[PSUBS-MAILIST] Light Experiments

Mon Apr 17 16:27:20 EDT 2017

Alec,

Get my lamp glass here:

http://shop.dev-pein.de/Selbstbau/Glaeser/

They are not as brittle as you mention.

Br, Emile

Van: Personal_Submersibles [mailto:personal_submersibles-bounces at psubs.org] Namens Alec Smyth via Personal_Submersibles
Verzonden: maandag 17 april 2017 20:20
Aan: Personal Submersibles General Discussion
Onderwerp: Re: [PSUBS-MAILIST] Light Experiments

Hi Alan,

The borosilicate lenses in these parts are $17 each if that is a useful reference. I would recommend several spares, because while resistant to temperature they are VERY easy to break during installation or if you just look at them unkindly. On one light I'm on the first one, but the other light took three of them before I learned just how gentle I had to be.

Best,

Alec

On Sun, Apr 16, 2017 at 8:04 PM, Alan via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

Rick,

I should mention that I have now gone with a 36V system &

have some pwm dimming controlled buck boost LED drivers being

made for me. These could drive Cliff & Alecs light. So waiting for these 

& a reply on the borosilicate lens enquiry before I go any further.

Alan

Sent from my iPad

On 17/04/2017, at 11:39 AM, Alan via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

High Rick,

to insert the male subconn fitting it has to be turned 15 times as it

winds down fully in to the thread; so the wire would be twisted 15 times if

you went this way.

Yes the bolts go right the way through. This avoids tapping threads & bolts

seizing. It also has the advantage that I can have longer bolts out the back

that an attachment bracket can be bolted to.

The back section in the photo, has the led attached to it & an o-ring groove

to seal against the bore of the middle section. The base of the middle section

has an o-ring groove & the back section compresses this when the bolts

are tightened up. So two o-rings on this section. The top ring that clamps

the lens down on to an o-ring (also o-ring around the side of the lens) can

be made a larger diameter with a second set of bolt holes so the light can

be mounted in a recess.

As the back section is the main heat sink & mount for the LED I don't have

room for a bunch of twisted wires. The nozzle out back is designed so I 

can pour resin in to it, let it set, then coat the wiring about an inch up & 

the nozzle with silicone. Then I intend to mold a rubberised supporting

section over the silicon. It should work!

Pictures attached. 

Cheers Alan

<image1.JPG>

<image2.JPG>
Sent from my iPad

On 17/04/2017, at 10:08 AM, Rick Patton via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

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

<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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