Computer Fan Wiring

they make great fans... for small space growing

SWEET idea!
I learn so much here....
little chemistry, little politics, electronics, maybe robotics? hehe!
Cheers!

If you are looking for cheap 12v adaptors, look in your local thrift store / goodwill / salvation army. I just purchased three adaptors for my stealth box for 50 cents a piece...... all my fans are now working like a charm for under 2 bucks.

im no electrician. i understand wiring one fan to one adapter, but how would i wire say 2/3 fans to the same adapter? do i just connect them both to the same severed section?

i know it sounds dumb but im not proud. anyone got a pic? cheers la's xx

I wired 2 pc fans to 1 adapter. I wired them in a parallel circut and they have be working just fine for months now.

connect all the grounds together and then all the positives together positive + red ground - black so basically turn the one red positive wire into 2 wires one to each fan you can run it the other way but then you start to run more current threw your fans making more heat and putting un needed strain on them

you CAN connect multiple fans although they will only be running half speed. If you are using two 12v fans with only one twelve volt adaptor, they will split the diffrerrence, each fan will only be getting 6 volts of energy. It will work, but for the purpose of venting you want all the power possible out of your fans especially in a small area.

hi there guy's. i just tried rigging my fans up this way & it works a treat.
thanks for the information it been very usefull.
ive just rigged a third fan to one phone charger & because its running on reduced volts its silent now.

g0nz0 said:

you CAN connect multiple fans although they will only be running half speed. If you are using two 12v fans with only one twelve volt adaptor, they will split the diffrerrence, each fan will only be getting 6 volts of energy. It will work, but for the purpose of venting you want all the power possible out of your fans especially in a small area.

Click to expand...

If you connect two 12V fans in series across a 12v supply, you're right- they each will see 6V and will run at half speed.



However, if you connect them in parallel, they both see 12V and spin at full speed.



The yellow wire is for tachometry; a computer uses this to sense the rotation speed or to sense if the fan has failed. You can safely snip it when using computer fans for ventilation.

I have been using an old ATX 230watt power supply for my two 80cm computer fans. Talk about overkill on electric bill LOL. I have to try this on the cell phone charger! Thanx for this information. I was wondering if I could do this and thanks to your post I know I can. I think that wasted wattage can be put to better use (wink). I was going to buy more CFLs anyhow. I may just run the fans off one of those portable car jumpers. Then I could just recharge it by electric when it gets too low.

So its One fan per phone charger or can you attach multible fans??

AuntieSweetLeaf said:

I have been using an old ATX 230watt power supply for my two 80cm computer fans. Talk about overkill on electric bill LOL. I have to try this on the cell phone charger! Thanx for this information. I was wondering if I could do this and thanks to your post I know I can. I think that wasted wattage can be put to better use (wink). I was going to buy more CFLs anyhow. I may just run the fans off one of those portable car jumpers. Then I could just recharge it by electric when it gets too low.

Click to expand...

Actually...ATX power supplies dont use the alloted wattage unless it needs to, so youre pretty much only paying for the power you are using

Also, I think using the cell phone power adapter thing to run the fan isnt the best idea, because
1)if the amperage or voltage is too high it may cause the fan to burn out or something may spark and cause a fire, im no electrician but it just makes sense that connecting a device to something its not meant for would cause problems...buuuut if the voltage coming out of the cell phone adapter is less than 12v then by all means use it
2)You are not getting all the airflow (CFM) you COULD be getting if you put it to use at its full potential on 12v (what its designed to run on)

To connect it to an old computer ATX Power supply, you can just go to a local computer store (not best buy or circuit city, the ones that actually specialize in computer parts) and you can usually find tons of these for dirt cheap, as well as the computer fans. You can also go around the house to dig a power supply out of an old computer that you no longer use to find one.

To keep the power supply running (it does not run outside of a computer unless you do this), all you have to do is connect the green wire to any ground (black wire) wires from the ATX plug

a schematics to the power supply can be found here ATX Power Supply Wiring

This would be more viable for anyone running more than one fan, or wants more airflow for their setup

Thanks for the how-to. I'll be putting together my first grow box soon and was planning on using PC fans, so this definitely helps...

The link above is "dead" ... not sure if the sites just down or what ...

