DIY 10-CREE LED Light

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Hi folks! I had some spare time while waiting for my new 2ftx1.5ftx2ft tank to cycle and I decided to try my hands on some techie work.

I planned to run 10 3-watt LEDs in 2 groups of 5.

Some of the things that I ordered:

1. 10 x CREE XR-E 3 Watt LEDs

2. 30watt LED driver that outputs 18V and 2A

3. Acrylic sheets customized to size and pre-drilled with holes

Meanwhile, I went out to Sim Lim to get the following items:

1. Heatsink compound (Epoxy kind)

2. 10 x Heatsink

3. 2 x 80mmx15mm Fan

4. 2 x 80mm fan grill

5. Wires

6. Soldering Iron

7. Solder (Lead-Free)

8. 8 x 4Mx25mm bolts

9. 8 x 4Mx30mm acrylic bolts

10. 2 x Lighted rocker switches

11. 8 x Rubber grommets (washer)

Rest of the items from various shops:

1. 1mm aluminum sheet

2. Pre-cut and drilled acrylic sheets to form body

Now for some pictures!

Got a 1mm thick aluminum sheet to mount the LEDs

Marked the spots to drill holes for wiring. Note that the sheet isn't in great condition since I bought it from a neighbourhood store.

After drilling 4mm holes for wires!

After that, I had to wait for my LEDs and driver to arrive.....

[Guest]

Nice to see another LED D.I.Y Project here.. Keep the photos coming

[Jameshong]

Hi bro,

Welcome to LED D.I.Y club !

Btw, 10 Cree LEDs is insufficient for 2ft tank why not go for 20 ~25 .

[Splutter]

Well actually I've already decommed by marine tank, but I started a new fresh water tank and this is meant for that tank. 10 LEDs should suffice

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Christmas came early! Each CREE LED is individually wrapped in bubble wrap

The LEDs themselves

After mounting them on the aluminum plate via thermal epoxy

The LED driver - unfortunately not very good (I'll explain later)

Heatsinks to be stuck on the back of the aluminum plate

[Thexder]

Where did you order your LEDs from?

[Jameshong]

Where did you order your LEDs from?

The packaging is so familiar to me....I think he must be ordering either from Dealextreme.com or Kaidomain.com .

[Splutter]

Correct bro, its from Deal Extreme. I think it's the cheapest I could find already. I still have 10 extra LEDs on hand if anybody wants to get them.

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Testing connection - it works!

The 2 fans I got to cool things down. Both are rated at 12V, 0.09A from Nidec

The customised acrylic pieces - they cost quite a bit to order, nearly $130 =(

Screwing in my fans after drilling the mounting holes myself. I put in rubber grommets to dampen the vibrations as well.

Snapping in the lighted rocker switches. One for the lights and one for the fans.

[sherman]

Bro how come you choose 18 v led driver?

18 v can only run 4 leds.

Also 1 mm aluminium plate is a bit too thin you need at least 2 mm with proper

heat sink

[Jameshong]

The customised acrylic pieces - they cost quite a bit to order, nearly $130 =(

Too many holes drilled by DAMA that why the cost is so expensive ! Price will be double if you ask them to smoothen the edge of all the acrylic sheet .

For me, I drilled small holes myself so It's cost me only 77 buck so next time DIY yourself.

Btw, your customized acrylic sheets look familar !

[Splutter]

Sherman, each LED voltage drop is between 3.3v - 3.7v, depending on what current you want to drive it at. So 5 x 3.3 = 16.5v and 5 x 3.7 = 18.5v. It's sufficient to drive.

Ideally I would want to get a 3mm aluminum plate, but unfortunately my neighbourhood store only has 1mm. I was a little hesitant to get it from the industrial areas as it's just too much trouble. 1mm was more than strong enough to hold everything for a 2ft setup. I would highly suggest something thicker if it's going to be bigger in size.

Jameshong, well I got pretty inspired by your post =P But I think my design is easier as I tried to minimize acrylic work on my end. I'm very new to working on this and I even broke a few drill bits trying to drill some small holes. Can't imagine what damage I'll cause if I tried to drill the 10mm and 65mm holes myself, haha.

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So anyway, I ditched the idea of using this voltage regulator as the output voltage wasn't very stable. As I was running the circuit without any current limiting resistor, it led to unstable current load as well. The regulator died out after a while. I went back to the drawing table and opted for a dual AC/DC switching supply instead where I hooked up 5 LEDs + a resistor to a single regulator at 24v, 700mA.

Some of my calculations:

Voltage drop across 1 LED at 700mA = 3.5v

Voltage drop across 5 LEDs at 700mA = 5 x 3.5 = 17.5v

Voltage across resistor required = 24v - 17.5v = 6.5v

Resistance of resistor required = 6.5v/700mA = 9.285ohms

Wattage of resistor required = 6.5v x 700mA = 4.55w

Resistor eventually used : 10 ohms, 10 watts as I wanted to be on the safe side for heat dissipation

I also bought 2 new Mean Well switching regulators at SLT again.

Wired up everything according to this circuit diagram:

[sherman]

Bro ,

Using resistor you will not get constant current.

Remember to consider temperature changes,resistance changes ,current and voltage changes

are all related.

Your led life span will be shorten with the current changes due to temperature and voltage

changes during light up.

Regards

[Splutter]

sherman - I understand those. However, I'm driving the LEDs at 700mA now instead of the original 1000mA. Will there be room to play for the fluctuations?

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My girlfriend helped me with the acrylic construction and I think she did a very nice job =)

The acrylic bolts I got to screw in the tail plates

The new 10 Ohm, 10 Watt resistors I got to limit current

The new Mean Well voltage regulators - 24v, 700mA

How everything looks after powering up!

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More views of the final product =)

[RockyBoy]

nicely done!!

[subxero]

Nice setup

[peacemaker]

Nice build and nice tank!

[Splutter]

Thanks bro!

Still think it pales in comparison to so many other DIYs here though. Someday I'll add a PWM when I come back to marine =)