# Want to design a 10,000 lumen underwater light ( Runs off 12v boat battery )



## choppedliver

I need to design an underwater light that will put out a true 10,000 lumens. Or maybe a 5000 lumens and make two of them. 

I don't care about distance. Anything more than 30 feet of underwater illumination is irrelevant. I need wide angle.

Not brand new to the forum, but fairly inexperienced in the led world. Do have a rusty crusty electronics background.

My priorities:

1. LUMENSSSSSS
2. Efficiency
3. Price

I saw on another thread the XLamp CXa2011 can put out 4000 lumens???

I looked at the cree website, looks like it runs on about 40 volts. Was considering several 12v lawn mower batteries in series, or one car battery with some kind of voltage booster. 

How would YOU design this. It's going to be underwater, so it won't burn up , will be mounted to stainless steel most likely. But I also need enough heat sink it can be out of water for a few minutes without damaging it. Interested in choice of emitters, voltage regulation, etc

Thanks in advance
CL


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## jeowf

I too am inexperienced with the led world but I think you should try to get the light to lower it's output when it's take out of the water (measure the resistance across two external contacts i.e a water detector). Then you won't have to carry as much metal out of the water.


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## choppedliver

jeowf said:


> I too am inexperienced with the led world but I think you should try to get the light to lower it's output when it's take out of the water (measure the resistance across two external contacts i.e a water detector). Then you won't have to carry as much metal out of the water.



The weight of this device is fairly irrelevant.


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## ledguy

I've just worked on a smaller output project but the concern is same as yours here is my result:

For Lumens effeciency and Cost, it is one or the other, if you want to have maximum effeciency you will see to pay higher price. If cost is your primary concern then you may get the total output but at a higher wattage. Here is an example:

For 10,000 Lumens you can find a common 100 Lumens @ 1 Watt device, and you will need 100 of them, place them on any board and just make sure you have enough heat sink function for the unit and you are at 10,000 Lumens. 
Highest effeciency I can find it is CREE 1000 Lumens @ 10 Watts: http://ledsupply.com/creexml-w280.php , 10 pcs run you about $9.72/pc. so that is at $97.20

Lowest cost I can find is this 1 Watt LED : http://www.aopled.com/images/AOP_PDFs/L963/L963B-PLWC.pdf , 100 pcs last time I checked is at $0.65/pc. so $65.00 

Rest is whatever you want for size and shape and lensing.


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## xul

This
http://en.wikipedia.org/wiki/Sodium_vapor_lamp#Low_pressure_.2F_LPS_.2F_SOX
has 200 L/W but you may need some electronics.
50W @12v is about 4A.

Also, 50K hours at 3W for an LED can translate to much higher power for short periods and plus you've got water cooling. 
I've seen four different math models for LED aging, two linear and two exponential. Pick your aging model and figure your 
lumens vs. life 
tradeoff.
At really high current densities the interconnection metal actually migrates, if it doesn't melt outright.

BTW, SS is probably a lousy thermal conductor.


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## choppedliver

I know lots of people with low pressure sodium lights. I am explictly NOT interested in low pressure sodium lights.

The housing will be stainless steel for salt corrosion reasons. The stainless steel can have an aluminum plate for better thermal dissipation. But as was stated, it's designed to be used under water, so cooling is not really an issue.


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## choppedliver

ok... scratch that , the CXa2011 runs on 40v... and it just occurred to me that wouldn't be safe under water in case of malfunction. Apparently 40v is the threshold of might be safe/might not. So if I could stick to something in the 12v range, that would be great. My post hasn't garnered much attention, so if there is someone on here who would like to work with me offline/on phone/skype/whatever, I would be willing to compensate someone for their time.


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## xul

40v in an ungrounded light could be dangerous if you were grounded and the light failed by shorting to the case. Since the light is grounded in water I don't believe a person, grounded or not, would be in danger. But I'm also not risking my own life with this opinion. 

I'll have to run through several possible equivalent circuits to see if any of these place a person in danger. Above 20 mA through an adult male is dangerous.
This is not quite the same as getting a shock from swimming pool lights, which is a much more common occurrence.


