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Discussion Starter · #1 ·
Recently I build a pendant LED light for my ADA mini M. I like to share my build in the hope it might help other DIY enthusiasts. I myself have learned a lot from other people who posted their build on this and other forums. The main reasons to build a pedant LED light myself are that I love to making things, to save money and to have a light which meet all my requirements. English is not my native language so on forehand my apologies for the mistakes in spelling and grammar.

Hardware
As a light source I choose to use five cool white Cree XPG R5 LEDs. As a power source I used two 900 mA constant current LED drivers. One drives two LEDs, the other three. The main reason to use two LED drivers was because I was (and still am) afraid that five Cree XML LEDs might be a bit too much. In this way I can turn on five three or two LEDs by simply turning on one of the two or both drivers. This, in combination with the ability to raise the pendant light makes the light intensity easily adjustable without the use of expensive dimmable LED drivers.

Specifications
Each LED has a power consumption of approximately 2.8W (rated at 900mA) and a brightness of approximately 320lm. So the total fixture has a power consumption of 14W and a brightness of 1600lm. This is comparable to the ADA aquasky 361, which had a power consumption of 17W and a brightness of 1450-1550 lumens. This is not surprisingly because I intended to match the specifications of this LED light.

Design
I really like the slim design of the ADA aquasky series but I prefer the looks of a pendant light. Also, I think it looks messy when the power cord is visible, as with the ADA aquasky. I tried to combine those items in my design while keeping the fixture fairly easy to build with standard tools.

My design is basically a sandwich of three 3mm thick aluminum plates, fully enclosing the five LEDs. The top plate contains four holes for the suspension of the light by four thin wires witch simultaneously act as power cords for the LEDs. The five LEDs are glued with thermal paste to the underside of the top plate which acts as a heat sink. The middle plate has a slot in order to house the LEDs. The lower plate has five holes in it in order to allow the light to the outside. The top plate is glued to the middle plate and the middle plate is screwed to the lower plate.









Expenses
- 2 10watt LED drivers 11 USD
- 5 cree XPG R5 12 USD
- 1 Thermal Conductive plaster 1 USD
- Aluminum 10 USD
- Total expense 34 USD
Regarding the total expense, it should be taken into account that I already had wire, solder, screws, glue, etc lying around. The total expense can significantly increase if you have to buy such miscellaneous items.

The final result













I’m very happy with the final result. I like how the minimalistic design looks in real life; also the finishing of the fixture looks pretty neat. The top plate (heatsink) gets quite hot to the touch though, but is still touchable; I guess it is about 45 Celsius when the LEDs are on. The five LEDs are incredibly bright and I am concerned that it might be a bit too much for the small Mini M. I intend to have a high tech setup but I have no experience with this whatsoever. Maybe someone can give me some advice on this point?
 

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Very nice aesthetics. Good job!

I like the way the power cords doubles as a hanging kit.

If you paint the reflecting surface in the bottom piece matte white maybe you get a little more light out of it. Just a thought.

Did you use thermal paste/glue between all three layers?

Edit: If to bright/hot, you could just buy the dimmable driver you mentioned and voila, problem solved.
 

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Very nice. I like the look you got as well.
But then there are always those who may not like the look of the bare metal? Very easy for them to add a few strips of wood trim around the edge to make it what they like. Too many settle for what is sold rather than building what they want. Very nice of you to share.
Never be too concerned about the language question. Your posting is far better than some that use English all the time!
 

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Really nice work. This is just my style and will probably try to copy your concept. ;) I had the same idea about hanging the lamp in the cables instead of having both hanging wires and cables which does not look as nice. I wonder why none of the expensive lamps are build this way.

Does it stay cool enough without fans after running for several hours?


Regards,
Henrik
 

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Discussion Starter · #6 ·
Thanks for the compliments!

@matsnork: The reflecting surface is just a 120 degree angle hole in order to maximally let out the light emitted by the LEDs at an 120 degree beam. I agree with you that the dimmable driver is the nicest option, also the most expensive unfortunately:(

@Zahlon: If you keep touching it for a longer period of time (after the light has been on for a few hours) it feels unconformable hot but not so much it hurts... So my guess it gets about 45 degrees Celcius.
 

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Thanks for the compliments!

@matsnork: The reflecting surface is just a 120 degree angle hole in order to maximally let out the light emitted by the LEDs at an 120 degree beam. I agree with you that the dimmable driver is the nicest option, also the most expensive unfortunately:(

@Zahlon: If you keep touching it for a longer period of time (after the light has been on for a few hours) it feels unconformable hot but not so much it hurts... So my guess it gets about 45 degrees Celcius.
First let me start by saying beautiful work...

