Recommend me a Flashlight for Scuba modifications.

[victorzamora]

Hey guys, I'm a long-time lurker, first-time poster. I'm in Aerospace Engineering at Virginia Tech and have a pretty solid working knowledge of batteries and simple electronics.

I'm trying to modify a flashlight to suit my purposes in technical diving. I don't know if y'all have heard of a canister light (I'm assuming you have as I've seen a lot of them on this site). A canister light is a light where the batteries are stored in a canister and there is a cable attaching the battery canister to the lighthead, which is typically mounted on your hand. If you are very familiar with canister lights, you'll know that it's not uncommon for them to cost over $1000. I think that's a little crazy for a flashlight. Prime example right here. Now, there have been multiple custom canister lights designed out there. I'm trying to make mine as off-the-shelf as possible. A lot of lights involve squeezing a 5*Cree R2 1200lm lighthead into a maglite and modding the crap out of both to get them to fit. I plan on using a MAGLITE-S4D016 with a dive conversion kit. Now, the problem is I don't want to have to hit anything with a lathe to get it all to fit. The glass lens in the dive kit is 5.2mm thick (thicker than the original lens). I'm looking for a drop-in light putting out at least 900lm. I looked at the Terralux 1000lm TLE-310mEX. I don't really need multiple power settings as all I need is "high", or a switch as that will be elsewhere. Any recommendations??

Looking back at it, how would an SSC P7-C work? Kind of low lm output....but I'd sacrifice some of the 1200lm from the 5*Cree R2 for a direct drop-in.

 

[Gunner12]

You can also buy Maglite Heatsinks from the custom B/S/T forum and make your own LED mod. i'm not sure how easy they are to find, but a mult-emitter heatsink could be best for you. Say have 4 Cree XM-Ls and 4 optics or reflectors in the light, and run all of them at decent current. Even if you use the T5 bin and only run it at 700 mA, you'll still get 650+ lumen out the front (probably more, 1000 lumen at the emitter). If you use the U2 bin and drive them at 3 A each, then you'll get 3500+ lumen at the emitter, and conservatively 2500+ out the front (probably closer to 3000 depending on the reflector/optic). No lathes needed, but there is soldering and fitting but that stuff is easy. As for drivers, that'll depend on the battery voltage.

Also, what about other multi-emitter lights? The Skyray King, or similar multi-emitter lights could work. They'll have the LEDs and the appropriate drivers, so you'll just have to make sure the battery voltages are in range and that you can increase the water resistance enough. Kinda wish I made use of the machine shop more often when I was still in college (Biomedical Engineer, so I'm not sure how much work it would have been for me to get permission).

The Trustfire X100 could be a cool mod too. 7 XM-L emitters, and if well the driver is modified, you can drive the LEDs pretty well and get 4000-5000 lumen out the front according to some mods (assuming the heatsink can dissipate the heat enough). It is a big light though (75mm diameter).

:welcome: Enjoy school! (the classes can be pretty tough, as I'm sure you know)

 

[victorzamora]

You can also buy Maglite Heatsinks from the custom B/S/T forum and make your own LED mod. i'm not sure how easy they are to find, but a mult-emitter heatsink could be best for you. Say have 4 Cree XM-Ls and 4 optics or reflectors in the light, and run all of them at decent current. Even if you use the T5 bin and only run it at 700 mA, you'll still get 650+ lumen out the front (probably more, 1000 lumen at the emitter). If you use the U2 bin and drive them at 3 A each, then you'll get 3500+ lumen at the emitter, and conservatively 2500+ out the front (probably closer to 3000 depending on the reflector/optic).

So I'm obviously a lot less educated than I thought I was. I don't know what the B/S/T forum is. As far as making my own LED mod, do you mean taking a custom combination of reflectors, emitters, and drivers? I wouldn't be opposed to that. Is the reflector and the heatsink the same thing? Emitters look pretty sizeable, are there any size concerns when picking emitters to go in certain reflectors? Also, is this feasible at a cheaper cost than buying an assembly? DealXtreme has some "drop-in" lights for like $20, including the SSC-p7C.

