How to run 3 PC fans without a pc power supply? for new grow box.

**mr.notsogreenthumb** · 11-17-2010, 05:54 AM

So I am building a new PC grow box and I want to add 3 pc fans to the mix. Now I’m not the worlds greatest electrician but even I know that powering those three pc fans cant be done directly from the wall sockot.
The question is, “What sort of adapters and things will I need to make them work?” and no I am not willing to run an actual pc power supply just for three little 12v fans.

**NewClosetGrower** · 11-17-2010, 05:57 AM

find an old cell phone charger, or something along those lines thats closest to the voltage rated for your fans without going over and wire em up

**Jefferstone** · 11-17-2010, 05:58 AM

Close...you already know the voltage is 12. You need to take a look at the fan(s) and find either the watts or amps. You need to find a 12v adapter that matches those total amps as closely as possible. For instance, I have three PC fans that draw .160 amps each. If I wire them together I get .480 amps total, so I hook them up to a .5 amp 12v adapter and I'm good to go.

**Saerimmner** · 11-17-2010, 06:00 AM

yup what he said, there are a couple of articles on this very subject in most areas of this forum

**mr.notsogreenthumb** · 11-17-2010, 06:08 AM

I have got stacks of old phone chargers so that fits the bill well. But can I just cut the end off and put the fans directly on them? and do I have to get a charger for each fan or can I link them all to the same one? and if I link them all to the same one does the charger need to put out 12v or 36v in order to acomidate all three?

**brownbearclan** · 11-17-2010, 06:13 AM

Yep use a cell phone charger or 12v cordless tool charger, anything that has nothing higher than 12v. Desperate help with computer fan

If you're running 3 fans though a spare PC power supply would be ideal, you can get one for super cheap off newegg.com, craigslist, etc. etc. Then you just run a paper clip from the green wire to a black on the Motherboard plug to keep it turned on and just use a timer or whatev; http://www.youtube.com/watch?v=u0OKmIuNtmI

**Jefferstone** · 11-17-2010, 06:20 AM

Volts is Volts....if you have something that is 12Volt then no matter how many of them you have wired together they are still 12Volt. Like I said in the earlier post, get a 12V adapter that closely matches your total amps and connect the fans together.

**mr.notsogreenthumb** · 11-17-2010, 06:24 AM

Thanks. I have some old P2 and P3 power supplies lying about that I can use but I will try the charger thing first. Nice video link by the way.

**Jefferstone** · 11-17-2010, 12:27 PM

Not that you shouldn't use a PC power supply, but they are usually a couple of hundred watts. You really only need 10 or so. If you are watching your electric bill, every little bit counts.

**iforgotagain** · 11-17-2010, 02:52 PM

Go to your local electronics store and purchase an AC to DC adapter with variable DC output.

Find the amperage of each fan, lets say the fans draw 300mA or .3 Amps. Since you are running three fans off the single transformer, each pulling 300mA, you would need 300mA * 3 or 900mA. In that case, I would purchase a variable AC DC transformer with at least 1000mA or 1 Amp output (Personally I would go for 3Amps to be safe, too many amps doesn't hurt).

This configuration would allow you to change the DC output from the transformer between usually about 1.5V to 12V, which is a poor mans speed controller