[PSUBS-MAILIST] led

Tue Dec 29 22:05:12 EST 2020

Alan

I don't have facebook but my wife does. not being familiar with the format,
how would I look up your lights?
my cobs are 1 13/16" X 1 9/16" and about 1/8" thick. What approximate size
are yours and how does a flip chip differ from a regular cob? have you had
any burn out from getting too hot?
I am using a dielectric oil in my light housings called Marvel Mystery oil
to get around the pressure differential problem but it has a slight color
to it so will have to see how the light is effected by that and if it gets
any worse from being heated. 10,000 lumens is a lot of light so
hopefully they will still be bright enough. I am using oil compensated
thrusters as well and I do have small bladders that can expand and contract
with heat.
I bought heat treated lenses from Mcmaster Carr but they were about $22
each and they are glass instead of acrylic.
Rick

On Tue, Dec 29, 2020 at 2:55 PM Alan James via Personal_Submersibles <
personal_submersibles at psubs.org> wrote:

> Hi Rick,
> I posted a couple of pictures of them on the psubs Facebook page. Not sure
> whether you are on there or not.
> The lights are about 7000lm. Leds are usually around 100lms per Watt. They
> are rated a bit more but I am under driving them as they get too hot
> otherwise.
> They are chip on board leds. A technology called "flip chip". I bought
> them off the manufacturer in China.
> Marine anodizing is thicker, 25 microns. You can get more corrosion
> protection with hard anodizing. It affords extra protection against
> galvanic corrosion.
> The buck boost drops or increases the supply voltage to the voltage
> required for the led. In my case I can connect the driver to anything from
> 12V to 60V and it increases/reduces it to the 36V required  by the led. The
> driver should also be CC (constant current) as the resistance of the led
> drops as it heats up & allows a lot more current through.
> I didn't want oil as its messy, & hard to get all the air out. It can also
> discolour with heat. It's used successfully by lots of people. One
> technique with oil filling is to have a hose fitting out the back of the
> light with a pvc tube attached that the wires run down. The tube is
> pre-crimped so that it collapses easy under pressure & equalises the light
> fitting.
> I am using glass lenses because acrylic holds the heat in.
> Alan
>
>
> On Wednesday, December 30, 2020, 10:37:56 AM GMT+13, Rick Patton via
> Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>
>
> Hi Alan
>
> Couple of questions
>
> How many lumens are your lights
> What is the source of the light? COB?
> How does marine anodizing differ from just regular anodizing and why do
> you think that is necessary?
> Is the Buck Buster/LED driver only needed to be able to dim?
> Why did you want to avoid oil?
> Rick
>
> On Tue, Dec 29, 2020 at 10:59 AM Alan James via Personal_Submersibles <
> personal_submersibles at psubs.org> wrote:
>
> Rick,
> I spent a lot of time on my light project, initially looking for & buying
> lights & housings on line, that I could adapt.
> I ended up buying 70W leds & making my own housings. The housings I had
> marine anodized. I had to get an led driver designed & built in China, as I
> wanted dimming. The driver is a constant current step up, step down (buck
> boost) that takes a 12-60V input.
> I had the lenses made up in China; 20 for about $2- each. The units were
> tested to 1000psi. Have used them quite a bit in caves! They get hammered
> in that instance because they don't have the water cooling & can get very
> hot.
> Other people have oil filled spot lights used on off road vehicles
> successfully, but I wanted more of a race car look to my sub & wanted to
> avoid the oil.
> If a housing or light came up that was suitable & easy to adapt I would
> use it.
> But bare in mind that most online lights would need marine anodizing.
> Alan
>
>
> On Wednesday, December 30, 2020, 08:08:07 AM GMT+13, Rick Patton via
> Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>
>
> I built my own aluminum exterior light housing, 6 each, using a cob led
> bulb that was 10,000 lumens, DC 34 volt and about 100 watts. My friend
> found them online and they were about $3.50 each.
>  I fried a number of them due to poor heat sink or driving them too much
> and finally got them dialed in. I asked my friend to buy some more and he
> said that the source in Japan does not sell them any more.
>  I found something similar here in the U.S after hours of searching that
> matched pretty closely to what I had but they were about $38 each. Is
> anyone using something similar as far as lumens goes that has any sources I
> could try or is that price about the best I can do?
>
> Rick
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