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Thread: Heat transfer in divelight head

  1. #1

    Default Heat transfer in divelight head

    Hi all,

    After using a commercial (modded) canister primary (Halogen) for many years, a I was thinking of re-using the battery-canister \\
    and hook it up to a LED head ...

    I got a ALU head with suitable dimensions from Alunatec, a 7XPG-R5 module, a MaxFlex6 driver, and a (prolonged signal)
    Piezo to operate it.

    Although I had some initial ideas to cool the LED array & driver using Aluminum profiles, non of these worked out (mechanically).
    So, I'm in desperate need for some advice & new ideas on how to mate the LED/Driver support with the ALU housing (which
    would provide the best cooling when submerged).
    The inner-diameter of the housing is 50mm ...





    Has anyone tackled a similar problem, and succeeded in getting appropriate cooling/heat
    transfer to the external housing ?

    Thanks & greetz

    Patrick

  2. #2

    Default Re: Heat transfer in divelight head

    If you have (access to) a lathe, you can turn a 50mm diameter piece of alluminium that nicely fits in this housing and has the right height. This has worked for me on a greenforce HID head.
    If you don't have a lathe, you might be lucky that alluminium rods of 50mm fits nicely (here in europe, 50mm is a standard size). It will then be a matter of getting it flat and the right length and bore it out a bit on the backside to provide space for the driver.

  3. #3

    Default Re: Heat transfer in divelight head

    Hi jspeybro,

    Thanks for your suggestion ... Unfortunately I do not have access to a lathe, but
    I can always look for a workshop ... Aren't there some practical issues though with
    this approach ?... I.e. there's no easy way to adjust the height ... once the heat-sink
    is pressed-in, it will be very hard to remove again (if possible at all) ... and for sure
    some channels will need to be drilled to allow the wires through ... but that's only
    a minor problem.

    Thanks & greetz

    Patrick

  4. #4

    Default Re: Heat transfer in divelight head

    Rather then press fit you could use jbweld, at least this way you could adjust it a bit.

    Where are you located?

  5. #5
    Enlightened
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    Default Re: Heat transfer in divelight head

    Quote Originally Posted by patrickDM View Post
    Hi jspeybro,

    Thanks for your suggestion ... Unfortunately I do not have access to a lathe, but
    I can always look for a workshop ... Aren't there some practical issues though with
    this approach ?... I.e. there's no easy way to adjust the height ... once the heat-sink
    is pressed-in, it will be very hard to remove again (if possible at all) ... and for sure
    some channels will need to be drilled to allow the wires through ... but that's only
    a minor problem.

    Thanks & greetz

    Patrick
    Have a local machine shop turn something for you. You can calculate the length you need - so the optics fit in.
    You don't want an interference fit - just a push fit so you can slide it out as required. I use the cable to push the heat sink out (does not damage any joints - as it has a strain relief joining the sink to the cable.

  6. #6

    Default Re: Heat transfer in divelight head

    Ok, thanks for the help & suggestions ... I will contact some local shops & see what they can make.
    I will post some pictures once complete.

    Cheers

    Patrick

  7. #7
    Flashaholic* 350xfire's Avatar
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    Default Re: Heat transfer in divelight head

    You could always thread the insert and the body and screw in the insert.
    http://tlslights.com/ your source for quality affordable dive lights, Mag-lite conversions and weapon lights. Now a Federal Firearms Dealer.

  8. #8

    Default Re: Heat transfer in divelight head

    I guess that would work, although I'm not that sure if threading the inner of the 50mm dia housing would be very feasible ... it's
    somewhat deep(er) inside the head.
    I have a solution in my mind, I'll post some pictures if I find a CNC shop to make it ....

  9. #9

    Default Re: Heat transfer in divelight head

    Quote Originally Posted by patrickDM View Post
    I guess that would work, although I'm not that sure if threading the inner of the 50mm dia housing would be very feasible ... it's
    somewhat deep(er) inside the head.
    I have a solution in my mind, I'll post some pictures if I find a CNC shop to make it ....
    If your US based and can't find a local shop ping me.