No lathes needed, but there is soldering and fitting but that stuff is easy. As for drivers, that'll depend on the battery voltage.

Soldering/fitting I'm fine with.

Also, what about other multi-emitter lights? The Skyray King, or similar multi-emitter lights could work. They'll have the LEDs and the appropriate drivers, so you'll just have to make sure the battery voltages are in range and that you can increase the water resistance enough. Kinda wish I made use of the machine shop more often when I was still in college (Biomedical Engineer, so I'm not sure how much work it would have been for me to get permission).

As far as Maglite vs other lights, I'm not stuck on Maglites. However, there's a proven mod out there to rate them for scuba-depths involving a saw and JB Weld and some o-rings and glass (the kit I mentioned in my first post). The Skyray King has the disadvantage of using a button to turn on. Buttons, when subjected to water pressure, become ineffective even if they don't leak.

The Trustfire X100 could be a cool mod too. 7 XM-L emitters, and if well the driver is modified, you can drive the LEDs pretty well and get 4000-5000 lumen out the front according to some mods (assuming the heatsink can dissipate the heat enough). It is a big light though (75mm diameter).

That is a big light, probably bigger than what I'd want. Also, 5000lm seems like it could melt the walls of the caves I plan to be diving in.

:welcome: Enjoy school! (the classes can be pretty tough, as I'm sure you know)

Thanks. Classes are​ tough, but I'm enjoying school as much as I can.

 

[Gunner12]

B/S/T = Buy/Sell/trade. That forum is in the custom lights section.

It will be cheaper to buy a drop-in and fit it to a Maglite, but you can get more output from your own personal mod, unless you get/find a multi-XM-L drop-in. The Cree XM-L has a larger die size and can take more current and make more output then other smaller die emitters. It also means a more efficient emitter at the same current as othr emitters. The larger die does make a wider beam though. The XM-L has a similar die area to the Seoul P7, but on one die instead of spread across 4 dies. You can get the LED on a heatspreader, making mounting and soldering to the LED easier, but I'd be careful of driving the LED at high currents (> 2A) because the thermal conductivity through those start isn't great. The LEDs will be running hot at 2-3A and top out (output wise) at 3A on those heatspreaders.

The reflector and heatsink are two separate pieces, but one can screw into the other. Many different reflectors will work OK as long as the LED is at the focal point. There are also optics for the XM-L which also work fine, just make sure they were meant for the LED.

I was thinking that the button would be a problem for something like the Skyray King, but there are also similar 3 emitter lights with a tail clickie, where you can pass the power cord through. Some of them should also have a similar diameter to a Maglite, so some of the parts for the Maglite conversion should work too.

I've seen some Maglite divelights mods in the Custom Lights forum and they look pretty cool. How much output are you looking for? If it's under 1000 lumen, the drop-in would be the easiest path, just make sure that there is a good thermal path so the LEDs don't cook themselves.

5000 lumen is 20w of light, assuming Black Body Radiation (~250 lumen per watt for 100% efficiency).

 

[victorzamora]

B/S/T = Buy/Sell/trade. That forum is in the custom lights section.

Haha, thanks! I've never seen it referred to as B/S/T. I like that abbreviation, though.

It will be cheaper to buy a drop-in and fit it to a Maglite, but you can get more output from your own personal mod

Yeah, I figured. Isn't that always the tradeoff?

Unless you get/find a multi-XM-L drop-in. The Cree XM-L has a larger die size and can take more current and make more output then other smaller die emitters. It also means a more efficient emitter at the same current as other emitters. The larger die does make a wider beam though. The XM-L has a similar die area to the Seoul P7, but on one die instead of spread across 4 dies. You can get the LED on a heatspreader, making mounting and soldering to the LED easier, but I'd be careful of driving the LED at high currents (> 2A) because the thermal conductivity through those start isn't great. The LEDs will be running hot at 2-3A and top out (output wise) at 3A on those heatspreaders.

