I found a 12v power cord, so now each fan has a 12v power supply. But, even still, it wasn't enough. I think they have a low CFM.
This will do it: http://smile.amazon.com/dp/B005KMTYFK
Wow! That's a big one and would certainly move the air around! But it wouldn't fit between the light bulbs & the vent hole the way it's currently set up.