  10. #10

    Default Re: Heat transfer in divelight head

    Ok, thanks for the heads-up ... I'm located in Belgium.

  11. #11

    Default Re: Heat transfer in divelight head

    Quote Originally Posted by patrickDM View Post
    Ok, thanks for the heads-up ... I'm located in Belgium.
    Shipping time and cost would suck ;-)

  12. #12

    Default Re: Heat transfer in divelight head

    Patrick, I live in Brussels :-) and have a small lathe, so I might be able to help you. If the inner diameter is really 50mm, I would need to go and get some alluminium though (I don't have a 55mm rod to start from at the moment). PM me if you are interested.

    Johan

  13. #13

    Default Re: Heat transfer in divelight head

    Will you use a colimator or reflector or that one is for video?

  14. #14

    Default

    Quote Originally Posted by patrickDM View Post
    Hi jspeybro,

    Thanks for your suggestion ... Unfortunately I do not have access to a lathe, but
    I can always look for a workshop ... Aren't there some practical issues though with
    this approach ?... I.e. there's no easy way to adjust the height ... once the heat-sink
    is pressed-in, it will be very hard to remove again (if possible at all) ... and for sure
    some channels will need to be drilled to allow the wires through ... but that's only
    a minor problem.

    Thanks & greetz

    Patrick
    It's low tech, but I've used excess cable pushed into the back I the housing through the gland to control where the heatsink fits. A snug slip fit is all you need with some thermal grease so don't worry about it getting stuck in. Worst case push it out from the back via the gland hole.
    Regards,
    Damien Siviero
    http://damiensiviero.com

  15. #15

    Default

    Where did you source the alunatec head from?
    Regards,
    Damien Siviero
    http://damiensiviero.com

  16. #16

    Default Re: Heat transfer in divelight head

    Sometimes Goolgle helps

    http://www.alunatec-shop.de/

    O bought one from him long time ago and they are simple but have good quality.

  17. #17

    Default

    I did google first but nothing came up on iPhone.

    Thanks for link.
    Regards,
    Damien Siviero
    http://damiensiviero.com

  18. #18
    Flashaholic* lucca brassi's Avatar
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    Default Re: Heat transfer in divelight head

    under DIY STORES ? maybe ?

  19. #19

    Default Re: Heat transfer in divelight head

    Hi all ..

    Sorry for not replying the questions earlier, and thanks for the offered help & tips ! ... somehow I stopped receiving mails notifying me about new entries
    in this thread
    Indeed, I got the head from Alunatec .. The quality seems pretty good (although I'm yet to take the housing under-water) ..
    I also contacted them about a heatsink-solution I designed (basically, an expanding slug), and the parts are currently under way ... I'll post some pictures
    once they arrive, and some follow-up for the completed head.

    Cheers & thanks, Patrick.

  20. #20

    Default Re: Heat transfer in divelight head

    Forgot to reply to Delphinus question ... I'll be using a Polymer Optics lens assembly, the 12degree version



    I also have the Kathod 10 degree lens, but from what I've read in other threads, it seems the bundle is nowhere near that
    figure (could well be the same for the Polymer Optics though).

    Cheers Patrick

  21. #21
    Flashaholic* DIWdiver's Avatar
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    Default Re: Heat transfer in divelight head

    I used the Polymer Optics lenses in my light. I was very disappointed in the beam quality - lots of rays and other irregularities. They aren't too bad when 6 of them are combined, but not at all what I expected. My next light will have an Ahorton aspheric.

  22. #22

    Default Re: Heat transfer in divelight head

    Hi DIWdiver, thanks for the tip ...

    I guess an aspherical lens would indeed be better, but in that case (i.e. with the alu-housing I'm using) I would need
    to find one (or have one made ?) with a correct sized flat bevel ...
    the bevel should also have a reasonable thicknesss (max intended diving depth 80-100m + safety factor).
    Any ideas where to find such designs ?