I've got mine hooked up via AC adapters of all sorts simply to move some air in a micro grow ... 1 6v, 1 5.9v and 1 5.5v rated adapters ... While this does work and isn't causing any problems "venting wise" .. i'd still like to see how to hardwire one of these atx PS' ... I have atleast 2 sitting around here .. I can't remember where but i saw somewhere say about moving the "switch" wire to a 5v connection off the PS ?... that it?

"short the green wire to a black wire on the psu to get it to turn on" <--- This is what i read ...

Taking the green wire "There was only one" off the 24 pin connecter and wiring it to a black wire via any of the 4 wire terminals worked ... and i must say, better than the ac adapters and only ONE cord to plug in ..

Do i need to have electric tape? and my cell phone adapter says 4.7-11v output what does that mean? Input is 250v Also it does not have two wires just one. ALso about the electric tape, is it used for jsut distance or does it have to be used to link the two wires?

Hello I Just Wanted To Know About The Yellow Wire Does It Matter To The Fan To Work I Know The Red And Balck Does Can You Get Back To Me Here Is My Email [email protected] Thank You For Any Of Your Help Mike

I've been an electrical nut all my life, self taught...

well not true, my dad built nuke missiles and taught me alot. But I learned everything about ac myself. I do my wiring on 120 to 240 volt live. saves me trips to the fuse box thats always locked in a room I cant get into ( commercial) so i skip that part and do it live.

slowly, 1 wire at a time.

I even rewired a shopping center in ohio, I replaced all the aluminum wire from the 70's including the pole lights at 480 volt 3 phase...no I did not do those live. the panels that feed those are 1000 amps. I'm crazy, not stupid.


anyways, it's the mili amps I have no experience with.

what I'm wondering is. those 4 inch ac fans at radio shack. do they need current reducers or a pot. i noticed they draw very low voltage.

I'm really not rich and dont feel like wasting 30 bucks to watch a new fan sizzle and burn up. I have already dont that as a kid. ( grin )

with such a low current draw, will plugging into the wall fry it, or will it only draw that amount and work fine ?

I'm building a box but i have a 600 watt hps and a hid conversion bulb, i need more than a 3 inch dc fan.

i have an inline vent fan i bought with the light but it's too big/loud. i want to use the smaller quiet 4 inch ac fans.

any help would be cool.

Al B. Fuct said:

If you connect two 12V fans in series across a 12v supply, you're right- they each will see 6V and will run at half speed.



However, if you connect them in parallel, they both see 12V and spin at full speed.



The yellow wire is for tachometry; a computer uses this to sense the rotation speed or to sense if the fan has failed. You can safely snip it when using computer fans for ventilation.

Click to expand...

I respect the fact you made diagrams to help everyone... I just want to say... Those are the funniest looking fans! haha. Very retro!

greenweed420 said:

I've been an electrical nut all my life, self taught...

well not true, my dad built nuke missiles and taught me alot. But I learned everything about ac myself. I do my wiring on 120 to 240 volt live. saves me trips to the fuse box thats always locked in a room I cant get into ( commercial) so i skip that part and do it live.

slowly, 1 wire at a time.

I even rewired a shopping center in ohio, I replaced all the aluminum wire from the 70's including the pole lights at 480 volt 3 phase...no I did not do those live. the panels that feed those are 1000 amps. I'm crazy, not stupid.


anyways, it's the mili amps I have no experience with.

what I'm wondering is. those 4 inch ac fans at radio shack. do they need current reducers or a pot. i noticed they draw very low voltage.

I'm really not rich and dont feel like wasting 30 bucks to watch a new fan sizzle and burn up. I have already dont that as a kid. ( grin )

with such a low current draw, will plugging into the wall fry it, or will it only draw that amount and work fine ?

I'm building a box but i have a 600 watt hps and a hid conversion bulb, i need more than a 3 inch dc fan.

i have an inline vent fan i bought with the light but it's too big/loud. i want to use the smaller quiet 4 inch ac fans.

any help would be cool.

Click to expand...

A pot inline will reduce current not voltage.

*read* what the fan wants. 12VDC and .2amps? (or if in watts, dived the watts by voltage)

*read* the item supplying the fan. make sure it has the same voltage and at least the same amps.


(this whole PC fan idea is a bit strange to me)