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View Full Version : diy submersable led's???


gpx1200
10/27/2011, 12:20 PM
anyone ever try making their own underwater led's ? i'd like to have a few small lights that i cam bury in the back of some caves and rockwork and light them up from inside at night. i'm thinking of trying to encapsulate a cree led in some west system epoxy with some good quality wire, i don't think a heatsink will be needed and i don't think the west systems wil damage the led though i might have to use the special clear hardener to keep it nice and bright. iv'e used west systems before to fix borken plastic and had it in my tank for years with no noticable ill effects, i don't see any reason why it won't work. so has any one tried this or know any reason why i should not?
thanks
chris

havnmonkey
10/27/2011, 08:02 PM
There is a SCUBA dive light that has an LED encased in a clear resin capsule. One end has an o-ring threaded screw that allows for the battery to be replaced. I forget the name but it worked very well as a tank light.

It would work as well for an aquarium, however you'd have a power cable to deal with. Also the clarity of the epoxy and the shape would affect the light output and quality.

It could probably be done easily with one of those bi-pin LEDs you can get from radioshack. I would order an xr-e, xp-e, or xp-g on a 14mm round PCB and set it in a mold the shape of a bullet. Solder the leads secureley and make sure the epoxy clears the edges of the PCB (keeping it out of the salt water). Also you're going to have to choose your external wire carefully. I wouldn't push the LED more than 500ma.

Definitely is very possible.

dogstar74
10/28/2011, 11:01 AM
I think for accent lighting you wouldn't really need to be concerned about clarity or materials. I would make it easy to remove from the tank for periodic lens cleaning. Make sure you can dim the light, as it may be a distraction in a dark room, and remember fish need to sleep too. Lighting up their secure caves where they sleep may not be appreciated in the form of Ich or other stress.

I'd lean toward using red leds as the light spectrum won't effect the fauna of the liverock.

Encase the LED in epoxy like you said, perhaps resin for casting like what can be found at michaels etc would be the best. You could dip the wires in a tool handle plastic to seal them at the base of the resin.

Just some ideas
Aaron

der_wille_zur_macht
10/28/2011, 11:30 AM
I would seriously consider doing this with typical 5mm or 3mm "gumdrop" LEDs instead of HP LEDs (i.e. Crees). A typical HP LED is extremely bright unless at very low currents, and at very low currents it has no advantage over a 5 cent LED.

kcress
10/28/2011, 01:51 PM
I agree with DWZM on LED types and the sleep issue dogstar pointed out.

As for the actual underwater aspect. There are two things you will note if you study professional/industrial cable sealing systems that absolutely positively must be waterproof.

Method 1)
Solid wire is used.
The wire jacket is removed at a point inside the potted area. This allows the waterproofing material to abut and wet the actual single conductors. This blocks any thru-path for water trying to wick its way down the wire. If you used multi-strand wire then the inner faces of the wraps would fail to be wetted and would allow water wicking. So in this case you'd have your wires or cable come down then you'd strip everything off so you had two bare wires. Terminate them to LED leads and then pot everything back up a ways on the cable or wire jackets.

Method 2)
Look at your typical ten dollar power head. Their method is to have the outer jacket continue all the way back out of the water. Then the inside of the cable jacket is considered outside the water. One end is heavily potted and the other end is outside. This method works if you guarantee the one end is always outside, which is assured if there's a power plug on it as in the case of a powerhead.

We await your results!

gpx1200
10/28/2011, 09:12 PM
well i'm drifting away from the idea if useing xre or xpg's simply becouse the meanwell dimable drivers i was thinking if useing along with the third cahnel of my rapid led daylight controler need to have at least 8 led's in the string and i was thinking of 3 or 4 max. so now i'm thinking of modifying some r12 moonlights i have since the crapy moonlight comtroler only works as a dimmer knob now anyway, i have 2 of the 5 led tubes so i'm thinking , open up the plug end and solder the wires directly to the contacts/wires inside, then fill the whole tube with epoxy making shure the wires are solidy sealed in. the only problem with this is the same thing i didn't like about them as moonlights, the light spreads out into a wide flat fan shape that lit a very narow strip across the tank and i don't think this will be any more atractive under the water than above it. so i might try puling the whole lde cluster out of the tube and bending the led's in different directions to get the "ball of light"effect i want