    Cheers

    Patrick

  23. #23
    Flashaholic* DIWdiver's Avatar
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    Default Re: Heat transfer in divelight head

    Actually, you need to put a flat plate in front of the aspheric, and that should be what is depth rated. The aspheric should not see pressure.

  24. #24

    Default Re: Heat transfer in divelight head

    Ha, ok, understood ... for this particular head it won't be an option then ... with the designed-heatsink (hope to receive it later today) there's no
    sufficient space to place the aspheric at the correct focal length.

  25. #25

    Default Re: Heat transfer in divelight head

    Just a quick update on the heat-sink I designed ... The o-ring keeps the assembly together, and tightening the hex-bold increases the diameter of the slug, allowing
    a (very) snug fit. Note that the heat-sink is still missing the mounting-threads for the led assembly & the holes for the supply-wires.

    Cheers Patrick




  26. #26
    Flashaholic* 350xfire's Avatar
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    Default Re: Heat transfer in divelight head

    The bad thing about that is that you will have localized hot spots. The middle LED may fail since it may run hotter due to the hole below it. Also, because you have no really good contact with the wall of the head, the heatsink will eventually be saturated with heat that cannot escape.

    Cool idea though.
    http://tlslights.com/ your source for quality affordable dive lights, Mag-lite conversions and weapon lights. Now a Federal Firearms Dealer.

  27. #27

    Default Re: Heat transfer in divelight head

    Hi 350xfire ... thanks for your feedback ...

    I'm indeed a bit worried about the hotspot in the center, but I'm still hoping the alu-pcb will be able to even this out a bit ....
    the hex-nut is flush with the rest of the heatsink (at maximum diameter) so the non-covered area is pretty small ... but it's there nevertheless.
    The contact though with the wall is pretty solid ... the o-ring is just there to keep everything together ... once the bold is tightened (and the HS diam. can
    increase beyond the inner-diameter of the housing per design), the o-ring is fully compressed in its groove, and there's full (except for the grooves off-course)
    metal-to-metal contact (including cooling-paste).

    Cheers

    Patrick
    Last edited by patrickDM; 02-17-2012 at 02:13 PM.

  28. #28

    Default Re: Heat transfer in divelight head

    don't you have enough space inside for the batteries? it looks big.

  29. #29

    Default Re: Heat transfer in divelight head

    No, it's not that big (maybe just seems like that in the pictures)... total length of the head is 7.5cm ... inside-depth (i.e. behind glass) is only 5cm ... the heast-sink is
    approx. 2cm thick ..
    The rest is taken up by the led-assembly, lens, driver, and leaving some space to work with (supply-cable, piezo-cable).

  30. #30
    Flashaholic* lucca brassi's Avatar
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    Default Re: Heat transfer in divelight head

    Good work ! - nice heat transfer , but middle led should be OFF , OR you have to put in middle cooper cork instead instead of that tube (same thing as Intel processor heatsinks .

    Don't worry abour wires , you could drill hole somewhere between leds where is no Cu trace on AlPCB. Important at leds is that they have good thermal transfer in range of few milimeters from semiconductor joint ..... Al PCB also even more distribute heat equally but not to heat neighbours leds.

    When wou made next time heatsink like that ...it is very good design , but you don't need to cut segments through , enough is only 1/2 - 2/3 max of cylinder only to transfer and distribute heat equally . Be sure that heatsink is inverted U hollow shape not full . (you don't want to collect and store heat in mass (Q=m*cp*dT ; A=Q*t)
    ------------------------------------------------------------------------------------------------------
    OOT : (I work with some very special welding machines (hot stacking ) these days at work , I'll put energy of 2500W @ 1000A @ 55ms (constant power mode) in segments with cca 1g turned with enlameted wire 0,22mm (1turn/2turn ) whole thing have diameter 15mm and high 6mm with 6 these segments.
    (carbon commutators - that on picture is big and heavy one
    Point of that is that with special approach it is possible to transfer pretty quick .
    Last edited by lucca brassi; 02-18-2012 at 02:44 AM.

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