What's the best cheapest way to power my 12v dc fan?

Hi, I wanted to know what is the best, cheapest way to power my 12v dc fan? The only 12v dc adapter I found from simply walking to my nearest plaza was at radioshack, an AC/DC that costed 25 SPANKADOODLES! It's kind of difficult to find a place that doesn't have em for over 10 bucks too. And I could not find a 12v universal USB charger that plugs straight into the wall only those 5v ones. I wanted to know; if I modded a USB cable and connected it to a 5v DC universal USB charger instead of a 12v DC power supply would it be able to power my fan at high power; IF IT HAS A HIGHER AMP RATING THAN MY FAN? Or would it power it only half way, or would it not be able to work at all? I do not know the amp rating on my fan but the specs are 120mm by 120mm and 25mm thick and comes with LED pre-attached (will be deactivating that) so it probably uses at least 1 amp. I saw at best buy (online) they had a 12v dc adapter around 13 bucks but I'm not sure if they would have it at the store, and I would be disappointed to know I could have done something easier like using a USB adapter or bought something else and saved a little extra! I know I sound like a cheapass here but hey whatevs! Help?!

Here's a pic of the fan I got on ebay:
View attachment 2966064

http://www.ebay.com/itm/161193932902?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

Your fan is probably 0.15 amps. Don't you have an old cell phone charger or a router or something that runs 12v?

a 12v 1A adapter will run up to 5-6 fans. http://www.amazon.com/Wall-Adapter-Power-Supply-12VDC/dp/B006GEPUYA/ref=sr_1_2?ie=UTF8&qid=1390036238&sr=8-2&keywords=12v+1a+adapter

Tons of cheap ones from china, but it's gonna take a while to get to you.

avrum said:

Your fan is probably 0.15 amps. Don't you have an old cell phone charger or a router or something that runs 12v?

a 12v 1A adapter will run up to 5-6 fans. http://www.ebay.com/itm/Power-Adapter-AC-DC-12V-1A-US-plug-/121256598075?pt=Travel_Adapters_Converters&hash=item1c3b74da3b#shpCntId

Tons of cheap ones from china, but it's gonna take a while to get to you.

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Nah unfortunately I do not have an old charger lying around especially a 12v one b/c I recently moved here and all my stuff is in boxes in another state. Thanks for estimating the amp rating otherwise I probably would have fried it. I would be buying all my stuff from ebay listings in China but I do not want to wait. Do you think that a 5v battery with .5 amps would be able to push out double its current to get to 12v or more to power my fan or does it not work that way?

It will only push 5v.. But give it a try, it might be enough for your needs.

EDIT: I've changed the link in my first post to Amazon, shipment should be fast enough.

Do you have an old PC PSU lying around? could if you wanted wire it in using one of those for the time being while waiting for a 12v adapter?

Go to goodwill or the salvation army and look for used chargers?

The 5v USB should power up the fan, but increased Amps won't run it at full speed, it will run @ 5v @ 150mA's probably. If you have many fans running in parallel, increased amperage is good.

The 5v will work, I have [2x] 120mm fans and [1x] 90mm all being run off a 5v 1A chargers, it can work..

Another thing a "regulated" 12v power brick usually provides too much voltage with so little of a load on them. If it pushes 500mA, you want your devices to run together around 500mA.

When you run 150 milliamps on a 12v 1A charger [or even less], a lot of times they can be getting 16v's or more, not good on your fans, you have to regulate them. I use inline linear pots to set below max voltage, so I don't have voltage spikes. Phone/misc/device chargers are notorious for this.....


This is the reason why PC power supply's are so rock solid, they have VERY regulated small current and voltage. Size and amount of power is another discussion.

Abiqua said:

Go to goodwill or the salvation army and look for used chargers?

The 5v USB should power up the fan, but increased Amps won't run it at full speed, it will run @ 5v @ 150mA's probably. If you have many fans running in parallel, increased amperage is good.

The 5v will work, I have [2x] 120mm fans and [1x] 90mm all being run off a 5v 1A chargers, it can work..

Another thing a "regulated" 12v power brick usually provides too much voltage with so little of a load on them. If it pushes 500mA, you want your devices to run together around 500mA.

When you run 150 milliamps on a 12v 1A charger [or even less], a lot of times they can be getting 16v's or more, not good on your fans, you have to regulate them. I use inline linear pots to set below max voltage, so I don't have voltage spikes. Phone/misc/device chargers are notorious for this.....


This is the reason why PC power supply's are so rock solid, they have VERY regulated small current and voltage. Size and amount of power is another discussion.

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Hey I tried with a 5v 1A, but it does not at all seem like full speed: I need more voltage- to suck in more air, because the box is all the way in the corner, so the air that the fan pulls in may not be fresh enough if the fan is too slow to catch it, but then again I can rearrange things so my box is closer to my windows because stealth is not really an issue for me anymore.

You can always try someplace like this : http://www.coolerguys.com They sell all sorts of small case cooling systems including separate power supplies with molex (Those white power connecters used with most pc style fans) Believe one was about $11. Saw some manual speed controllers as well up there. Shipping is extra though If you want to bust out the wallet they have a complete setup for around $50 that is temperature controlled http://www.coolerguys.com/cabcool1201.html .

I've dinked around with 12V PC fans plenty. For PC's, not re-tasked for growing, but it's all the same. The above advice is good, but it sounds like you could use a little more help.

Do you have anything like Goodwill or Salvation Army where you live? Any place that sells things which have been cast aside by our modern throw-away society? You're looking for a wall wart-type power supply that provides 10 to 13V. It won't hurt to over-volt a PC fan by a little bit. It might burn up faster but if you put your mind to it you should be able to get more fans.

As you found out, 5V will just barely spin a PC fan. You'll need at least 7V, and that probably won't be enough. There is no harm in using a 7V wall wart or 8V or 9V, the fan just won't spin as fast.

Instead of having a discussion about amperage, which most people don't understand anyway, I'll just say this - look for a physically large wall wart. Let's say you found a thrift store near by with a box full of wall warts. You pick up a little tiny one, no bigger than a pack of cards. It says 12V. You might think you found what you were looking for, but if it's tiny it was probably built to recharge an electric razor, or some other very modest task. You reach back into the box and pull out another one. This one is 3X bigger than the first one. It also says 12V. The big one was probably built to power a printer or an LCD monitor or some other device that consumes more power. That's the one you want.

Millions of old printers have been retired, and many of their power supplies are still laying about. An old 12V printer power supply would be just about perfect for your needs.

Don't worry about getting one that's too powerful. The fan will draw what it needs.

Again 12v supplies are fine, but when you run small loads on them, they will spike, 99% of them.

A 5v fan will spin fans just fine. I have an almost 4 cu ft cabinet with about 100w's of LED's. Again, I run 2x 120mm fans and a 90mm fan all of of this one 5v 1A ex phone charger. It exchanges air.

It's not about barely spinning, it's about sizing for correct airflow. Once you have that, size and power is irrelevant.