DIY Outdoor Event Searchlight Answered
In am interested in building an outdoor event searchlight or advertising spotlight that you might find at the opening of a Hollywood premier. Basically, an intense beam of light projecting miles into the sky to attract people to a location. I searched Instructables and found some projects for stage spotlights but nothing like an outdoor searchlight. I did locate some complicated Carbon Arc and Xenon lamp projects but these involved a lot of expertise in electrical engineering! I am a novice but I am comfortable with basic "household' wiring.
With that said, my thought was to try using 7 or 8 (maybe more) 55w car Xenon HID (6000k range) headlights as my light source. Xenon HID produce three times the light output as standard halogen headlamps (3000 lumens vs 1000 lumens) and require less energy.
The "conversion kits" come with the igniter module and inverter ( ballasts) which reduces the amount of electrical wiring. At this point, the power source could be to use 110v household AC current and then, using a AC to DC converter, turn it into DC voltage and let the "conversion kit" components change it back to AC. From what little I know, Xenon HID take about 25,000 volts to start a Xenon bulb and then 80-90 volts to keep it operating. During operation the AC ballast frequency is usually in the 250 to 450 Hz range. Each bulb draws around 6.5 amps at startup and then stabilizes at around 3.8 amps.
Next, I would place the bulbs into the center of a Ellipsoidal Reflector to direct the light skyward. Basically, the 7-8 Xenon HID bulbs would be secured to a piece of sheet metal and then surrounded by a reflector so it would be like a VERY large headlight pointing into the sky. In one of the YouTube videos, the guy used a trashcan as the housing. I am not looking for something this large but similar in concept. I located an Ellipsoidal Reflector on Ebay for about $55 and then I might just build a housing around it.
But would the reflector be enough to concentrate the light into a strong beam? Or, would I need to have some sort of lens to focus the light?
If anybody has constructed something similar of if you have any pointers on what to do, please let me know.