Hi all, I have built an AV cabinet in the eve's of a loft conversion which is a very hot room. The cabinet is open on the front and the back but the air is stgnant and I want to put some fans at the back of the cabinet to either push or pull air through the cabinet. I have found this http://www.kustompcs.co.uk/acatalog/info_2962.html which would be ideal to conect the fans too but I have no idea what sort of power brick to buy to power it or how to conect the molex cable to a normal round 12V power conecter.
Cut the barrel jack off and solder the wires directly to the back of the female moled connection on the circuit board. Any 12v DC wall-wart that can provide upwards of 1.5A or 2A (to be on the safe side) will be fine.
You would need a power adapter that is 12v with enough amperage for the fans. It should say on the fans how many amps they draw, but most are below 0.9amps. ah, beaten by pedro
Thanks guys, Lets say for the sake of argument the fans need 1 amp each that would be 6 amps total. I've had a quick look on Maplin's web site and the most a regulated power supply will do is 1.2 amps or have I missed something? As for the wiring a standard Molex connector has two grounds a 5V and a 12V line where as the power supply only have a 12V and a ground connection is that all I need to hook up?
yea, that is probably a limitation of the wall style adapter itself. There are a few laptop style adapters that are around 6amps, but they probably aren't cheap. You could also consider using an old or cheap PC power supply as then not only would you have adequate power draw, the molex connectors would also be better suited for the fans.
+1. You should be able to find a "cheap" PSU for about $20 or so. Just jump green to black and you are set. I use a cheap ATX PSU to power DC motors, circuits,etc.
Fans are supposed to be <3W (3W/12V=0.25A). 6*0.25A=1.5A 1A per fan is real overkill. A CCTV power brick (like a big wall-wart) can do 2A or 3A easily for about £10. Do you really need 6 fans, though? What about using fewer? What about using a single small AC desk fan on a slow speed instead?
I haven't got pics to show you the cabinet but I would like two fans on each shelf and they would be 120mm I have a few fans lying around I will check the power requirements of them when I get home. I was also looking at getting these fans http://www.fractal-design.com/?view=product&category=4&prod=18 and they require 0.72W so if my maths is correct and I am open to correction I = P/V which is only 0.06 amps so I guess 1 amp per fan is over kill
Damn straight it is. Like I said previously, 3W per computer fan is an absolute maximum. 1W is an average value. Lower speed fans will need less current, too.
