power for CPU fans to cool tank?

[justinm000]

currently my tank's been too hot so I've planned on using 5-10 CPU fans to cool my canopy and maybe my sump area. I was wondering the easiest way to power these. I currently plugged in 3 to a wallwart but I don't think it can handle much more of a load. I'm thinking a PC power supply but that might be overkill and they're usually pretty open and I plan on having it next to my tank. Is there a cheap item that'll provide 12v power with like 3-5amps and is energy efficient?

[kimber45]

http://www.svc.com/pa-ad-ul-12v5a.html

i would use less large fans then more smaller ones. a couple 120's would move a lot of air.

[snulma1]

The problem with a PC power supply is that it needs something to control them and turn them on. If you want to run a bunch of them I would buy a 12 V converter, wire the fans in series and plug them into the converter.

That would allow you to plug the converter into a timer/controller so that it would turn on with the lights

[lighthouze08]

http://www.crazypc.com/products/psad24-7420.html
the current is 2A at 12v, plenty enough for what you need

[EnderG60]

The problem with a PC power supply is that it needs something to control them and turn them on. If you want to run a bunch of them I would buy a 12 V converter, wire the fans in series and plug them into the converter.

That would allow you to plug the converter into a timer/controller so that it would turn on with the lights

Nope, you can jump two wires to make it run like any other power supply.

I pulled a 75w one out of an old computer and used that to power all 15 fans on my system. Its run off my AC3 also, works just fine.

Plus then you can just hit up www.svc.com and get some of those thermostatic fans for like $6-8 each.

[Ben's Reef]

Nope, you can jump two wires to make it run like any other power supply.

I pulled a 75w one out of an old computer and used that to power all 15 fans on my system. Its run off my AC3 also, works just fine.

Plus then you can just hit up www.svc.com and get some of those thermostatic fans for like $6-8 each.

I need to add some fans to my hood also. I got a few old computers sitting in the garage. Sounds like I'm going to finally put those old dust collectors to some use!

:dance:

[kimber45]

If you want to run a bunch of them I would buy a 12 V converter, wire the fans in series and plug them into the converter.


don't wire fans in a series unless you don't want them to run at full speed.

Nope, you can jump two wires to make it run like any other power supply.
.

dark green to black. ;)

[100%hydrophylic]

idk if im allowed to link to this, but this is probably the easiest thing you could do.

http://www.talkingreef.com/forums/diy-projects/3590-make-no-frills-tank-cooling-fan.html

you can put multiple fans on one wall wart. (i think you have to make sure you have enough amps though. but i dont think thats a problem. i have a 1.5amp wal wart and my fans only draw like .1)


sorry if that breaks any rules but it was very useful for me.

[Snookster]

I wire mine up to old cell phone chargers.

[BeanAnimal]

Just a warning... an ATX power supply should NEVER be run without a load on the 12V rails! Let me repeat for clarity: Computer power supplies MUST never be run without a load connected to the 12V leads.

[kimber45]

most fans are 12v bean.

[BeanAnimal]

most fans are 12v bean.

The warning has nothing to do with the fans... of course most case fans are 12V :)

The warning was posted so that anybody attempting to use a PC ATX power supply understands that they can not be run "no-load" under any circumstances. Most supplies will list a minimum load on the rating tag. Not heeding the specifications can cuase malfunction, including fire.

[kimber45]

i don't like the idea of using a computer psu in a aquarium environment.

to open of a design. it's bound to fail.

i've had psu's that wouldn't even run without a 12v load.

[BeanAnimal]

Yes, in general it is a bad idea... but people sometimes don't listen to well founded advice :)

Dedicated linear or switch mode supplies can be found at very reasonable prices. eBay usually has a pile of them, as does mouser, digikey, allied, etc.

[xrunner1234]

Just a warning... an ATX power supply should NEVER be run without a load on the 12V rails! Let me repeat for clarity: Computer power supplies MUST never be run without a load connected to the 12V leads.

Just curious What's the failure mechanism due to no load? What fails and what catches fire?

[BeanAnimal]

Long story short... switch mode PSUs have a vairable efficiency curve that varies based on load. In general terms, the higher the load compared to the maximum output, the more efficient the PSU. The circuits in ATX power supplies are designed to reach maximum efficiency at somewhere near 50% to 60% (if I remember) of their load. The trade-off of the steep efficiency curve is that they become VERY inefficent when driven at low or no-load states. This inefficent operation generates heat and in general drives the circuit out of it safe operating parameters. The ATX standard indicates that ATX PSUs should have no-load protection to shut them down in the event that they are driven into no load. In reality many (most?) ATX PSUs are hunks of crap that are built with the bargain basement components that are being somewhat overdriven even on a good day. Blown filter caps, transistors and rectifiers are very common. It does not take much to get an electrolytic cap to explode.

[reefermad619]

So is it best to just use a walwart then?

[Ben's Reef]

I've got a 12V ADP25 Homedics Transformer Power Supply doohicky lying around.

Input 120v
Output 12VDC 2500mA

I slapped on one fan and it didn't blow up. I figured it could handle the load of 4 with no difficulties since it has that 2500 mA. I'm not pretending to know what I'm doing however and wanna make sure I'm not going to fry my fans or burn down the house.

Can anyone advise me as to the capabilities of a 12VDC 2500 mA Transformer / Power supply?

http://i216.photobucket.com/albums/cc95/Steelshanks/pics/adp25007.jpg

[IronMan72]

I've got a 12V ADP25 Homedics Transformer Power Supply doohicky lying around.

Input 120v
Output 12VDC 2500mA

I slapped on one fan and it didn't blow up. I figured it could handle the load of 4 with no difficulties since it has that 2500 mA. I'm not pretending to know what I'm doing however and wanna make sure I'm not going to fry my fans or burn down the house.

Can anyone advise me as to the capabilities of a 12VDC 2500 mA Transformer / Power supply?

http://i216.photobucket.com/albums/cc95/Steelshanks/pics/adp25007.jpg

That PSU is rated to supply 2.5A. Wire the fans in parallel (all positive wires connected to each other and all negative wires connected to each other) and you can power several 12V fans safely. :thumbsup: