[PSUBS-MAILIST] Light lense

Wed Sep 2 17:54:33 EDT 2015

Alan,

Usually if the driver is a true current source the extra wire doesn’t make much difference (within reason).

Also most drivers filter the switching waveform so the current to the LED is mostly a dc tern with a very low AC component.

Take a look at the design we have on the forum tomorrow late to see what the present design is.

Ken

From: Personal_Submersibles [mailto:personal_submersibles-bounces at psubs.org] On Behalf Of Alan via Personal_Submersibles
Sent: Monday, August 31, 2015 8:49 PM
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org>
Subject: Re: [PSUBS-MAILIST] Light lense

Hank, that's a good question for Ken.

As I understand it, the LED drivers have a switching frequency so are turning on & off

the power to the LED. When electricity runs through wire it creates a magnetic field &

when the power is switched off, the magnetic field collapses & causes a surge of electricity.

Like a coil in a car creating a spark across a spark plug. The LED doesn't like this. 

The longer the run of wire, the more inductance is created. The capacitor is a buffer for this

& there are big ones on high power LED drivers. They are there to combat the inductance from 

the battery to the driver, but by lengthening the wiring from driver to LED you create the 

problem out the other side. Perhaps a capacitor could be placed in the light fitting, & the

driver in the pressure hull. This would reduce the footprint inside the fitting & stop the rest of the electronics from being exposed to any heat build up. you would still have the problem

of pressure on the capacitor if you compensated though. Have seen pressure resistant

capacitors, but don't know enough about them.

I will go & see a friend who is an expert on this.

Alan

Sent from my iPad

On 1/09/2015, at 11:20 am, hank pronk via Personal_Submersibles <personal_submersibles at psubs.org <mailto:personal_submersibles at psubs.org> > wrote:

Alan,v

Why can't the driver stay inside the submarine, why put it in the housing?

Hank

On Monday, August 31, 2015 4:55 PM, Alan James via Personal_Submersibles <personal_submersibles at psubs.org <mailto:personal_submersibles at psubs.org> > wrote:

Hank,

you have got me thinking. I don't want to pressure compensate because of the capacitors

in the driver. I was also concerned that any fluid might yellow with the heat.

According to this article, the main problem with LED lights is disipating the heat that comes

out the back of the emmitter.

http://www.deepsea.com/wp-content/uploads/article-Application-of-High-Power-LEDs-UI08.pdf

I could seal off the driver compartment at the back of the emmitter & fill that with oil. However

I will be machining this out of alluminium rod & can keep the enclosure round the driver pretty small

so there isn't much of an air gap to the housing.

Could easily experiment with & without oil to see if it makes much difference.

Alan

  _____  

From: hank pronk via Personal_Submersibles <personal_submersibles at psubs.org <mailto:personal_submersibles at psubs.org> >
To: Personal Submersibles General Discussion <personal_submersibles at psubs.org <mailto:personal_submersibles at psubs.org> > 
Sent: Tuesday, September 1, 2015 10:09 AM
Subject: Re: [PSUBS-MAILIST] Light lense

Alan,

I assume your going with a pressure housing?  why not fill the pressure housing 95% full of oil to tsf the heat to the water?

Hank

On Monday, August 31, 2015 4:00 PM, Alan via Personal_Submersibles <personal_submersibles at psubs.org <mailto:personal_submersibles at psubs.org> > wrote:

Sorry part 2 ( ipad & big fingers)

The LED cost $11- & the driver $6-.  Free delivery.

I have ordered a number of reflectors for a couple of dollars each.

The driver is quite small. With the automated assembly processes

& micro sized components, you can't get anywhere near this size

soldering on the components yourself.

Because of the heat factor I am limiting myself to the 6000lm LED.

Will be looking at the beam angle I get from these reflectors & available glass 

lenses, before making up a housing. Looking for a borosilicate lense

because of the heat transfer & low expansion.

I have taken a different route from Ken, but this process he started has

been very helpful & motivating, as has been the discussion & information

that has come out. 

Alan

Sent from my iPad

On 1/09/2015, at 9:42 am, Alan <alanlindsayjames at yahoo.com <mailto:alanlindsayjames at yahoo.com> > wrote:

I bought a 24-36V 6000 lm & 4000 lm LED array along with drivers, 

& have another lot in the post.

The driv

Sent from my iPad

On 1/09/2015, at 4:09 am, Cliff Redus via Personal_Submersibles <personal_submersibles at psubs.org <mailto:personal_submersibles at psubs.org> > wrote:

Ken is in Ireland on a holiday but before he left, he had finished the design of the LED Driver power stage.  Still working on the housing but have been sidetracked the last month on getting my boat ready to dive after major upgraded over the last 18 months. Hope to get back on the Light housing shortly.  I did dive the new 5K LED light this weekend and it worked great.

Cliff

On Mon, Aug 31, 2015 at 8:09 AM, Jon Wallace via Personal_Submersibles <personal_submersibles at psubs.org <mailto:personal_submersibles at psubs.org> > wrote:

What has happened with the light build?
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