DIY water cooled LED light.

Discussion in 'DIY' started by Marine590622, Apr 18, 2016.

  1. Marine590622

    Marine590622 Executive Board Staff Member

    18000 lumens of 6500K
    4 ft
    ~ $70 in parts.

    The way this would work is you mount a conduit inside of a reflective hood. cap both ends wrap 15 meters of the 5630 led strips around the conduit. Wire it to your power supply and wire a 12 volt water pump to the powersupply. Using rubber tubing you would pump tank water through the conduit and return the heated water to the tank.

    This reduces your heating costs by capturing the waste heat of the leds and using it to heat the tank.

    I have a few questions. Normal electrical conduit would be better then PVC as it will transmit the heat from the LEDS to the water better. The interior of the conduit is coated with Zinc, I am not sure the Zinc is safe for fish. I could also use copper pipe. But I know I would have to age the pipe before it would be fish safe. This would also raise the cost.

    Thoughts? .....
  2. Chuck

    Chuck Well-Known Member

    I'm not a chemist but I believe that zinc will react with water and be toxic. How about flexible plumbers tubing. It should Be safe for fish since it's fine with drinking water. , easy to work with. It won't transfer heat as well as metal, but, should be as good as pvc.
  3. AssassinJimmie

    AssassinJimmie Chris B

    The first time I saw this done they used copper pipe.
  4. Eric N

    Eric N Member

    Aluminum round tubing is available. Stainless steel tubing is also available but harder to bend.
  5. Marine590622

    Marine590622 Executive Board Staff Member

    actually I would use pvc before I would use flexible. But if the zinc is going be toxic I can upgrade the plans to stainless steel, it would add to the cost about $30.oo though. Or just plain steel pipe. The rust would not hurt a planted tank.
  6. Aquaticus

    Aquaticus Administrator


    I've been thinking about this as well. I recently bought a bunch of 3v LEDs, and I was thinking about soldering them to copper pipe and running water through it to cool them and recapture the heat. I was thinking about using a central sump for the collected water and then separate plumbing to run a loop to an aquarium for heat, which I would tie to a temperature controller. Otherwise you may have situations where the water gets too hot.

  7. Megan

    Megan Executive Board Staff Member

    Wow, Eric, that sounds ambitious!
  8. Aquaticus

    Aquaticus Administrator

    It's only ambitious if I do it. I still have to finish my basement and get my fishroom running again! Randy will have his done long before me!
    Megan likes this.
  9. Dave

    Dave Moderator Staff Member

    What is the trade off in recaptured heat, which reduces electrical use, to the electric used by the pump?

    Are you concerned with temp fluctuations when the light goes off and the heater has to take over again?
    Last edited: Apr 25, 2016
  10. Marine590622

    Marine590622 Executive Board Staff Member

    The pump I found is a 12v 400 miliamp pump. As far as temp fluctuations, I would use this in tanks that require a heater, so when the lights are on the pump would be running and I would be capturing waste heat that I would dump back back into the tank... When the lights are off the the heaters would potentially kick in if the temp dropped too low. I am thinking this would work for larger tanks where the waste heat does not have as large of an effect on the block of water in the tank.
  11. Dave

    Dave Moderator Staff Member

    I think I would put this pump on the same timer with the lights. No need to run it when the lights are out. Or, on a delayed timer so that you get the last of the heat before shutting down for the night.
  12. Marine590622

    Marine590622 Executive Board Staff Member

    The pump will be on the same power supply as the leds as par of the light.
  13. steve

    steve Active Member

    ive considered doing a build like this when I put up my big tank. I was planning on using aluminum pieces from 80/20 to put the leds onto and to pump the water through. I would need to seal the ends of the aluminum profiles and then run a copper line down to the sump and just pump the coolant water in a closed loop. I thought about just pumping tank water through the system but the acidity of the water and possibly clogging due to particulates made me change my mind. there are a lot of different aluminum pieces you can order from this company and it is reasonable for aluminum although I'm sure it would be cheaper to just use square aluminum pipe from a local supplier. or local metal supplier to me.
  14. Eric N

    Eric N Member

    I usually go through McMaster-Carr for all my fabrication projects. They are inexpensive and very quick on shipping. They also supply all types of tubing, both plastic and metallic.
  15. Narwhal72

    Narwhal72 Well-Known Member

    A company in Germany tried this a couple of years ago. I saw it featured at Interzoo. In theory it sounds good but in practicality it didn't work out well. The pump consumes energy which negates a big chunk of the gain in efficiency of collecting the waste heat. You can't tie the pump to a filter system because the thermostat needs to shut the pump off when the water temperature gets too high. Metals leaching into the water as well as water leaking into the electronics from the fixture also caused problems. Admittedly this was a very different fixture than what you describe so the water leaking may not be an issue. But any metal will corrode in water to some degree and is best avoided.

    What you describe can definitely be done. But I am not sure there is a worthwhile value in it.
    Dave likes this.
  16. Dragon159

    Dragon159 Executive Board

    I would consider using CPVC as it is used for heat transfer systems. PVC starts to get soft around 100 degrees but CPVC is good to 180. Not that it would see that kind of heat but it isn't too much more cost and wouldn't have any metal to leach into the water. Now you have me really thinking about my big tank.
  17. fishlady

    fishlady Executive Board

    Did anyone ever do this? Was it worth it?

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