Organizing my first DIY Dive Light

I am wanting to make a canister light. Battery pack on the BCD / tank and a remote hand mounted torch.

I think I want to use one of those universal delrin battery housings that I've found on this board. I want an on / off toggle switch on it.

I've been doing research on my LED's, and I've decided on the LED Engin LZC 4000K 700mA 42v 1850 Lm.

I'm stuck on finding a driver for it, however. Would yall be willing to help?

I'm going to be using a 15* lens with this. I'm going to lathe out some 2.75 Al bar stock to make the housing, mount the LED to a copper slug and tight tolerance the slug to the housing for thermal transfer. do some funky wavey pattern on the outside of the housing for increased surface area and aesthetics.

I want to mount a PCB on the inside behind the slug to hold the driver / circuitry.

Here's the tough part. This LED has contacts to light different "rows" of LED's, which could be used as a 1/2 on dimmer. How do I make a water tight switch on the hand torch to select off / 1/2 / full? Or howabout 1/2 being selectable, and full on with a submersion detector, so that you can't burn out the LED by turning it full on in air?

I'm going to be modeling this all up in Pro/e before I do any actual production, so I'll be posting screenshots as I go.

Thanks in advance. Let me know if I need to clarify anything.

Why that LED engine? Can you post pic? It seems like that is not really a good diving solution... At 42 volts, there must be about 10 LEDs on that module, right? Why a toggle switch? Nothing too bad with it but there are better options like piezo and magnetic switches...

The Taskled Flex drivers have built in programming capabilities for heat as well as accidental turn on and off. LED I would go with the Cree XML or a module containing 3 of them.

Why that LED? And why 4000K Are you making a video light?

I see this is your first post. Welcome to the forum!
I hope you'll find it as enjoyable and engaging as I have.

I suspect you'll find it's better to connect all the rows straight to the driver, and use the driver to control the brightness. That might depend on the driver, but LEDs want to be driven at constant current, so most LED drivers are set up to output a constant current. If you turn off half the rows, the driver will want to keep the total current the same, so the current will double in the rows that are left connected, not only defeating your purpose but also stressing or destroying the LED. The one exception to this is if you run two separate drivers, and turn them on and off separately. But then you are still controlling the brightness through the driver(s).

The driver you really want is either the Hyperboost or HBFlex from taskled.com. Not cheap but excellent. There may be (much) cheaper ones at dealextreme or kaidomain, but they aren't made in the US by a CPF member who you can contact directly for help. Don't get me wrong, the cheap drivers can be fine, as at least one prominent divelight modder will atest, and if you are making a bunch of lights, 25-35 bucks a pop adds up. But if you are making 1 or 2, for my money it's not worth screwing around with anything but the best.

To change output on the Hyperboost, you can attach an external resistor. Connect it through a reed switch, and you can use a magnet to switch between low and high modes. The magnet can be in some kind of ring or slider on the outside of the light, so no worries about waterproofing it. In case you don't know, a reed switch is a small glass tube with a magnetically operated switch inside. Bring the magnet close, and the switch closes. Sometimes they are encased in a plastic overmold for durability or other reasons. You could get creative with more than one reed switch and/or magnet to use a single ring to provide off/low/high functionality.

The HBFlex is more complex. It incorporates several brightness levels and even strobes under control of the driver. It requires only a single 'momentary' switch. You use various combinations of 'clicks' and 'presses' to program and operate it. Momentary means it only contacts as long as you hold it. Clicks are short and presses are longer. People have been using various methods to enable this in dive lights, but it looks to me like the 'prolonged piezo' switch is emerging as the favorite. You can search on 'prolonged piezo' and you will find several threads discussing it.

With the kind of power level you're talking about, you probably want less than half power for use in air. Depends on the size of the head. My first dive light is about 1.8" diameter and 6.5" long, and at 16W gets to about the maximum temp I'd want it to when operating in air (uncomfortable to hold, but not going to burn you quickly, around 65C, though I've never measured it). Your head is probably considerably smaller in surface area, thus will handle proportionately less power.

My light at full power is about 0.44 watts per square inch. If your head is, say, 15 square inches of surface area, and you want to hold it without discomfort, shoot for around 0.35 W/in^2 * 15 in^2 = 5.25W. If you really want to push it, and go for 0.5W/in^2, and you have 18 in^2 of surface, shoot for 0.5*18=9 watts. If you are only going to run it very briefly in air, the thermal mass of the head can absorb the heat for a little while and you can run it at full power. If you're interested, we can talk about thermal cutouts, protection, etc.

You could use HBFlex or Hyperboost but this LED has pretty bad efficency. 47V+ (they say 47V is at 700mA for LZC-00NW00) and 3000 emitter lumens (best case @ 1A, so you are looking at less than 60 lumens / W.

If you want this optic than maybe SST-90 will work with it. Would give you pretty much the same lumens at 30W instead or 45W.

Why 15 degree optic? For video/photo to narrow, for primary light to wide (IMO)?

arek98 said:

You could use HBFlex or Hyperboost but this LED has pretty bad efficency. 47V+ (they say 47V is at 700mA for LZC-00NW00) and 3000 emitter lumens (best case @ 1A, so you are looking at less than 60 lumens / W.

