LED upgrade question

I have an underwater light that uses a PAR 36 size bulb (GE 4515, I think) that I would like to upgrade to LED. There are a few aftermarket bulbs available (Trilliant 36 is one: http://www.grote.com/product.php?product_number=63861-5 ) but they don't appear to be much brighter than what I already have and don't produce the kind of spot beam that I need for scuba diving. It was suggested to me that many people make their own LED bulbs these days, and I could probably do much better going that route. Does anyone know of someone who is very good at doing this, and point me in their general direction?? Thanks.

narrow beam like you looking for, only possible with aspheric lens with led, today at least, there are narrow lenses and reflectors, but they are not narrow enough for scuba, you will light up everything around and every litlle particle in water will reflect that light. unless you dive in place with cristal clear water, you wont get much use out of those lights.
4515 is a stage light with very narrow beam and no spill, i don't know of any way to do the same with led besides aspheric lens. plus you have a need to cool the led, in a right place. so converting a halogen light into led and to have proper beam will be more expencive than getting scuba light that already build around led, have you tried Underwater Kinetics AquaSun e.L.E.D.

Hi, thanks for getting back to me on this! Yeah, I vaguely remember when I built my light 10 years ago, that I had to look around for the best sealed-beam that would provide the narrow spot pattern that was necessary. I'm over-driving that 6-volt 4515 bulb with 11 volts (32 rechargeable AA batteries in a series-parallel arrangement) but I've been able to get away with it for maximum intensity. Cooling wouldn't be a problem because the lantern case is thick cast aluminum, but I definitely know what you mean about not lighting up everything in the water around me, and I don't know anything about designing lenses for that application. I saw one of those UK Light Cannons on a night dive a few years ago, and it seemed that the light color temperature was better suited to low-visibility conditions, and I've noticed that the LED flashlights have the same blue-white light, which would be ideal if the beam could be focused enough.

I wouldn't mind spending a few bucks to get something like the aspheric or very narrow lens you described, if it is possible (anyone-give me any more input about this??) and would end up being brighter and give better battery life. Just need something the same diameter as that PAR 36.

alpg88 said:

narrow beam like you looking for, only possible with aspheric lens with led, today at least, there are narrow lenses and reflectors, but they are not narrow enough for scuba, you will light up everything around and every litlle particle in water will reflect that light. unless you dive in place with cristal clear water, you wont get much use out of those lights.
4515 is a stage light with very narrow beam and no spill, i don't know of any way to do the same with led besides aspheric lens. plus you have a need to cool the led, in a right place. so converting a halogen light into led and to have proper beam will be more expencive than getting scuba light that already build around led, have you tried Underwater Kinetics AquaSun e.L.E.D.

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well metal housing doesn't mean much if leds are not sitting on it and transfering heat directly in the body, which than cools by surrounding water. you will need to redesign the light itself a bit, one sst90 would be enough driven at 8-9 amps 2000 or so lummens, with temp 6000k or so, but you'b need to make a solid heatpath to the body, and use aspheric lens, search for aspheric mods, you will see planty of info on it, but remember cooling for led is critical, the less heat resistance points the better, star is a weak link, the best solution to solder bare sst90 onto copper heatsink directly.