Originally Posted by Frick
Still a good idea with the cap/inductor (which incidentally is a filter, I don't remember exactly what that kind of filter does though :P).
The cap smooths fluctuation in voltage and the inductor smooths the current. Just be careful where you put that cap because you may introduce resonance between the cap and the inductor. Your best option would probably be to ignore the inductor just go with a small 20-30v cap. I suspect current smoothing won't be necessary. Nothing too big for the cap though, keep in mind that cap has to charge when it's switched on. All in all, you're driving fans, not circuitry so it probably isn't necessary.