[PSUBS-MAILIST] LED Lights

[Alan James via Personal_Submersibles]

Hi David,you can get really simple with these LEDs & run the emitter straight fromthe power source. The light intensity fluctuates with the heat, but with thelight intensity we are talking about, it might not be noticable. The trick wouldbe picking a voltage low enough so that it didn't get too bright & burn out the emitter when it warmed up. Next step up in simplicity is to just stick a resistor in series, & there arecalculators for this on line. I am wondering if a thermister instead of a resisterwould be a good idea, as this would restrict the current as the unit heated up.It may be a good option for running out of water if the thermister values were right.The beauty of this system would be that you would only have 2 componentsthat you could damage by heating. The down side is a reduction in efficiencyover a buck driver type system.Cheers Alan
      From: Seaquestor via Personal_Submersibles <personal_submersibles at psubs.org>
 To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
 Sent: Tuesday, July 28, 2015 3:10 AM
 Subject: Re: [PSUBS-MAILIST] LED Lights
   
 Hi Cliff, maybe Phil could chime in on his led he demonstrated at his shop for use on the deep workers. It had only a flexible membrane over the oil compensated led housing. I think his design is about as compact as you can get, and I recall it had now fins, but run a voltage up to around 200+ volts. Seems to me that simpler the better, is the idea here. For me I will testing my design hopefully next week. with 4 leds, wired for high and low. Based upon alum cost, machining, leds and  subconscious connector I'm coming in around $500 for each light. Cost may drop with multiple units. But one off is always more expensive.
Best Regards,David Colombo


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-------- Original message --------
From: Cliff Redus via Personal_Submersibles <personal_submersibles at psubs.org> 
Date: 2015/07/26 1:28 PM (GMT-08:00) 
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
Subject: Re: [PSUBS-MAILIST] LED Lights 



For anyone that has a large LED or halogens on their boat, can you share your experience on narrow beam vs flood lights.   Building a LED housing to be low profile to fit in a FRP recess is going to be difficult with a reflector to get a narrow beam.  As an example, a typical reflector size for a Vero 29 is 110mm (4.33") diameter and 67mm (2.64") deep.  This is massive and you still need housing and heat sink fins.
I am wonder if we really need a focused light or is a flood light adequate?
Cliff
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