I just hooked that HID up to my bottle battery with a regular old switch.
I used a 14.4v battery - that was a mistake. I had to put a voltage regulator in line because a 14.4v battery puts out in the neighborhood of 15.7v for a while, and it killed my first HID (trailtech fixed it for me).
I set the regulator at 12.6v and it's been running all winter just fine. I think if I'd started with a 12v battery instead I'd have been fine and a little richer.