Air flow for cooling ballasts.

I need opinions on where I should mount a 40mm fan.

The box I built to hide the Workhorse 7 ballasts is vented but it still getting a little warmer than I would like so I'm going to install a fan I literally ripped out of a busted laptop.

My question..

Would it be better to install the fan so it pulls hot air out of the box? OR

Should I set it up to blow cool fresh air into the box?

 

I would say both, on one end run the fan pulling air out and on the opposite side have a fan blowing cooler air in.

 

i mean if you can get two fans.

 

I would have it pull the air out. If I had two I agree with skurious.

 

That would be optimal but I only have the one junk laptop and it only had the one case fan.

 

i would suggest have the fan mounted to the top of your box, blowing air out because hot air rises.

 

One fan, mounted on top and a series of 1/8" holes drilled in rows on the slide door is more than enough. The lights have been running for over 4 hours now with the box closed and they are just warm to the touch.
I sealed the intake side of the fan real well so it can only pull air from inside the box. I used velcro just in case it didn't work out and had to be moved to the inside of the box.
I also used an old cell phone charger for the DC power since I had one on hand that had the exact output I need to run the little fan. I didn't want to have another thing to plug in so I soldered 14 gauge wire to the prongs on the charger, cut a hole in the side of the box just big enough for them to go through and hardwired them to the power on the ballasts. So the fan will be running anytime the lights have power to them.

Pics of the hole set up will be up later on my 90 build thread.

 

Congrats on the solution

 

Thanks. The wife has takin to calling me Tim Taylor LOL.

 

You should blow cold air in. Cold air is denser and a fan will not move as much air pulling hot air than it would moving cold air. Putting cold air in assures cold air around the ballast and will assure a better heat transfer.