I would get a Sam's HID off of eBay or BST, yank the battery and make your own higher quality cord. Can get the parts from radio shack for pretty cheap. The lumens would be higher and the current draw would be less than half.
Sorry if this is above your price range but the quality is probably much higher than the others:
http://www.magnalight.com/pc-1711-2...-cord-and-cigarette-plug--12-24-volts-dc.aspx