Cooling Fan basics ? Wiring ? Help I'm on fire!!!

[superdaveumo]

Most PC fans are run on 12V (some are 5V). To save some space, you can run down to your local Radio Shack and pick up a 12V AC - DC converter. It looks like the AC adapter you use for your portable CD player. Says 12V 500mA on the front. Very small. I would guess 3" x 3.5" x 2". Maybe $10.

You don't need 120W of power to run fans. I have 2 squirrel cage fans that run at 100 CFM and take less than 5W.

[escalade182]

although thats true. I would beleive he plans on running more then one fan... And a powersupply can literally be found, or given to... A 12v ac to dc wall charger will require soldering and cutting...stripping...and you can only run 1 fan off of it...

A computer power suppl is defently the way to go...
why?
-snap in connections
-up to 10 fans running without any speed lost.
-quick disconnection from unit (unlike a wall psu, which would take up space on the outlet)
-cheaper
-more reliable
-self cooling
-an many more...

check on ebay for a "90w PSU" or "90w Power Supply"...the dimensions are usualy around 2" x 5" x 6" (about a stack of 4 cd's) and will be:
1. very quiet (minature cooling fan to cool itself off)
2. very cheap
3. can easily power 10+ fans and other 12v accessories
4. TINY!

[escalade182]

MAKE SURE YOU DONT BUY A DC-DC POWER SUPPLY. this is only usable with a car battery. so you might want to add " -atx" to your ebay search

[dale cooper]

if you guys only had a tip jar ..............

will report results very very very soon
lots of final results with pics !!!!!!

[superdaveumo]

A computer power suppl is defently the way to go...
why?
-snap in connections
-up to 10 fans running without any speed lost.
-quick disconnection from unit (unlike a wall psu, which would take up space on the outlet)
-cheaper
-more reliable
-self cooling
-an many more...

And see, again I think this is a little overkill. A computer power supply will work but it is definitely hotter, bigger, and noisier than just a simple AC-DC power supply. I have 2 squirrel cage fans running on mine. I could easily put 2 more. If you ran 80mm fans, they use around 100mA, if that. 4 could be powered by this power supply. There is definitely no power problem. Even if there was... get the 1000mA version or the 1500mA version. WAY more power than you will EVER use on case fans. 90W is overkill. At around 1.5W a piece, a 500mA 12V DC power supply will run 4 of them. 1000mA will run 8 of them. That's only 6W for 4 fans or 12W for 8 fans. A 90W power supply is overkill unless you are running something else aside fans (like a PC or your LCD screen). Then a PC power supply would be worth it.

You don't need to solder either. If you can handle a pair of wire cutters and are able to screw on 2 wire caps, you're done.

An even better idea that GG has done is use an AC fan. Radio Shack carries them. No converters period. Uses the same power connection as your ballast and LCD power supply.

[escalade182]

again, if you want the full(safe) potential of each fan. psu. Its not over kill.

[superdaveumo]

This is just not true. It is cheap. It is quieter. It is safe. It is smaller. It is cooler (physically).

Case fans are generally 1.5W each. Most DIY projectors have 2 - 4 fans (ie 3W - 6W of total power).

You can use a 500mA AC-DC power converter from Radio Shack; which can handle 6W SAFELY. If you need more fans, you can get the 1000mA version. That's 12W total or 8 fans. $16 - $20 brand new (no shipping).

The 90W PC supply you speak of is 15 times too much power for just fans. Why use a butcher knife to cut up carrots? By having a fan, this power supply is obviously louder. At 90W versus 6W or 12W, it also creates a lot more heat. In a case where you want to keep things cool, I would think you'd want components that are cooler running. Being a PC power supply it is also bigger.

I'm not saying that a PC power supply is the wrong choice. I'm just saying that a AC-DC power converter is just as good at running fans. If you want to use a PC power supply, that's fine. It's probably cheaper and a little easier to plug and go. Make your own choice based on what you need.