Computer fan ventilation

So I am building a 150 watt HPS grow box out of a huge cardboard box, the inside of which I have painted white. I'm only looking to grow 2-3 plants so the space seems perfect (~2x2). My question is about making efficient ventilation.

I was going to build a PVC tube to run just above the light with holes drilled to suck the heat out. Obviously the one end would be sealed with the other end containing some kind of fan, with a mesh covered hole at the bottom of the box just at stem/root level. The best thing I could come up with is a fan I jacked out of an old computer. The problem is that it uses a twelve volt current, and Im not sure how I'm going to work this out as I want to wire it in so that it kicks on with the timer....

PS. do you think I should supplement the light with CFLs?

Somebody has got to know how to wire one of these in...

i've heard you just use an old phone charger (or similar transformer) thats rated close to the fan voltage and amprage. i think... sorry but thats alls i know. i use inline duct fans.

yes an old phone charger or something to that effect will work. PC fans are 12V DC so just look on whatever you are going to use and it will tell you the output power. Black is ground, red or yellow is hot. I have done this many times and is perfectly safe.

Appreciate the help. I figured that might be the best approach, trying to save some $ by rigging my own setup, so I'll look thru my old crap.

Keep an eye out for my first ever grow log!

Yea u can also use an old computer power supply, basically u need an AC to DC converter and your fine. i use and old computer, and fans with built in thermometers. I use a fan program that tells me all the temps and what rpm the fans are spinning at.

Its not difficult at all to wire a PC. You can use either a AC to DC 12V transformer, a cell charger (as close as 12V the better) or a PC power supply. You just need to connect the + wire to the + terminal of the fan and the same with - wire and terminal.

But i wouldnt advice you to use PC fan if you are using ducts. PC fans gives very little static pressure, often to little to be able to pull or push through a duct keeping a decent airflow. If any, you need to connect two stacked fans in order to get enough pressure for the task. An exhaust bath ban is often an easier and better suited alternative, and that may be cheaper than the PC fans plus the transformer. Very often, bath fan with same CFM rating than a PC fan gives double the static pressure, due the larger thickness.

There are too axial fans (like PC ones) working from mains AC directly that are thicker than PC fans (38mm and still more), gives more static pressure and dont need wiring. But they are usually very noisy.

old phone charger works great just make sure they are close to same voltage fan and charger i have one like that on my flowering chamber