That said, a bit of a minor question, Why did you stick w/ the 120 degree angle?.. As a minor point.. doing say 90 degree may have helped concentrate that light over that tank and at that height..

It looks like you get a lot of spillage that could have possibly been avoided..

Again this is only a minor point... and I'd make the same comment about the Aquasky..Using 3w LED and the native 120degree angle, never warmed to lenses myself, I do understand the difficulty and also the need (nothing worse than "dead spots" near the top) of a good balance here..
Every few months I contemplate raising or lowering the fixtures since most of the time I'm too lazy to "skirt" them.

BTW: It certainly is enough light... ;)

 

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Discussion Starter · #9 ·
First let me start by saying beautiful work...

That said, a bit of a minor question, Why did you stick w/ the 120 degree angle?.. As a minor point.. doing say 90 degree may have helped concentrate that light over that tank and at that height..

It looks like you get a lot of spillage that could have possibly been avoided..

Again this is only a minor point... and I'd make the same comment about the Aquasky..Using 3w LED and the native 120degree angle, never warmed to lenses myself, I do understand the difficulty and also the need (nothing worse than "dead spots" near the top) of a good balance here..
Every few months I contemplate raising or lowering the fixtures since most of the time I'm too lazy to "skirt" them.

BTW: It certainly is enough light... ;)
Exactly. I was concerned about the spread of the light and I knew that it would have enough intensity for the mini M. However, the main reason not to use lenses was because of their size. Lenses are about 13mm adding this to the 3mm top plate and the 1.5 mm LED whould give a thickness of the fixture of about 18mm which is twice the 9mm thickness it has now. A similar choice was not to use cooling fins and accept that it might get a little warmer.
 

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Discussion Starter · #10 ·
Rinna, that is a nice looking light. did you machine the parts yourself? how did you protect the solder connections from making contact with the aluminum piece that covers the LEDs?
The parts were not machined.

The aluminium plates were scrap metal from metal shop and the guy there was willing to cut the crap plate into the correct size for a few euro. I made the slot in the middle plate by drilling four holes in the corners, then using the dremel tool and a saw to cut out the rest. I made it a little smaller at first and then used the file to get to the exact dimension. Same for the outside of the middle plate. What i did used though was a column drill.

In order to isolate the solder I stuck on "electric insulating tape" to the topside of the lower plate at the same place as the slot in the middle plate. (ducktape or something like that would work to). Then I drilled out the holes again for the LEDs.
 

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Did you consider using 5w leds instead of 3w? Or would require fans or the led drivers would cost way more? Speaking of led drivers. Can you specify which drivers you are using?

What are the dimensions of the alu plates besides they are 3mm thick?


Regards,
Zahlon
 

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Discussion Starter · #13 ·
Nicely done with just a dremel and a column drill.

I´m guessing that the angle of the reflectors/holes were limited to the drillbit used? Maybe you could mount a plastic lens over each led.
Indeed, drillbits have a top angle of 120 degrees. I used a 20mm drill bit for those holes. Plastic lenses would stick out at least 10 mm at the underside of the fixture which would be much less aesthetically.

Bump:
Did you consider using 5w leds instead of 3w? Or would require fans or the led drivers would cost way more? Speaking of led drivers. Can you specify which drivers you are using?

What are the dimensions of the alu plates besides they are 3mm thick?


Regards,
Zahlon
These are in fact 5w LEDs which I drive at 900mA in stead of 1500mA. The main reason to use these LEDs was because I found a good deal on ebay.

Specs of the drivers: IN: AC100-240V; 50-60Hz OUT: DC 6-12V; 900mA
I used two of them (one for three the other for two LEDS) to be able to control the light intensity.

Outer dimensions of the plates: Upper and lower 280x68; middle 274x62 (mm)
 

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Discussion Starter · #16 ·
rinna,

would you mind explaining how you made the incoming wiring seem to be non-exsistant? the only thing i see is the 4 wires that the light hangs from.
Sure, the four wires the light hangs from are in fact the in- and out coming electric wiring. Two positive (from the drivers to the LEDS) wires on the left and two negative (from the LEDs back to the drivers) wires on the right.

The picture below explains the wiring in the fixture. Dashed lines are one LED driver, straight lines the other LED driver.



The wire I used is from some old earphones (mind that these are very thin and thus only can handle low amps and are very difficult to solder)
 
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