If you want this optic than maybe SST-90 will work with it. Would give you pretty much the same lumens at 30W instead or 45W.

Why 15 degree optic? For video/photo to narrow, for primary light to wide (IMO)?

Click to expand...

I'm trying to make a more "cave diving" oriented light. Is 15 degrees to wide?

I only stuck with the LED I picked because I needed to stick with one to settle my brain on, and start planning a design.

As far as heat removal goes, I can CNC mill / lathe the LED housing to increase surface area if need be with some fins. I do not plan to have a smooth cylinder to house the LED. As such, I'm not particularly worried about heat dissipation at this point as I am with finding an LED / lens combo that will give me max lumens and a lens that isn't too wide in diameter. I would like to keep the hand held / mounted portion of this light under ~2"-2.5" in diameter if possible. I want to wrist mount the torch.

I'm still relatively early in my design, so if yall have better recomendations for my optics / lens, I am open to suggestions. But I would like to have more than 2000 lumens (preferably around 4750K) and 8-10 hrs of battery life at full power.

I chose 4000K because it's more of a warm / neutral white. I don't like cool white underwater as there is enough blue down there already. I'm okay with 5000k, but would prefer to keep it more on the warm side.

DIWdiver, thank you for the welcome, and the lengthy informative post. I appreciate all the information!

Thank you guys.

I hear you as far as brain boiling from overload :laughing:

8-10h runtime is pretty long. I would start from battery in that case. What is a maximum size you are comfortable with? For 2000+ lumens OTF you need to count at least 40Wh battery capacity (taking into account lumens loss thru lens and optic/reflector, driver efficiency and fact that battery rating is usually at 0.2C). For 10h you need 400Wh, this is pretty huge battery. Building it with 18650 cells is probably not practical (you would need about 40 of them). This leaves you with Li-Po high capacity cells, like 10Ah ones and you will still need about 10 of them (configuration depends on LED used).

Once you settle on the battery capacity you will have number of cells you need. Next you should move to the LED, that will determine cell configuration in pack (required voltage from pack) and driver to power LED.

As far as lens you choose I don't like the fact that if you don't like the beam you pretty much stuck with it anyway. It has uncommon size of 61mm in diameter. Even if you want tighter one made by LedEngin it is bigger and will not fit (84mm diameter).

About 15 degree angle I'm not sure how it works for cave diving, it may be ok if water is clear. I never did cave diving. Recently I took couple of light to quarry for testing. With murky water and stuff floating in it tighter beam is better, I think that 10 degree is probably upper limit for me.

If you read diving sub forum here (more head spinning) you will see that lot of guys is using aspheric to get tightest beam.

If you really want something around 15 degree than maybe look into triple XM-L with Ledil Cute-3 optics (it is more than 15, about 19 if I recall correctly) or 7 XP-G2 or XP-E2 with matching optics, there is couple of recent threads touching this topic. With 7-up you should easily get 2000 lumens and around 15 degree beam. Head will be smaller (you can fit it in 40mm) and optics are available for different beam widths.

I have some lights with 3 XP-E and Ledil Cute-3 optic, recently I also test-build light with 7 Luxeon Rebels and matching 12 degree optic (I think is more).
Cute-3 fits in 35mm circle (LED board and optic), you can use 3 XM-L board in the same place with the same optic – you will get much more light but wider angle. 7 Rebels with optic fits in 39mm circle, the same will be true I believe for 7-ups sold by Cutter and Led-tech.

I will try to take some comparison photos tonight if you interested.

I would prefer to have a single optic providing the lumens I desire, if at all possible. I think I will revise my desire for a 15 degree lens, and will opt for a 8-10 degree instead as suggested. Still, need to find a bulb / lens / driver combination that will package in my wrist mount, and provide the lumens I require.

As far as battery power goes, I was considering making a pack of CR123's (1500 mAh) in a delrin canister attached via wire lead and mounted to the tank / BC.

There are some 18650 cells which have 3.2 Ah available as well.

Boosted98gsx said:

I would prefer to have a single optic providing the lumens I desire, if at all possible. I think I will revise my desire for a 15 degree lens, and will opt for a 8-10 degree instead as suggested. Still, need to find a bulb / lens / driver combination that will package in my wrist mount, and provide the lumens I require.

As far as battery power goes, I was considering making a pack of CR123's (1500 mAh) in a delrin canister attached via wire lead and mounted to the tank / BC.

There are some 18650 cells which have 3.2 Ah available as well.

Click to expand...

The 3.2 ahcells are for low current application. So, you need to consider the draw. Otherwise that 3.2ah will be more like 2ah... I have found that 2.6ah Sanyos will discharge at 2C or 5amps and lose no capacity.

