Planification before the project...

[bobmirko]

Hi guys,

I plan to built my own canister light. I looked for a 3 emiter with a bean of like 8-10 degrees. I planed to pack it with 3 R2 or 3 P7 but my concern is about the "strenght" of the beam... I explain... I dive in cold water with lot of dirt in suspension so Im affraid that a more powerful light will be problematic in this kind of environment. I need a navigation light the most efficient in term of power/strenght for 6-30 feet visibility water...

Since design and field use is not the always the same I ask to the pro's!

What do you think it will be the best for the design? 3 x R2 with 1 amp of current or 3 P7 at 350mA or something like that? Do you think the Der Witchtel beam will be good for what I need?

Bigger is not always better... so if you can I will appreciate your help!

Thanks a lot!

P.S: Please forgive my bad english...:crazy:

 

[MrNaz]

What do you think it will be the best for the design? 3 x P2 with 1 amp of current or 3 P7 at 350mA or something like that? Do you think the Der Witchtel beam will be good for what I need?

Bigger is not always better... so if you can I will appreciate your help!

Thanks a lot!

P.S: Please forgive my bad english...:crazy:

Hi there! Your English is fine :cool:

I would recommend the 3x R2 setup, as R2 LEDs can be focussed into a far tighter beam that will not cause as much backscatter from the dirt suspended in the water. The tightest beam that you can get is from an aspheric lens, but they are very hard to use. I have just finished building my dive lite, and I have a nice beam about 12 degrees with little spill, which should be OK. I have used optics that are designed for the Cree R2 and fit on it perfectly, you can get them here:
http://www.dealextreme.com/details.dx/sku.1920

I use these on R2 LEDs you can see here:
http://www.dealextreme.com/details.dx/sku.15943

This combination is very good, the light colour is very white, with a very smooth colour. All the parts fit together easily. You can see some photos from my dive light build here:
http://www.mrnaz.com/?s=publish-gallery&album=57

I hope this helps! Good luck :twothumbs

 

[Linger]

a bean of like 8-10 degrees.

Aspheric lenses sound like what you are looking for. You don't want any spill to backscatter and cloud your vision, right?

Read up on Packhorses' builds
read down a few posts when the aspheric first goes in. From there it gets good.
http://www.candlepowerforums.com/vb/showthread.php?t=204107

again, look for the aspheric lens (with the square beam)
http://www.candlepowerforums.com/vb/showthread.php?t=228494

The aspheric lens takes a Q5 or R2 and focuses the die (thus the square beam) and projects it like a laser underwater.
Best,
Linger

 

[bobmirko]

That good advices!

Before your recommandations I thinked to use this with the R2:

http://www.dealextreme.com/details.dx/sku.11921

It's pretty close to the Sartek 6600 I think... this light do a pretty good job in our conditions of water and I planned to wire it with a Wired BuckPuck 1Amp with a pot to be able to drop the power if needed when I dive dirty water.

It is a good idea or no?

 

[bobmirko]

Here is the video of the Sartek beam...

http://www.youtube.com/watch?v=uJbU-qb0ixA&feature=channel_page

 

[Linger]

IMHO, that reflector isn't as good as aspheric could be. Simply because it still has some spill.

 

[bobmirko]

I like the idea of the aspheric lens... Correct me if I am wrong, this build will take the same 3 R2 led emiter but I have to put only a new lens instead of the reflector right?

Where can I get a good lens for a reasonable price that will handle the depth?

 

[bobmirko]

What kind of heat sink do I will need for a MC-E (WG) or P7 3 led set-up? How much power do I really have to dissipate? I plan to built a plastic casing and put a cutted old PS heatsink cutted to 50mm...

I plan to drive it at 1A for the 3 LED's in series

What will you take for heatsink?




P.S: that the project #2, the project 1 with 3 x R2 with aspheric is already started!

 

[wquiles]

If you are driving the MC-E/P7's at spec (2.8Amps or so each), you will be dissipating about 10 watts each.

The heatsink/platform for your LED's has to basically be large enough to house the LED's and whatever reflector/optics you will use. Since the light would be by definition water-cooled, as long as the heatsink can transfer the heat to the outside of the body (and therefore the water), the size/shape is not critical. If you are using one or more LED drivers, those might need to be heatsinked as well.

 

[bobmirko]

In order to minimise heat dissipation I will drive the LED in serie at 1Amp, so it will deliver around 500 lumens each

The casing will be in plastic and since it will be sealed I need to know what size of heat sink will be ok for the job

 

[wquiles]

The casing will be in plastic and since it will be sealed I need to know what size of heat sink will be ok for the job

No isolated heatsink will be OK. The heatsink's job is to transfer energy away from the source. If the heatsink is encased in plastic and will therefore have a poor thermal path to the outside, the size of the heatsink is irrelevant

Even at lower power, with no thermal path to the outside, you will not get an optimal solution since the output of the LED's drops as they warm up. Even if you make the heatsink HUGE, it does not mater since there is no thermal path for the heat to escape outside of the flashlight. The LED's could eventually overheat or be permanently damaged, and your driver(s) could also be damaged by the heat.

Basically an isolated heatsink does nothing, and it is not a good design idea for a flashlight with LED's. I strongly advice you to find a way to get good thermal transfer between the heatsink and the outside (cooler) environment.

Even when there is thermal transfer possible, note that there is no perfect size for a heatsink. It is all related to the thermal load, what temperatures you can live with in your particular project, and the ambient temperature. This recent thread has all of the math to give you an idea of what is involved:
http://www.candlepowerforums.com/vb/showthread.php?t=240896

Will

 

[bobmirko]

I will do a metal casing, no choice!

Thanks for the advice about that, I will take a maglite 2D casing. Do you have any special recomendation for this kind of casing?

 

[Linger]

bobmirko,
The M*glight D head is a popular light head for canister dive lights. I haven't done it myself but it is a common intro DIY. Good choice.

There are how-to guides. keep looking.

 

[bobmirko]

the only problem I can see with a Mag casing is the switch... Do you keep it working or you put epoxy/silicone to seal it?

Also, does the Mag casing can go to 150 feets depth?

 

[Packhorse]

There is no way the stock mag switch is going to work at any reasonable depth regardless of how much cfrap you put around it.
As for the case working to 150 feet. Who knows? I dont! feet is like so last century for measuring depth. I'd use one bellow 150meters though. Not sure if thats more or less than 150feet. ;)

 

[bobmirko]

That a lot of depth, so around 200 PSI of pressure

What type of lens do you use?

 

[DM51]

Clicky switches are not good solutions for dive-lights. The pressure sufficient to activate the switch has to be reasonable, and a reasonable press required to activate it at 40 meters would be unreasonably stiff to operate at say 10 meters or out of the water. There are solutions to this, but they aren't perfect.

The best possible switch is the magnetic reed (Hall Effect) switch, which leaves the light body intact, without any hole requiring a seal.

 

[Packhorse]

That a lot of depth, so around 200 PSI of pressure

What type of lens do you use?

Sorry, I have never dived to 150 meters. Deepest I have had my Mag based light with a 3mm acrylic lens is 57 meters.

150 meters I would go for a much thicker lens. Maybe 6 -10 mm.

I am sure the rest of the Maglite would be good way beyond those depths.

 

[bobmirko]

I agree with you, the MagLite casing seem to be a good option for dive light. I need ont to handle 150' only

 

[bobmirko]

Does some of you ever saw the new BackUp light from Oxyckeq 3W, the Sartek 6600 BackUp and the Sartek 5W?

That incredible how powerfull these light are! What LED's and wiring pattern does these lights use?