Hi, This is my first post on the forum my name is Tibo.
My project is to build a powerful underwater light to install on the transom of my boat similar to the Bluefin Piranha P12.
I have been reading a lot about led on different forums which give me an idea where to start but I have still a lot of questions.
My plan is to CNC an housing from 6061T6 aluminium where will fit 4 set of triple green XP-E2 MCPCB. A10509 Carclo Lens (frosted wide) will be fitted on each of them.
The light will run for hours, what safe current should I aim for to drive them? The MCPCB will be in contact with the aluminium housing using thermal past, it will act as a water-cooled heat-sink.
I was thinking about tow option to drive them: (Input voltage will be between 12.4-14.5v depending if the outboard is running or not.)
Option1: Using one 1400mA (or 2100mA if possible) BuckBlock per triple star (will need 4 of them), the led on the star will be connected in series.
A009-D-V-1400 BuckBlock DC LED Driver
Option2: Using 2x boost up LDH-45A-1050W per light. Each of them driving 2 star in serie. The max current will only be 1050mA.
Is there other way to do it?
Which triple MCPCB (serie) would you recommend, they will be water-cooled, is it correct to assume heat shouldn’t be an issue?
Wide input voltage, you should probably use a buck/boost/buck-boost converter.
You could hit it with 2.1A per triple, limiting current to 0.7A per LED, making them nice and happy.
Still, each triple will mean that all 3 LEDs will be sharing the same board, dumping almost 8W of heat per board.
Make sure the shelf these boards will be mounted on will be thick, with blind threaded holes to mount them. Best if that’s also in full contact with the water (ie, deliver conditioned voltage to the LEDs, with the driver onboard the boat). Ie, the underwater light would be just the LEDs/lenses/case.
Sure I will post advancement. Thanks for the advise Lightbringer. 2.1A per triple to feed 0.7A per led would mean to connect them on parallel on the star right? The aluminium housing will be a solid round aluminium plate with 4 recess, one per star.
Bluefin claim 6200 fixture lumens for the Piranha P12 with 12 leds, this seems quite a lot…
Fixture Lumens 6200
Voltage 12V 4.6 Amps
Lens: optical grade high impact polymer,60 degree beam angle
Look at these as well. They are 12v and require no driver. They are Very bright. You can pot these in a clear epoxy on a heatsink and they work great underwater.
You could use Hyperboost and drive all LEDs in one serie. It goes up to 80V, you can set output current up to 3.2A (not with 80V output, but you will be somewhere around 1A anyway), for one mode just use on-board trimpod to set required current. http://www.taskled.com/hboost.shtml
www.cutter.com.au use to have them as well but I don’t see them now, they have only HBFlex, maybe you can call them if you don’t want to order from US
I guess you don’t need optics, right?
Also for color LEDs, check out luxeonstar website.
You can configure this board to serie or parallel (solder pads on it)
They are comparable to XP-E2 in output, good bin may be even better, Cree is not really into color LEDs I belive.
Thanks for suggesting the Hyperboost, it looks like a really good option. I will check with Cutter if they still can supply it.
For the led it seems light saber builder tend to rate higher the XP-E2 vs the Rebel, I will try to find some documented test. The XP-E2 on a tri star is quite a bit cheaper on Ledsupply.
I can send you older version of Hyperboost for free if you interested, you can check it out before you decide.
It is version 1.1, not much difference except it goes to “only” 2A output, but this should be plenty for you.
If you want PM me your address, I will try to get to post office (considering current situation).
Read technical info before using it Hyperboost Technical
Ops, you right about LEDs, didn’t notice price.
LEDSupply has them as well (tripple and not on SinkPad but normal MCPCB should be fine in your case, normal - no direct thermal connection of LED to metal)
Also from their data looks like XP-E2 is bit brighter, 107lm vs 100lm @ 350mA and still XP-E2 is cheaper ($10.49 vs $14.47 for tripple)
Check out Cutter
They have green XP-E2 tripple on 20mm Noctigon for 8.22USD and some other trippleas and quads below 10USD
Hi telephoneman, thanks for the link, I will get one to test out of curiosity.
Arek98 thanks a lot for the offer I sent you a PM. Looking more into the Luxeon Rebel I found out they have it in Lime , the wavelength would work for my project and it would actually look quite cool, different from what exist on the market. The Rebel in Lime is really really bright (167lm at 350mA) for a really low forward voltage 3v max. it should be really interesting to play with.
For the optic the Carlco wide has a 40deg beam, I think it is already too narrow for my application. Do you think a 2.5mm tempered glass lens would work?
For optics i think you good with bare LED.
I guess it will be used for catching shellfish so we talking light up to few meters underwater and bottom not much farther.
Needed thickness of lens depends also on diameter but again at few meters 2.5mm glass is plenty for any size that may apply here.
You may also consider using Polycarbonate AR (Abrasion-Resistant)
Something like this: https://www.tapplastics.com/product/plastics/cut_to_size_plastic/polycarbonate_sheets_ar/517
Here the have 3, 4.5, 6mm thick.
It will scratch easier than glass but you really have to hit it to make an impact, certainly it will not crack on accidental bump into a stone.
You said about machining so certainly cutting circle out of it will be no problem and you can buy even small piece.
You will need cable and gland I believe.
For glands I used plastic ones in the past and they are good (for diving light that was at about 30m underwater)
And they are cheap, have strain relief, note that orings need to be ordered separately they don’t come with gland.
Also for a driver I just realized that HBFlex will work for you as well. It is also boost driver and goes to 48V output, but it has UI which in your case is unnecessary.
The light will be 40cm underwater on the boat transom, cable gland will work yes. Are you afraid 2.5mm tempered glass will break to easy?
I started on the CAD. The tempered glass would be glued on with a PU sealant. I don’t plan to make the housing in 2 parts with screws to open, if I have to open it, I would have to increase the whole thickness. Worst case I can break the lens and scrap the PU sealant and reseal if I have to open it.
Is it enough to secure the stars with 2 screws each?
Yes, is enough to secure star with 2 screws, use thermal compound or pad, don’t use epoxy, it may crack over time and heat transfer will suffer (general, some epoxy may be good but to much hassle finding if and then how to get it)
I would make this one piece, everything goes in thru the front.
I would not use any sealant, just o-ring, static axial seal, pressure will only help.
And then fasten lens with screws, can be done with both polycarbonate (easy) or glass (need to drill holes before tempering, and probably some cushioning washer), but I would be a little uneasy with using this with glass.
So, you need 2 pieces, but still you can screw lens to front piece and then use o-ring between pieces and also screw them together (maybe the same screws just long enough).
Avoiding threads - extra machining and problem with twisting wires
Is there a big difference of performance for a flat lens between tempered glass and perspex. Also how does the thickness of the lens impact performances?
