[PSUBS-MAILIST] Light Experiments

Sun Apr 16 18:08:21 EDT 2017

Hi Alan,

Thanks for the picture.
The size housing you are using is kinda what I wanted to go with as well.
Not sure what you mean about screwing something in 15 times. From the top
view picture you sent, looks like the front head/lens is held on against a
sealing surface with 6 Allan head bolts that go all the way threw the back
plate so I assume that the back plate is threaded and screws on against an
0 ring or something?
 If that's the case, can't you drill and tap the back and put a sub-Conn or
strain relief fitting in and allow just enough length of wires to protrude
inside just enough to connect the LED wires to it before attaching the
lens? Do you have any pictures of everything inside the housing by them
self's?

Rick

On Sun, Apr 16, 2017 at 10:39 AM, Alan via Personal_Submersibles <
personal_submersibles at psubs.org> wrote:

> Hi Rick,
> The light in the photos is mk 1 or 2. It didn't have oil in in those
> photos.
> Funny but the oil bubble & the temperature sensor had no effect on
> the light coming out.
>  The latest version has a conical lens machined in it & hides the
> attachment
> bolts for the LED.
> Still a work in progress as I have just made enquiries regarding pressure
> rated borosilicate glass lenses. This light is 85mm D x 54mm long.
> (excluding
> wiring nozzle) In the attached photo I have just temporarily siliconed
> around
> the wires for the test. I do have 8 subconn male & female connectors & was
> thinking of tapping a hole for the male connector to fit. The only problem
> is
> how do I connect the wires? My two LED wires are either side of the LED &
> come
> down two separate angled holes & meet in a central 8mm hole. I would need
> to fit the LED then attach the LED wires to the subconn wires & twist them
> 15
> times to thread in the subconn fitting. The subconn wires are very stiff &
> it
> just wasn't going to work without a large amount of room for twisted wires.
>    I have some ideas for potting the wires that I will try & test.
> The housing diameter was dictated by stock material sizes but works out
> well.
> I have machined the cooling fin slots in to the bolt holes to give the
> fins a bit
> more depth.
> Alan
> [image: image1.JPG]
>
>
>
>
> Sent from my iPad
>
> On 17/04/2017, at 5:43 AM, Rick Patton via Personal_Submersibles <
> personal_submersibles at psubs.org> wrote:
>
> Alan,
>
> Do these pictures have the silicone oil in them? Do you have any side and
> back shots of the housing and other data regarding the housing like wall
> thickness and what fitting did you use to get the power out of the back and
> such?
>
> Rick
>
> On Sat, Apr 15, 2017 at 6:33 PM, Alan via Personal_Submersibles <
> personal_submersibles at psubs.org> wrote:
>
>> I put a temperature probe inside the housing of my 80W LED light.
>> The probe was up against the acrylic lens, as I was concerned about
>> what temperature the lens was seeing on the inside. The lens is 10mm
>> away from the LED.
>> The LED manufacturer told me that on normal LEDs the temperature
>> out the front of the LED can be 338F (170C) but my flip chips should
>> run cooler.
>> Briefly; when run at 30W in water they stabilised at 257F after 5 minutes.
>> At 45W they stabilised at 280F after 5 minutes. I stopped upping the amps
>> at this stage.
>> Next experiment, I filled the housing with silicone oil.
>> At 45W it hit 116F in 4 minutes & temperature stabilised.
>> At 76W it hit 139F in 6 minutes & stabilised.
>> So oil has massive advantages in lessening temperature on the lens,
>> maybe because it is a buffer from the radiant heat & also transfers the
>> heat
>> out through the housing quicker.
>> Greg your thoughts would be appreciated on this; I am thinking that
>> without the
>> oil the acrylic lens would see temperatures at which it is formed
>> especially
>> if I went up to 80W. Although the outside of the lens was cold there
>> would be a
>> temperature transition across the thickness of the lens & it would be
>> considerably
>> weakened. I am building to 500ft, so it would potentially see 250 psi in
>> operation.
>>    At this stage I haven't made up my mind whether to go with a
>> borosilicate lens
>> or oil fill with an acrylic lens. I had a large bubble & it would be hard
>> to eliminate
>> all bubbles in the oil filling process.
>> Will try & attach photos.
>> Alan
>>
>>
>>
>>
>>
>>
>>
>> Sent from my iPad
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>>
>>
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