6 Attachment(s)
DIY LED light for planted tanks
Hi All,
Quick DIY on my new light, the purpose of this build is to begin replacing all my CF and T5HO’s with LED’s, reasons being, for running costs (power consumption/ bulbs) and service life.
Heres a quick rundown of the parts list as you can see the total build cost isn’t cheep, but it uses ~70 watts of power and easily outshines a 2x40w T8 and to the human eye a 2x54W T5HO fixture. Once my par meter arrives I wont be surprised if it generates a similar par reading to my 4x54 grolux tubes with spider reflectors (even if the 4x54w's look bighter) but that will have to wait for another time. A massive plus that these particular LED’s are good for 50000-80000 hours (11-18 years @ 12 hours/day)
*DISCLAIMER: This build uses generic high output Chinese LED’s NOT high cost, high quality name brand CREE or Luxeon chips. The blues are a twin epistar chip but I have no idea and no way of finding out what the other are. Data sheets were provided for a baseline product but these LED’s have slightly different properties (viewing angle, wavelength out put, drive current) and so aren’t too usefull . With this in mind any results or measurements from this build are expected to be ~30% lower then similar builds watt for watt that you will read on various reefing forums. Cree and Luxeon do not produce a 430-450nm blue or a 660nm deep red the wavelengths I’m targeting for plant growth. You could build a similar light using a mix or name brand warm whites in place of the reds and name brand cool whites with royal blues but expect to pay $8-$10 per LED vs the price detailed below.
Drivers are all generic low cost Chinese items I’m not expecting a super long service life hence the entire build is based around a fast swap system for failed components. Using higher quality drivers such as Xitanium or Meanwell would get around this but budget at least $60 per driver vs the prices below. LED’s and drivers have been sourced direct from wholesalers in China freight must still be added to the individual unit prices below.
PARTS LIST
RED LED’s 660nm x8 @$1.06 $8.48
BLUE LED’s 440-450nm x4 @$2.70 $10.80
WHITE LED’s 6500k x12 @$1.27 $15.24
60w LED driver(85V 700ma) x1 @$18.74 $18.74
12v driver x1 @$3.95 $3.95
Heat sink x2 @$22.50 $45.00
Brackets 25mmx25mm x8 @$0.45 $1.80
Fans 80mm x4 @$5.95 $35.70
Hobby box x2 @$14.95 $29.90
WAGO connecters x9 @$1.00 $9.00
Aluminium angle 50x25mm x2m @$16.75 $33.50
Aluminium channel 20x20mm x0.4m(1m)@$6.95 $6.95
Wire x2m @$0.25 $0.50
Speaker wire x0.5m(1m) @$0.70 $0.70
Artic aluminia 5g x1 @$8.00 $8.00
Araldite x1 @$7.95 $7.95
Thermal compound x1 @$1 $1.00
Total $237.53
The build is over kill, the heat sinks and fans are way oversized for the LED’s buts its just a concept build the next light will use heat sinks and fans from discontinued CPU’s, plastic hobby boxes instead of aluminium and DIY thermal epoxy, this should bring the build down to ~$130. This will be more inline with a cheep 2x54w T5 unit ($90) and 2 decent plant tubes ($24 ea).
Building the housing was easy enough, I used my compound saw to cut the 20mm channel into 96mm lengths, I had enough from 1m to make 8 sections (enough for 2 lights).
Next I used thermal epoxy (artic alumina) to glue these together to the angle, this will serve has the housing, reflector and anchor points for the light, a few 12mm stainless screws were added for support. The housing was pre drilled to allow for wires to move around the channel as well as to and from the drivers.
The 2 heat sinks were cut in half on the saw and glued to the housing. To save expense I DIY’d the thermal epoxy by mixing equal parts of thermal compound (TIM) from the CPU my last PC build with araldite.
http://discusforums.com/forum/files/geolighttop.jpg
The hobby boxes had 3 and 4 holes drilled in each and were glued in the same manner. One houses the 12v driver used to power the fans, this also houses 5 WAGO’s 3 for ac power (1 live 1 earth 1 neutral) in from the wall to the LED driver and the 12v driver and 2 for the out put from the 12v driver (one for positive one for negative) to the fans. The earth WAGO has a short lead that goes to a screw that keeps the lid on, this serves as an earth point for the housing. The second hobby box houses 4 WAGO’s 2 for the led driver (one positive 1 negative) and 2 for the fans (again 1 positive and 1 negative). The reason for the WAGO’s is in the event of failure of any component it can be removed and replaced (assuming I have parts on hand) in seconds, at least as fast as changing a fluoro tube.
With the housing effectively done I tinned the solder pads on the LED’s before fixing them to the fixture with artic alumina.
http://discusforums.com/forum/files/red-white.jpg
Once glued on I stripped ~3mm of insulation off the end of a length of wire and tinned each end, these were then soldered to the tinned solder pads in series (from + on one LED to – on the next and so on). As the distance between each LED varied I had to do them 1 at a time in future revisions I’ll have the LED’s at a set distance so all the wire can be pre-cut and pre tinned.
http://discusforums.com/forum/files/geolight.jpg
As the blues hadn’t arrived yet these were spliced in after.
Once done I connected the driver to the power cord via WAGO’s and the output to the LED array (also via WAGO’s). Test fire worked a treat.
http://discusforums.com/forum/files/light_739.jpg
Next up the driver was mounted on the back and the 12v power supply hooked up in 1 hobby box.
The fans were mounted on brackets and the brackets glued with araldite to the heat sinks. For cooling I used artic cooling rear case fans these fans move 18+ cfm of air and have less then 16dB(A) when all fans are on they are silent. They have a MTBF of ~30000 hours and so will need replacing before the LED’s but this will be quick and simple. I could have gone with Noctua or Thermal take fans that have a MBTF of over 50000 hours but these would have cost $15-$28 each, with any build you have to do some cost/benefit economising.
Testing the (near) completed unit on the discus tank showed the work in choosing the spectrum of the LED’s paid off, the light is bright and crisp, the blues and reds of the fish are intensified and compared to grolux tube its still warm but not as harsh a “purple”, also there’s no green tint to the water as your get with the hagen lifeglo. With both T8 globes on (80w) the 70w LED light is miles ahead. The shimmer effect out of the tank is very impressive on the next version I’ll space the LED’s closer together so as to get the shimmer in the tank (like a metal halide).
Last stage is to fit the splashguard. I was going to use acrylic but I don’t like how fast it discolours, Lexan or glass will be better options. As this particular light will sit above one of my L number breeding racks on heavy metal brackets 6mm glass will most likely be a more economically viable option.
Next update will be the thermal testing using an IR thermometer to see how well the system deals with the heat from the LED’s, and finally will be the performance test with the PAR meter (when it arrives) to see how this light stands up to at 2x54w T5 with average reflectors and high quality spider reflectors.
