[PSUBS-MAILIST] LED lights

Sun May 13 13:47:15 EDT 2018

Thanks for your input Alan! Since I DON'T understand anything about
electricity at all, this has been a real frustrating process and I have
been very tempted to just go back to the plans for the K-350 and use the
tried and true incandescent bulbs in a one atmosphere housing but I haven't
given up quite yet.
We just had a new fissure pop up last night, I think number 17 after a
couple days of all fissures just just off gassing with no lava. Wish I had
the sub done for when it reaches the ocean and it will.
Rick

On Sat, May 12, 2018 at 7:23 PM, Alan via Personal_Submersibles <
personal_submersibles at psubs.org> wrote:

> Rick,
> is your buck converter constant current, constant voltage?
> Needs to be constant current as when the LEDs heat up they draw more
> current & can burn themselves out.
>    At a certain voltage the current can be kept under control but I've seen
> graphs where just 1 more volt will cause the current to really climb.
>    You need to screw the LEDs down hard on to a heat sink with a thin layer
> of heat sink paste between. They will burn out if this is not done
> properly.
>    I have been told that people drive the LEDs too hard & that competing
> manufacturers tend to over rate their lights; so it might pay to drive
> them at
> 80W rather than 100  W.
>    I have glass lenses & no compensating oil. When I tried an acrylic lens
> it
> trapped the heat in! You can feel the heat pour out the front with the
> glass
> (pressure & heat resistant borosilicate) lens.
>    I am using buck boost constant current drivers with dimming that I had
> made
> up for me in China. They work well but there are a few things I want
> changed.
> One of the components needs heat sinking as it gets too hot when the LED
> is on high power; the on off switch is on the pcb board & I need it to be
> remote.
> It is really fiddly taking off this switch & soldering an extension wire.
> Also
> the default mode for a disconnected / broken wire on both the dimmer & on
> off
> switch is that the light stays on & this would kill the light if a wires
> soldering
> broke when the light was out of the water.
> Will get them to change these things some time. If you get desperate & want
> some of these drivers I will get on to it & order a few more. Mine are
> 12-54V
> buck boost constant current with dimming.
> Glad you haven't had a volcano pop up in your garden. Have been watching
> the news footage & it looks pretty spectacular.
> Cheers Alan
>
>
>
> Sent from my iPad
>
> > On 13/05/2018, at 8:51 AM, Rick Patton via Personal_Submersibles <
> personal_submersibles at psubs.org> wrote:
> >
> > I am still trying to come up with a viable working LED light system and
> I think I have it boiled down to cheap arrays? I have a friend helping me
> that understands electricity a lot better than I do and he seems to think
> it's a heat issue, not dispersing it quick enough.
> >
> > I am using a 10,000 lumen array that is about 1 1/2" square and costs
> $2.75 each and made in china. Well, you've herd the saying, you get what
> you pay for? These are rated for about 100 watts and like to see around 34
> volts so were running them threw a buck booster? and dialing them down to
> that from about 38 volts and then running them threw a PWM and then to the
> array.
> >
> >  I at first was putting them in a housing that I had fabricated for them
> using a strain relief fitting to run the power cord threw as the housing is
> full of mineral oil then setting the housing in a 5 gal bucket of cool
> water and they are still burning out so I tried just hanging an array by
> it's wires into a container of mineral oil and still only lasting a couple
> of minutes so I got a thin cold pack from the freezer (without telling my
> wife of course!) and sandwiched the array in it thinking that that would
> eliminate any questions of the heat dissipation theory and it still only
> lasted a minute!
> >
> > My friend is still insistent that its a heat problem and that the thin
> layer of plastic that holds the frozen stuff in is enough to keep the array
> from seeking the relief that it needs before melting down which I don't
> agree with. He says he can hang an array by it's wires in a bucket of tap
> water for a number of hours with no issues and that water disperses heat
> much faster than oil.
> >
> > Sorry for the long post but I felt it necessary to let you guys know
> exactly what I am doing for better input. I want to put this behind me so I
> can get on to the next thing! It would be helpful to hear from those who
> are using a small high luman LED array as to what you are using and where
> did you buy it. PS: I snuck the cold pack back into the freezer unnoticed!😂
> > Rick
> > The fissures stopped spewing lava two days ago so will hope for the best
> but looters are having a field day!
> > _______________________________________________
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>
>
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