I'm not sure that the supernova headlight is really guaranteed to put out less than 6v, but assuming it is and a 2v Vf on the LEDs, the website is calling for no more than 1/2 watt across the tail light LED. The supernova tail light has no heat sinking, but I'm not sure how much current it draws at 6 v. The LED at the website in the OP actually has a certain amount of heatsink built in. Granted, it wouldn't work for a headlight, but it would almost certainly work in this application.
Last edited by unterhausen; 12-26-14 at 11:10 AM.