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## videoman

How about using 2 enclosures, each having 6 Cree XM-L in the neutral tint variety ( my choice for UW use) , 3S2P configuration . a Taskled H6CC driver, 6- Ledil wide Booms ( check out their specs for angle, should be like 50 deg. in every direction). You can however, make a single enclosure of 12 leds and 2 drivers of course. the H6CC has the added benefit of a dimming pot. Make sure all connectors, plugs, jacks etc. are waterproof. This configuration should give you approximately 10K lumens @ 3 ft.


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## choppedliver

xul said:


> 40v in an ungrounded light could be dangerous if you were grounded and the light failed by shorting to the case. Since the light is grounded in water I don't believe a person, grounded or not, would be in danger. But I'm also not risking my own life with this opinion.
> 
> I'll have to run through several possible equivalent circuits to see if any of these place a person in danger. Above 20 mA through an adult male is dangerous.
> This is not quite the same as getting a shock from swimming pool lights, which is a much more common occurrence.



yeah, I think it's something I'll just avoid. Everything for boats is 12v, and probably for a reason. 12v can't penetrate the skin and therefore the current cant run THROUGH the body. Assuming no cuts/open wounds, etc


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## choppedliver

videoman said:


> How about using 2 enclosures, each having 6 Cree XM-L in the neutral tint variety ( my choice for UW use) , 3S2P configuration . a Taskled H6CC driver, 6- Ledil wide Booms ( check out their specs for angle, should be like 50 deg. in every direction). You can however, make a single enclosure of 12 leds and 2 drivers of course. the H6CC has the added benefit of a dimming pot. Make sure all connectors, plugs, jacks etc. are waterproof. This configuration should give you approximately 10K lumens @ 3 ft.



That sounds great. I would love to talk to you about this perhaps on chat or phone. I am a quick learner. I can absorb more from one 10 minute convo than days of surfing forums gleaning info indirectly. 

I am thinking of a three sided enclosure, the top three sides of an octagon with two emitters on each facet. I could do two of these enclosures for a total of 12 emitters, and they would be mounted on the boat on opposing sides. this should provide quite a bit of overlap. Ideally it runs on 12v since that is readily available and requires no voltage booster just a straight run from a deep cycle lead acid battery. Most have around 100+ah ratings at 12v, and only needs to run at most 6 hours, so current draw is not much of an issue to me

I would like something in the cool white range as my experience has shown this to be much more effective for my use than the wavelengths experienced with halogen and hps. I have seen leds in the 9000k range that really perform, but really something around 5000k or so would be fine. What color temp would you call neutral?


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## videoman

Perhaps if you can explain more in detail what exactly you need the lights for, then I can suggest a few possible configurations. Do you need the light for just a broad wide-field illumination or for photography/video use ? do you wish to illuminate the bottom sea floor from lights mounted on the boat or just the upper surrounding water area ? Neutral white is generally in the 3500 to 4500K range. Light intensity diminishes rapidly underwater especially in murky lakes and near shorelines. That 10000 lumens is probably good for 15 feet distances on a wide field config. 10K lumens is like a 500 watt light bulb,may seem a lot but underwater is a completely different story.If you narrow the beam, you will get farther throw. Also to take into consideration is if that battery starts the boat or you will have a dedicated battery just for the light(s).


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## choppedliver

PM sent. These batteries are meant to be drained and are separate from the boat starting battery. 15 feet is plenty this is about illumination of a wide area in a short distance rather than long throw or direction.


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## cmacclel

Is this going in salt or freshwater? PM me with your budget.

Mac


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## xul

Sewer workers use 24v or 28v lights. 
C. Dalziel did a lot of work on electric shock but I can't seem to get his book through interlibrary loan.


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## jk930

how about PU encapsulated LED strip? 12V DC suitable for boat battery. It's waterproof IP68, could used in sea water.
the top quality of SMD 5050 chip could achieve 18-21 lm/pc, using 60leds/m strip, one roll(5 metres) 300 pcs LEDs,total about 6,000 lm, 72 watts.


