Dedicated psu for hotswap?

[E-Zombies]

Hey guys quick question, i recently came into a two Bay hotswap enclosure, and 5 older 120-500gb harddrives. But my rig is about capacity for my PSU. I have a 300w laying around. My question is, can I use the 300w psu solely for the hotswap? Also plan on leaving it powered up, so would having the harddrives already running interfere with my computer, assuming the drives in the hotswap are not vital (not boot drive)?
Would there be a difference if one WAS my boot drive?

There's no real upgrade factor for my rig I'm just tinkering with free stuff lol.
Thanks in advance.

 

[faalin]

the two wires marked in the picture, take two other wires and splice into these two and connect them to the other PSU's green and black wires. When you turn on the primary PSU it will start the secondary one.