Multi- XML emitters are proving hard to find that will drop in to a Maglite.

The reflector and heatsink are two separate pieces, but one can screw into the other

Gotcha. Is the heatsink, then, the star-shaped piece I see on a lot of these LED's? Or is that just the board with the heatsink being a large piece of metal? As far as cooling goes, water is a FANTASTIC conductor...so even warm water will cool the light better than air. As long as I can transfer the heat to the case of the lighthead I'm not worried about temperatures.

Many different reflectors will work OK as long as the LED is at the focal point. There are also optics for the XM-L which also work fine, just make sure they were meant for the LED.

Cool, I'll have to keep that in mind.

I was thinking that the button would be a problem for something like the Skyray King, but there are also similar 3 emitter lights with a tail clickie, where you can pass the power cord through. Some of them should also have a similar diameter to a Maglite, so some of the parts for the Maglite conversion should work too.

It was a problem I hadn't really thought of until my investigations got more serious.

I've seen some Maglite divelights mods in the Custom Lights forum and they look pretty cool. How much output are you looking for? If it's under 1000 lumen, the drop-in would be the easiest path, just make sure that there is a good thermal path so the LEDs don't cook themselves.

I'm not completely sure how much output I want/need....but the two that I'm "competing" against are: number1 and number2. One of them says 750lm at full power, but that it reduces power as batteries wear down to increase battery life. The other says 1000lm. They also have 6000k and 5600k color. Not too concerned about the color, honestly, as long as it's in that close-to-white spectrum. I was originally looking at the 1200lm 5*Cree R2 setup. However, I'm not too concerned. The SSC-P7C at 900lm I'm sure will be plenty. I purchased commercially-produced backup lights and they're like 200lm. 900lm should be enough, but I wouldn't be opposed to a more powerful light. I'm looking for multi-diode reflectors as well as single massive diode solutions. However, with my (possibly flawed) logic...I'd like to think that multiple diodes would reduce the chance of total light failure, right? I mean, it would reduce one "catastrophic-failure" point.

5000 lumen is 20w of light, assuming Black Body Radiation (~250 lumen per watt for 100% efficiency).

What kind of efficiency do LED's, HID's, and Xenons get, though? I'm sure nowhere near 100%. Following your ratio of 250lm/W, my backup LED light is 3W and 210lm. "Should" be 750lm. Efficiency of about 28%. Right? As far as I'm aware, LED's are even better than HID's as far as efficiency (a 20W LED is brighter than a 20W HID).


As far as powering this bad boy goes, I'm still undecided. I figured I'd settle on a light and then take my other requirements to settle on the battery sizing to suit.

 

[Gunner12]

The star/round board is the MCPCB (metal core printed circuit board). It's much more of a heatspreader then a heatsink and it makes the LED easier to work with. The LED is the thing soldered to the middle of it. The XM-L by itself is 5mm x 5mm, with 3 pads on the bottom, +, -, and a thermal pad. The XR-E has a larger package but a smaller die (takes less current). The star itself is mounted on the heatsink, usually with thermal paste/glue, and sometimes a few screws.

Water is a great conductor, so as long as the thermal path from the LED to the outside is sound, the LEDs will run pretty comfortably.

The Seoul P7 is 900 lumen max at the emitter (at full drive current), so there is less output out the front. If you want to hit 1000 lumen out the front, you'll need more LEDs, or a single Luminous SST-90 (3mm x 3mm die, 2000+ lumen max, but makes a lot of heat). Besides output, what about a tight beam? A tighter beam will cut through floating particles easier then a flood/wide beam.

More LEDs might not mean more durability. If the LEDs are wired in series, then when one fries, they will all go out (very unlikely though). For most redundancy, each LED should be hooked up to it's own driver circuit.

Wikipedia has a decent page on luminous efficiency. Generally, a good HID and a good LED have similar efficiency, but the HID can be much more powerful and be focused. LEDs can be more efficient at lower currents, turn on (near) instantly, last longer, and can run at multiple different output levels. LEDs are also catching up to HIDs in terms of raw power.

