<div dir="ltr">Thanks Alan and Chris<div>much appreciated and I can't imagine building a sub without this group!</div><div><br></div><div>Rick</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Sun, May 13, 2018 at 12:53 PM, Cliff Redus via Personal_Submersibles <span dir="ltr"><<a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><font color="#000000" face="Times New Roman" size="3">
</font><p style="margin:0in 0in 10pt"><font face="Calibri"><font size="3"><font color="#000000">Rick, based on my experience, I agree 100% with your electrical
guy.<span> </span></font></font><font color="#000000" size="3">The problem is any of these high
lumen Led arrays will quickly overheat and destroy themselves if you cannot move
the heat away from the array. The LED lights I have will work continually even
when not submerged.</font><span><font color="#000000" size="3"> </font></span><font color="#000000" size="3">They are housed in
6061-T6 aluminum case and are 1-atm air.</font><span><font color="#000000" size="3">
</font></span><font color="#000000" size="3">As Alan mentions, the key is having the arrays securely mounted to an
aluminum base with heat conducting grease.</font><span><font color="#000000" size="3">
</font></span><font color="#000000" size="3">This aluminum base has to be designed to conduct the heat away from the
array and into the cooling fins. Fins have to be designed to convect heat away
from heat sink either by forced convection or natural convection when not submerged.</font><span><font color="#000000" size="3"> </font></span><font color="#000000" size="3">The problem you are having is the mineral oil
that is surrounding the array just cannot dissipate the heat fast enough.</font><span><font color="#000000" size="3"> </font></span><font color="#000000" size="3">If you repeated the experiment with only one
change, mounted the array to a finned heat sink, it probably would have worked
just fine.</font><span><font color="#000000" size="3"> </font></span><font color="#000000" size="3">As Alan mentions you need a
constant current driver.</font><span><font color="#000000" size="3"> </font></span><font color="#000000" size="3">Also I have had
better luck with higher quality arrays like Bridgelux Vera 29.</font><span><font color="#000000" size="3"> </font></span><font color="#000000" size="3">These are cheap at Digikey.</font><span><font color="#000000" size="3"> </font></span></font></p><div><font color="#000000" face="Times New Roman" size="3">
</font><span style="line-height:115%;font-family:"Calibri","sans-serif";font-size:11pt"><font color="#000000">If you don’t want to do the engineering around
designing the LED light system, Hank’s approach works.<span> </span></font><font color="#000000">Buy and off the shelf light that mates with
your electrical system and hydraulically pressure compensate</font></span></div><div><span style="line-height:115%;font-family:"Calibri","sans-serif";font-size:11pt"><font color="#000000"><br></font></span></div><div><span style="line-height:115%;font-family:"Calibri","sans-serif";font-size:11pt"><font color="#000000">Cliff</font></span></div></div><div class="gmail_extra"><br><div class="gmail_quote"><div><div class="h5">On Sat, May 12, 2018 at 3:51 PM, Rick Patton via Personal_Submersibles <span dir="ltr"><<a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.<wbr>org</a>></span> wrote:<br></div></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div class="h5"><div dir="ltr">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.<div> <div>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.</div><div><br></div><div> 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!</div><div> </div><div>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.</div></div><div><br></div><div>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!😂</div><div>Rick</div><div>The fissures stopped spewing lava two days ago so will hope for the best but looters are having a field day!</div></div>
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