If the lights plug into your
PSU, then they draw DC current at a max of 12Volts, I belive, power that comes from a socket in the wall is AC and at 230Volts is the UK or 110 in the US of A, either way you would need a converter. Or you could fit a second
PSU, plug the lights into that and rig up a switch to turn it on/off independantly of the main PC.
Favu.