Well then options I would consider are:

• Stick with your original idea (LedEngin LED and optic) and see how you like it (you have ability to machine parts yourself, for me having reusable housing is more important, for you it may not be a case).
• SST-90 with Fraen FML-N1-R – it would be my first choice if I could get my hands on that optics (8 degree TIR designed for SSL-90 and SSM-80). If you get it somewhere I'm interested in few pieces with holders.
• SST-90 with aspheric – personaly I don't like aspheric but they are used by many people and they like it (poor efficiency because lot of light does not make it to the lens)
• XM-L with Ledil Iris – easy to get, small (38mm diameter) cheap, tight beam (about 9 degree) but only one XM-L, so less than 1000 lm OTF
• Triple XP-G2 - I know you said you prefer single LED but I still think this is worth considering if you want more than 1000 lm and not very tight beam (about 15 degree) – also inexpensive, smallest of all at 35mm diameter and shallow depth. I find it also easier to assemble since optics hast 3 legs that go exactly into 3 holes in PCB. With single LED and optic with holder it is harder to center it (and TIR is VERY sensitive to position relative to LED).
• HID - started looking at this myself recently. Don't really like it but when going tight beam and high lumens this may be the only option sometimes.

As for battery even if you use Panasonic 3400mA, I would still not count it as more than 10Wh per cell at 2-3A discharge current. 2600mA Sanyo 350xfire mentioned is also about 10Wh even if it holds better at higher current.

For battery pack; remember that you can have many, many cells in pack but then monitoring them becomes a significant problem. One bad battery in whole pack may cause problems. You need electronics to monitor discharge and charge. Also something to balance batteries, either build-in in pack or thru hobby charger. Sometimes you need many cells to get required capacity but I would keep number of cells as low as possible (myself I wouldn't go above 20 cells in pack for sure).
You may consider going NiMh or even sealed lead acid. They will be bigger for given capacity but safer (each has its own problems though).

Okay, I'm thinking I've settled on my Optics setup. Let me know what you think

http://www.mouser.com/Search/Produc...CW00virtualkey62410000virtualkey897-LZC70CW00

with

http://www.mouser.com/Search/Produc...08-Hvirtualkey62410000virtualkey897-LLNS3T08H

and

http://taskled.com/hboost.html

Thoughts?

Here's some CAD that I've come up with so far.

These lenses are just way too big.

I agree that lens is really big. I don't know where the 45W number came from, I calculate 42V at 700 mA is 29.4W

If I wanted 2000 lm otf with tight beam, I'd look at triple XML with ahorton aspheric, which is 27mm. In a much smaller package you'll get much more light for the same power.

I've build two lights. The first was six rebels with matching lenses from Polymer Optics, and about 1000 lm at the emitters. The second is a single XML with ahorton aspheric, also about 1000 lm at the emitter. The second one is smaller, has a vastly better beam, and easily twice the light output. As far as efficiency, this particular aspheric I think is probably much better than most. For the tightest beam, the lens is only a few mm from the emitter, so it catches most of the light. Others I've seen focus much further away and so loose a lot of the light.

As far as batteries, the 3.2Ah ones might be okay at the fairly low C/8 discharge rate you are talking about. But for that size pack I'd think about going to batteryspace and using their 10 or 16 Ah LiFePO4 cells or their 10 or 21 Ah LiPo cells. That way you only have to deal with 6-12 cells. You'd need 72 of the CR123s - that's hardly practical.

In water, the fins are absolutely unnecessary for heat dissipation. They would be decorative only.

Wouldn't having three XML's under the same lens cause a funky scattered light pattern?

Also, the fins would help. How much is a different matter

DIWdiver said:

I don't know where the 45W number came from, I calculate 42V at 700 mA is 29.4W

Click to expand...

I assumed (my bad) he will be running this LED at least at 1A. Vf is little higher at 1A as well, this is where I got 45W. Emitter is rated up to 1.2A, so 1A is still below spec max.

Boosted98gsx said:

Wouldn't having three XML's under the same lens cause a funky scattered light pattern?

Click to expand...

I think DIWdiver is saying to use 3 XM-L, each with its own Ahorton aspheric. They are 27mm, so three will fit 58.2mm circle. Maybe little more because you may need some kind of holders for them.

Yes, three lenses.

And I didn't read the datasheet (my bad), just the quick specs on the Mouser page. You'd have to run it over 700 mA to get 2000 lm otf.

I have built a couple of 3 x XML and 3 x Ahorton aspheric lights for use on Coastguard SAR boats.
Puts out shed loads of light. Would make a great dive light.

Does anyone have any pictures that I can reference showing a triple XM-L light and its beam?

Find a pic of a XML and it will be the same (just 3 times as bright which is hard to judge on photos anyway due to exposure levels), that is assuming the use of the same optics and that they are aligned.

While this page does not show XML's it does show a triple SST-50 with 44mm aspherics vs 6x XR-E and ahorton aspherics vs SST-90 and 44mm aspheric.

The triple XML with Ahorton aspherics is very similar to the triple SST-50 with 44mm aspherics.

I should have some pics up on that build in the next few days.
I also have a triple XML using a DX50mm triple reflector. That puts out even more light than the aspheric build due to optical efficiencies but the aspheric light beam is a lot tighter and a lot more intense than the wide beam you get with the reflector.
I will try and get a comparative shot.