I am adding one 24" light bar to the front of my Z8 and a smaller 7" to the rear for a backup light and for loading a trailer at night. While waiting on the mounting brackets to come in I decided to test run the 24" to see just how much light it puts out and what the actual amp draw was because I had assumed (and you know what that does) I could just use a Watts-to-Amps converter to get an answer.. which was what I based my size decision on for the front as the converter said it would pull 9.6 amps and I needed to stay under 10-amps. Well, using my amp probe that can measure DC draw, the 24" only pulls 4.6 amps. Had I known this, or it was listed on the information, I could have gone with a larger one. Oh well food for thought. This one will serve the need and leaves room for more accessories...lol.
So apparently there is another formula or factor to consider for load calcs when dealing with LEDs.