I would like to make the mother of all scuba lights, as I am tired of my little Princeton Tec Miniwave LED. I've just modified it to use 3 x P4 emitters, but it's still pretty weak compared to what I want.
What I would like is a light with 7 emitters (hex grid pattern), either P7s or MCEs, driven to their brightest levels. They should be focussed to a large hotspot, say 15 degree beam, allowing the use of smaller reflectors, keeping the head's size within manageable limits. Heat is not an issue, as long as the heat sink that the emitters are mounted on is mated to the housing. The water will keep them cool. A thermistor could protect the emitters from being left on while not in the water.
The big challenge is the housing and ensuring that it is mated to the LED heat sink. I was thinking of lathing the whole thing into a titanium tube using a lexan front lens. The light should have a pistol grip, as I prefer those to lantern grips. I have no idea how best to machine this to the main body of the light, but I'd like it to be detachable for compact storage.
The lamp assembly needs to be interchangeable and as simple as possible. This would be useful as different emitter tints are better for different water conditions, and I could have multiple lamp assemblies for different conditions. The lamp assembly should incorporate the LEDs and their reflectors and screw into the head behind the lens, providing a solid mating with the outside case to ensure that heat can be bled into the surrounding water.
As weight is not too big a concern (bouyancy is not necessary so long as the light has a tether point where it can be tethered to my wrist or BCD jacket), there is no need to limit the number of batteries that go into the torch. 8 x 18650 batteries arranged in a 2x2x2 arrangement (long cylinder) should provide a nice 45mins of full-brightness run time for the P7s, providing that there is appropriate circuitry managing the power draw. I would need lots of advice on the best circuitry for such a light, as I have very limited knowledge in this area. The switch should be a reed switch, so that there is no need for a point of potential ingress.
Longer than 45 minutes run time should not be necessary although it would be nice. Dives are usually about an hour depending on depth, and you don't need the light for the first and last 5 minutes or so. I prefer easily accessible battery types, CR123A would be my first preference, but making a light that needed 16 of them is just silly. 18650 is my second choice as they are not too hard to find in a pinch, and I already have a good supply of them and a charger. Is this a good battery choice? Will 4x18650 work? How about 8xCR123A?
Does anyone have any advice on this crazy 6,300 lumen project? Should I be doing it myself or would I be better off giving my designs to a professional to make it for me? I have no access to CNC equipment, all parts and tools will need to be bought, so I don't know if this is a realistic project for me to even embark upon. Advice would be most appreciated!