I had the exact same problem with a far less powerful light (one of the planetbike 3 led ones). That problem was solved by remounting the display unit of the computer on the stem, so it was slightly behind the light. I guess I just got it out of whatever interference pattern the LED was putting out. I do not know whether it would work with that powerful of a light, but it's worth a shot and would take about 2 seconds to test out. Try different configurations, and you may find one that works.