[PSUBS-MAILIST] Emer Buoy brake and clear resin

[Alec Smyth via Personal_Submersibles]

Jon I think you'll find the heat output of COBs is much more concentrated.
Shackleton's lights are putting out 38K lumens, which come from a circle
maybe 1" in diameter. The COB is mounted to the aluminum housing using heat
conducting paste, and the housing has cooling fins. The glass is
borosilicate to deal with the heat. Despite all this, I only run them out
of the water for short periods. So I'm not sure, but I suspect the epoxy
might degrade in the immediate vicinity of the COB, and the COB itself
might be in trouble for lack of heat dissipation. The opposite approach
might also be interesting, using an off the shelf light with a large number
of smaller leds, if any can still be found. If you remember the Nuytco
lights, they were like a big flat frying pan of small LEDs. On Snoopy I had
some lights that were a little bit like that, a matrix of small LEDs.
Unfortunately I don't have a brand or a link, but here's a photo.

Best,
Alec



On Fri, Feb 21, 2025 at 10:31 AM Jon Wallace via Personal_Submersibles <
personal_submersibles at psubs.org> wrote:

> Hank,
>
> A few things I've gleaned in my quest to find the ultimate off-the-shelf
> submarine light.
>
> I've noticed that most off-road lights have moved to a tight spot pattern
> that is wide enough for a vehicle trying to illuminate 100-300 feet down
> the road but much too small/narrow for the 3-30 feet distance we would
> shoot for underwater. The Harbor Freight Road Shock Edge for example, at
> 3-10 feet distance has a concentrated spot diameter of about 10 inches with
> not much leaking light to the sides so totally useless for underwater use
> unless you wanted pinpoint light on a single seashell.
>
> As you described, the reflector can be removed to convert the output into
> an omnidirectional flood however doing so results in a noticeable
> illumination loss because almost all these inexpensive off-the-shelf LED
> lights get their high luminosity rating by concentrating the light via the
> reflectors. Your use of a light bar is an exception because you're starting
> off with a 20k-30k lumen output with reflectors and removing them still
> leaves you with a whopping amount of light. The 4 and 6 inch round units
> don't have that same capacity unfortunately, especially those running on 12
> volts. I did try the TigerLights without the reflectors (before expoying)
> and the intensity of the light seemed about as bright as a 75 watt house
> light bulb. A great omni-directional light pattern but just too dim.
>
> There's potential I think to build a hybrid using an off-the-shelf LED
> housing and replacing the PCB with a COB LED as described on the web site
> at http://www.psubs.org/design/lights/ that Cliff and Alec both use on
> their vessels. Installing the driver inside the vessel rather than inside
> the housing should make that a pretty easy conversion and result in a whole
> lot of light output. That will likely be my next side project.
>
> Jon
>
>
>
> On Thursday, February 20, 2025 at 12:22:20 PM EST, hank pronk via
> Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>
>
> Jon, this is great news.  When I make oil filled lights, I remove the
> reflector covers, the little cone things.  I find the scattered light is
> better than a beam.
> Hank
> Sent from my iPhone
>
> _______________________________________________
> Personal_Submersibles mailing list
> Personal_Submersibles at psubs.org
> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.whoweb.com/pipermail/personal_submersibles/attachments/20250221/74b35912/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: IMG_2768.jpg
Type: image/jpeg
Size: 118007 bytes
Desc: not available
URL: <http://www.whoweb.com/pipermail/personal_submersibles/attachments/20250221/74b35912/attachment-0001.jpg>