SPCR

I'm trying to run a DIY external HDD box, and i want a fan to cool them.

1) I can use a regular AC mini fan, but that's a little bit over kill.

2) I decided hey, computer fans will do the trick... but powering them is problematic.

then I remember I have a bunch of those outlet USB thing, can they power fans?

i googled and found that people have been able to power computer fans with USB cables... however...

the fan is 12V @ .15A

the USB outlet unit is 5V @ 500ma = .5A

so my question is that will i burn the house down if i run the fans for a long period of time? i mean wattage wise the unit can handle the fan (5 X .5 = 2.5W which is more than 12 X .15 = 1.8W), however they're at different voltage... any electrician out there?

I am not electrically inclined but I think I ended up using an old cell phone charger that I accidentally broke the charging tip and just spliced the wires by twisting them and wrapping them in electrical tape. On a whim, I bought something similar to this at my local Fry's Electronics.

Cooler Guys AC to molex adapter

Thermaltake has both an 80mm and a 120mm fan that work off of a USB connector. They both have adjustable speeds. Will that help?