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View Full Version : DIY High Power Underwater LED Transom Lights (50w / 4500-5000 Lumen) For $25



ryangler
14-03-2016, 10:52 PM
Hi Guys,

Im looking to fit some underwater transom lights and am surprised by how expensive they are considering how cheap LED tech is these days, So...

I have an idea bouncing around my head to DIY my own using a simple LED circuit and some casting resin. The simple circuit would involve the below

Driver & 12v to 36v Power converter
http://www.ebay.com.au/itm/Constant-Current-DC12V-24V-LED-Driver-to-DC30-38V-900mA-10W-High-Power-LED-U35-/171951217137?var=&hash=item28091759f1:m:mYZyGHEmsG06lDuJQUgLwLA

50w LED
http://www.ebay.com.au/itm/10W-30W-50W-100W-High-Power-LED-SMD-Lamp-Chip-Bulb-Cool-Warm-White-Flood-Light-/221475182233?var=&hash=item3390f31699:m:m7Cu6dQhfeZ7UrZbwkqvD1g

Other materials
Casting Resin
http://www.ebay.com.au/itm/POLYESTER-Clear-Casting-Resin-1kg-Catalyst-/161985193256?hash=item25b711e528:g:TZAAAOSwqu9VA9Q Q


- Cut off some 100mm storm water pipe to use as a mould
- Mount the circuit board and & two small stainless bolts then the LED chip over the cop and will with casting resin, with the two bolts and cable coming out the back (see attached)
- Drill 3 holes in transom Sika the whole back of the puck and use the bolts to tighten it down and hold it in place till the Sika cures

Total costs would be
$8.60 Driver & Power Converter
$2.70 50w LED
$10.00 Casting Resin
$3.70 bolts and pipe offcut

$25 Total

So for $25 you have a 4500-5000 Lumen transom light the is a tad brighter then the top of the line $700 4000 Lumin Lumitec Seablaze X

Whats everyone's thoughts on this?anybody seen anything done like this before?

Dignity
15-03-2016, 08:13 AM
Hi Guys,

Im looking to fit some underwater transom lights and am surprised by how expensive they are considering how cheap LED tech is these days, So...

I have an idea bouncing around my head to DIY my own using a simple LED circuit and some casting resin. The simple circuit would involve the below

Driver & 12v to 36v Power converter
http://www.ebay.com.au/itm/Constant-Current-DC12V-24V-LED-Driver-to-DC30-38V-900mA-10W-High-Power-LED-U35-/171951217137?var=&hash=item28091759f1:m:mYZyGHEmsG06lDuJQUgLwLA

50w LED
http://www.ebay.com.au/itm/10W-30W-50W-100W-High-Power-LED-SMD-Lamp-Chip-Bulb-Cool-Warm-White-Flood-Light-/221475182233?var=&hash=item3390f31699:m:m7Cu6dQhfeZ7UrZbwkqvD1g

Other materials
Casting Resin
http://www.ebay.com.au/itm/POLYESTER-Clear-Casting-Resin-1kg-Catalyst-/161985193256?hash=item25b711e528:g:TZAAAOSwqu9VA9Q Q


- Cut off some 100mm storm water pipe to use as a mould
- Mount the circuit board and & two small stainless bolts then the LED chip over the cop and will with casting resin, with the two bolts and cable coming out the back (see attached)
- Drill 3 holes in transom Sika the whole back of the puck and use the bolts to tighten it down and hold it in place till the Sika cures

Total costs would be
$8.60 Driver & Power Converter
$2.70 50w LED
$10.00 Casting Resin
$3.70 bolts and pipe offcut

$25 Total

So for $25 you have a 4500-5000 Lumen transom light the is a tad brighter then the top of the line $700 4000 Lumin Lumitec Seablaze X

Whats everyone's thoughts on this?anybody seen anything done like this before?

Is this a mock up as I don't see any locating bolts, I know nothing of circuitry and therefore don't see why it won't work but others will let you know. You will need to add $20 for a tube of Sika and I also like to add an O ring to the bolts before connecting, maybe a needless precaution but none of my through hole fixings have ever leaked. The only other thing I've noticed on specs for some trailer lights is they mention a number of layers of resin, no idea why, once again those in the know might be able to advise.

