DIY LED Grow Light

14. November 2012 by Mike in LED Grow Light  //  Tags:   //   Comments (0)

I'm currently experimenting with growing plants with LEDs.

LEDs have a number of potential advantages for growing :-

  • Indoor growing as no natural light required. This obviously means its easier to keep insects and bacteria/mold that might damage the plants
  • Targeted light spectrum for various stages of plant development
  • Very efficient with low electricity usage
  • Low heat output relative to light when compared to other artificial light sources
  • When combined with hydroponics very fast growth can be achieved

The ability to grow all year round is especially interesting to me living in the UK as we don't have the best weather. I've had very mixed results growing outside in our climate, a few times the strange weather patterns have stunted the growth and caused plants to flower early etc.

DIY LED Grow Light

Drilled Aluminium plate, with two 120mm fans mounted on spacers. Cooling is reversed (i.e air blown upwards for maximum efficiency). LED Drivers not show. The holes visible on this side of the plate were to route the wires from each PCB but I foolishly put them the wrong side on the design - duh!

This light features 24x3W cool white LED's and 24xRed mix (660nm,630nm) with 60 degree emitters. I had to have the LED's manufactured in China as most come with 120 degree or higher emitters which aren't suitable for plant growth (The LEDs in the image are actually 120 degree ones, the 60 degree ones are on another light).
The PCB's are custom designed with aluminium backs. They are held flush to the heat sink with a series of bolts and washers (3 each side). Temperature regulation is extremely good, less than 10c rise above ambient temperature.

The spectral output is no where near correct yet. I'm working on that at the moment!

60 degree on the left, 120 degree on the right. It is better to have the lens as close as possible to the LED to avoid losses. Some people put 60 degree lenses in front of a standard 120 degree LED but that just results in further loss of light.

 

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