Now, what light do you have. Is it actually 3w to the LED? Is 210 lumen from the emitter, out the front, or a calculated value? You can look at LED specifications from different companies and figure out the efficiency from there. For example, the Luxeon Rebel ES cool white ( ~6000K), is 200 lumen at 700 mA at a voltage of ~3v, so that's 2.1w to the LED, giving you 95.2 Lumen/watt. Or at 350 mA, it's 135 lumen and ~2.85v, giving 1w, so it's 135 lumen/watt.

At higher powers (and heat) LED's loos efficiency.

For tail clickie lights, you could remove the switch, and pass the power cord through the hole where the switch was, but then you'll have an empty body that might be buoyant. Cool be interesting trying to make a light that is neutrally buoyant.

Which year of engineering are you in? Also, I learned some TIG welding in one of my classes, did you get a chance to weld before?

 

[victorzamora]

This is like the third time I've typed this up...my computer is not happy about posting this for some reason.
Thanks for clearing up the MCPCB thing. That's what I thought, but i wasn't sure.

I think an SST90 would be overkill at 2000lm+, I really "need" 600lm, would prefer 900lm, and wouldn't mind getting 1200lm. I do need/want a tight beam, though. That's the only thing keeping me away from one of the Terralux 31M upgrades.

Good point about durability. As far as what light I have, I have no idea what the exact specs are. I just bought this light.

About buoyancy, a little lead will go a long way. I'm also planning on making some sort of heatsink to try to weight the lighthead down if the handle doesn't.

I'm a Senior Aerospace Engineering student, and I have not gotten a chance to try welding.

Now, is there a ~900lm drop in that would require 0 mods to the maglite? What would you specifically recommend as far as me "building" my own drop-in system for the maglite? If you can't post links, would you mind PM'ing me or e-mailing me?

 

[Gunner12]

I haven't modified a drop-in to fit a Maglite, but the one's I've read about (here and elsewhere) seems to require some trimming to fit. DX does have a 3 XM-L drop-in for $30 but it seems like it's a bit too big to fit, and heat could be an issue if the LEDs aren't secured correctly or heatsinked well. (you could always open it up to check)

Here are three threads of other custom divelights from Maglites:
http://www.candlepowerforums.com/vb...inium-canister-Maglite-mod-with-tree-SST50-5A
http://www.candlepowerforums.com/vb/showthread.php?279248-Maglite-mod
http://www.candlepowerforums.com/vb/showthread.php?203029-P7-Maglite-dive-light

Here's two threads of Maglites modded with the 5x XR-E module. No mods to the maglite, but you'll have to drim the drop-in a bit:
http://www.candlepowerforums.com/vb/showthread.php?344584-3D-Mag-with-5xR2-Module
http://www.candlepowerforums.com/vb/showthread.php?342060-Two-more-1200-Lumen-Mag-mods-%28Plenty-of-pics%29

There are also many other threads on other Maglite mods that you can tweak to get the water resistance you need. I don't have any specific recommendations.

A single well driven XM-L emitter (3A) should have the output you require (~600 lumen out the front) and makes a fairly narrow beam with the stock Maglite reflector. A mod like that would consist of the XM-L emitter (preferably on a good but small MCPCB), a Maglite heatsink, and a driver that can push 3A. H22A has the Maglite heatsinks.

Download has the Multisink if you want a multi emitter mod. Not sure if they are still for sale, just search up multisink in the search box above. You'll have to find either 4 drivers, or a driver that can push 4 LEDs in series (or two driver for 2 in series, etc.)

LEDs can be had from many different sources.

I've never had a chance to dive, but it looks like fun.

For the light you have, does it use a separate battery carrier? If so, you might be able to get more output and runtime by switching it to one Li-ion battery, something like the 18500 or 26500 might work, you'll have to check dimensions before you buy of course.