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## lucca brassi

two CSM-360 gives you 12.000lm @ 12V/12A


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## broadwayjoe

Do you have a link to a manufacturer?


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## BobBarker

You are completely correct. In this use, High voltage DC is not an issue (at almost any voltage you could achieve). The problem would be with AC. Other than color, it's another reason dive lights should NEVER use AC light sources (like LPS or HPS). It's also the reason faulty 120v pool lights are so hazardous.


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## BobBarker

everything boat is 12v for the same reason that everything car is 12v... It's the 12v SLAB. It doesn't really have anything to do with safety. There was a reason that Mr. Eddison wanted to use DC for home power. For the same voltage differential DC is far safer... On simplistic terms, it's like comparing 30v DC to 15v AC.


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## BobBarker

If I was doing this for myself...

I would use the Bridgelux BXRA-40E7500-J-00 (4000K, 80CRI ($63.83 from my favorite supplier)
8250 REAL (actual in sustained use) lumen at 3.2A 30.5 that equates to 84.5 lumen/watt During sustained use.

or the Bridgelux BXRA-50C9000-J-00 (5000K, 70CRI ($76.65)
9416 REAL (actual in sustained use) lumen at 3.2A 30.5 that equates to 96.5 lumen/watt During sustained use.

use one TASKLED Hyperbuck @ $40

Don't bother with any kind of reflector (if you are wanting to use it at 15' or less and you want it to cover a large area... you don't really need it.

This gives the simplicity of a single large LED/ single driver setup, that can be driven by something as simple as 3 small 12v SLABs or as exotic as a 11-12cell Li-ion setup... For a setup with 12 (panasonic ncr-18650a) li-ion cells, it would weigh 19oz and run for a little over an hour or so (I figure about an hour and 5 min) or 3 7.2AH 12 SLABs (at a weight of 14lbs and figure maybe 3-4lbs for the heatsink (can be fairly small) and everything else... As long as the enclosure is greater than a 7.82" cube ( 476.76 cubic inches) it will be buoyant (so you could have more space for battery as ballast)...

So
$77 for LED
$40 for driver
$81 for SLABs
$5-10 for heatsink big enough for water cooling the LED
$30? for enclosure...
$20 for switches and wiring

So about $258 for the whole thing (give or take $20-30 


But that's just me...

Oh, and run time on the SLAB setup is about 100min...


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## choppedliver

jk930 said:


> how about PU encapsulated LED strip? 12V DC suitable for boat battery. It's waterproof IP68, could used in sea water.
> the top quality of SMD 5050 chip could achieve 18-21 lm/pc, using 60leds/m strip, one roll(5 metres) 300 pcs LEDs,total about 6,000 lm, 72 watts.



What is "pu encapsulated"?


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## lucca brassi

Poly Urethane http://www.wisegeek.com/what-is-polyurethane.htm


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## demonic69

3 of these: http://www.led-tech.de/en/High-Powe...REE-XM-L-U2-on-round-PCB-LT-1791_120_117.html
and one of these http://www.lck-led.com/constant-current-circuit-driver-modes-5512v9asst90-p-863.html?cPath=37_135
If you could get the voltage to 15 you'd be in!
If not you could risk direct driving them with a 9w 1Ohm resistor in series


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## jspeybro

perhaps this one:
http://www.cutter.com.au/products.php?cat=Leds+on+40mm+Round+MCPCB
together with 2 taslked H6CC drivers or so you should be fine I think.


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## thenativediver

Do your lights have to be LED?

I bought a couple of underwater lights from "fishnlights". I got two for my dock and one for my boat for looking for lobster at night.

It is a 200w CFL with housing (I think), and it lights up a nice area. Fifteen feet is no problem... in clear water anyway. Runs off battery (think it uses an inverter, but I don't remember)

You can lower the light on a pole or with a weight. 


How will you keep your lights waterproof?


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## thenativediver

My docklites, by same company, are metal halides and are 36000 lumens each (they claim) with 400w halides.

These are super bright!

What are you useing the lights for?


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