Dignity
15-03-2016, 08:25 AM
Ryangler, I think think I have spotted the bolts, fairly small from what I can see and I just realized why there might be additional layers of resin, when you tighten the bolts if the initial layer cracks the integrity of the circuits etc won't be breached. I guess you will have use for the rest of the resin as the link you posted has it at about $23 +$15 postage.

ryangler
15-03-2016, 10:04 AM
Dignity, that's just a picture I found when I googled "LED casting resin" and is pretty much what I had in mind just with a few bolts cast into the back of it and the wire in the centre.

I think I would
- use a hole saw to cut out a 2mm thick disk of ali, drill a further 2 - 4 holes (in addition to pilot hole) in it for the bolts. This would spread the load across the back of the light and give you something to mount the circuit board to.
- pull the power cable through the pilot hole for the hole saw and cast this in resin first, making sure to leave the output wires of the circuit exposed, could even use a coloured resin for this bit.
- mount the LED chip to the outside face of the puck and solder on the exposed output wires
- cast the whole thing in a clear resin to seal it up

I figured 1kg of resin was 10cm3 so was thinking of making 4

I know bugger all about resistors and circuits too and up to yesterday the only thing I knew about LED's was that is stood for Light Emitting Diode and that they draw low current but run hot requiring heatsinks (not a problem underwater). After googling a little it seems you need a driver to run them to maintain a consistent current, the easy way around it is to purchase the ready made boards that in this instance will step up 12v to 36v and maintain a consistent 1500ma to run that particular LED chip.

shaungonemad
15-03-2016, 10:48 AM
My brother in-law just got a roll of led strip and glued it to the transom

Rip it up
16-03-2016, 02:55 AM
Ryangler. Polyester Casting resin also gets very hot when curing. So watch the batch size.

Any 12v led can be used. Think truck lights or trailer lights.

I have some 65mm round Led's on my ute tray. These would be perfect for a casting to seal them better. Single M6 bolt in the middle. Might need to extend the bolts though.




Damo's dodgy boat building repair centre.

deckie
16-03-2016, 10:12 AM
Luv it.
Couple of concerns i've got relate to the output over time.
It worries me the casting resin will yellow/discolour rather rapidly. Not only that but the face will scratch very easily and greatly reduce the output.
Is there some sort of glass or scratch resistant clear face you can use ?
The heat will be huge and hence as a DIY project it might be prudent to use lower wattage LED's as the experiment, then up the power after success.
Even tho they will be submerged i suspect overheating to be the main hurdle. It should be possible to include a small thermal cut off switch ????.. No idea of additional cost, complexity or practicality but i'm guessing it will be a key to the project and actually speed up the success of this project via less failure rate/frustration. Maybe it will work perfectly without a thermal switch and the power is ok.

The current draw on these is relatively low but can still be significant for small boats if planning on using several. Once you get to 50-100W you can be drawing 5A+ quite easily i imagine....similar to running a 2500l/hr bilge pump continously. Would be worthwhile measuring it as you go for your own peace of mind. This is still relatively small draw tho when you consider burning an older 50-100 halogen spotlight continously can be drawing up to 15A despite the manufaturers claiming 10A or less....even worse if old or the wiring was crap. Many could burn out crappy fag plug fittings and wiring not rated to at least 15A....so that sort of grunt at 100W needs to be at least factored in with wiring on trailerboats, in a similar way we put a bit more thought into bilge pumps which must be treated as needing to fed power and work properly under severe load, rather than manufacturers ratings, Its the heat i'd be concerned with.
I mention the wiring coz as a non safety item i reckon it should never be able to have even the slightest impact on electrics...the sort of thing i might even hook up to a seperate small isolated battery that can be recharged at home.
Looking good Ryanangler. Luv these sort of projects,

Missing_FNQ
18-03-2016, 08:48 AM
Making up a batch of LED pool lights atm. These are probably too large for your application but we use a polycarbonate front lens that acts as a "bucket". The circuit board is placed on a platform about halfway down and resin is placed on the REAR of the board only. This leaves an air gap at the front for heat dissipation and waterproofs the board at the rear. We are only generating approx. 20watts so I think you will have a problem with anything higher if you dont have that gap at the front.

I have a couple of test units here if you would like to try them. Based in Morayfield.

Cheers
Mick

EDIT: Just found a circuit board with built in driver that may suit.
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