Don't use the 15v, it is too much. Spend the $10 and do it right.
I use 2 130cfm computer fans in veg, and they are both connected to the same 12v adapter.

wow, i been doing some search on a way to move air @ my friends 10x10 room grow area.

i was looking for a balance of price/performance/noice

now the idea is to run an air duct from a romm into this room and yet the same thing from this room out to an other.

i been looking at all kinds of fans, blowers, wall fans, air inline duct fans, cpu fans, ...

since i am a home depot kind of guy, they sell a inline air duct fan for 50 bucks that moves 120 cfm and is pretty loud

online hydrodealers sell fans that are similar but cost a shit load more.

and theirs 120mm computer fans that move over 100cfm are smaller, quiter for as low as 10.00 each.

so seems like a computer fans for the win.

so am i missing something, or are these lil fans the best bang for the buck. im not talking about moving air out of a box, but a whole room.

for 40 bucks i could have two fans breathing air in and two out. thats has to be at least 100 cubic feet of air per minute going ou/in .

in a 10x10x10 room thats 1000 cubic feet. thats a matter of having the fans run for what? 3 times a day for 25 mintues at a time to play it safe. ???

If its a 10'x10' room, to light it properly, you will need like 4000watts. If you are running 4000watts, you are going to need a lot more than 100cfm. More like 1,000cfm. The fans not only bring in fresh air, but also keep the temps down. With 100cfm on 3 times a day for 25 min, you are going to have dead plants in no time. If you have no idea what you are doing, don't go so big. Start with a nice small 400watt or even 250watt grow, then work your way up. You'll be happy you did.

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I do not grow/condone growing marijuana.All pics posted are from the internet.
C-99 Grow Log- http://www.rollitup.org/grow-journal...-grow-log.html

yeah for sure, im no where near 4000watts of light juice. i am going small and working my way up, by small im talking about 6 plants and cfls for lighting and keeping them at a 24 inch height through out growth.

but my main point was to how strong those lil fans are, and for the price.

12 VDC vs 12 VAC is a totally different animal. Please read labels before killing items.

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The Temporary Relief Assistant Trailer Park Supervisor. Carmelisous Jornl :: ElecUsageCostsCalc

My fans say DC12V, and my adapter says universal AC 12V adapter. They have worked fine for over a year on 24/7.

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I do not grow/condone growing marijuana.All pics posted are from the internet.
C-99 Grow Log- http://www.rollitup.org/grow-journal...-grow-log.html

I didn't read the whole thread, so this may have been mentioned, but since a pc psu is ideal, but most these days are ATX, and have no switch.. You can turn on an ATX psu by shorting the green wire on the mobo connector to ground (black).. Install a switch.. Then yellow wires are 12V, red are 5V, and the rest are low current voltages.. dc fans can be run at any voltage to desired speed/sound fine, ac fans are more dangerous to tinker with..
I heard a phone charger mentioned, thats probably really low output.. I use wall adapters too, they have their rated outputs printed on them.. Overloading them will burn them out eventually, but I've never seen anything dangerous with my own eyes..