CREE LED 3' DIY setup

[marsaiko]

Take your time Apu, this can wait. Greet her a speedy recovery.

[marsaiko]

hey buddy, whats the status

[apuda2010]

Hi Marsaiko,

The set of CREE LEDs and the Meanwell driver has arrived. The 3' heatsinks have also come in. Cables , aluminium frames etc are in.

However , have not been able to do anything further due to my mom's continued ill health...have been in and out of the hospital for the last 2 weeks.

A quick peek into the specs of this build :

14 CREE XP-G Cool White 6500K 3W LEDs
Mean Well ELN-60-48D dimmable driver
2 3' extruded aluminium heatsinks
4mm aluminium top with holes cut for fans
2 Scythe Slipstream thin low noise 120mm fans
1 AC power socket with switch
2 2.5mm DC power jack sockets
Arctic Ceramique heat sink paste
80 degrees lens optics for the LEDs
10k linear potentiometer for dimming
4mm heatshrink tubing
10V 1A DC power supply
2 pin JST connectors - 15 sets
Aluminium frame - 2 inches height , 12"x36".

Will post pictures as I catalog all the stuff. But before that , as promised , some data points on LEDs and the entire objective of the switch over from T5 to LEDs.

And many thanks for the wishes....

[marsaiko]

awesome man, just 42 watt will suffice? why dont you add 7 more,can give you better dimming options and lesser spotlite effect, especially at 80deg(hanging 1ft height?).

Over all a very good choice

And you got all these locally?

[apuda2010]

When you move to LEDs , the measurement seems to change from watts/gallon to lumens/gallon. A 3W LED at a forward voltage of around 3.3 V will blind you with the intensity of light. Having said that , I checked this configuration two times over with the supplier. On both occasions , the supplier confirmed that 14 LEDs are sufficient for light to reach a depth of 2'. Had I been working on a marine setup , I would have needed more LEDs.

I cannot be sure though. Will build the stuff and check this out...but I think my maths so far is correct.

Dimming does not always depend on the number of LEDs. My objective for dimming is to lower the light output during the summer months , when the room temperature in Delhi reaches 32 degress plus sometimes.

The 80 degrees lens was chosen to remove spotlight as much as possible. My tank length is 48". So 7 LEDs per strip means one very 6 inches or so. The fixture will be approximately 6-7 inches above the tank. So total length for light to travel is 30". Therefore , if we use Tan (40) = (Half the spread)/30 inches , then we find that the total spread (=2 x half the spread) equals 50.4 inches. Therefore , each LED will technically cover almost the entire length of the tank. With 7 in a row , the light should be very evenly spread.

But...let's see once the build is ready !! Maybe my calculations need to change.

Where did I get the stuff and for how much ? I will answer this question with lower cost alternatives for new hobbyists at the very end of the journal...so please do bear with me. Lets all learn together how to get this right in terms of build quality and luminosity....what say ?

[asheesh]

very nice, can you post cost of LED , driver and heat sync..
I hope your mom recovers soon

[marsaiko]

superb!!
Just giving a thought, that 50.4 inch would be for middle most LED. So rest of them would throw much light on tank walls?

Regarding dimming, isnt the light going to be cool? why bother about temperature. Or is it to cool the LED equipment.

...but yea, whats works is what is best

[apuda2010]

@Marsaiko...your observation on the 50.4 inch throwing light on the tank walls is correct. In fact , a lot of the room itself will be lit up. Should not be a problem changing the lenses - they come cheap.

The light is not cool. And that's an understatement. If you check the internet for the spec sheet of the XP-G , at 100% relative luminous flux (full brightness) or at full current (1500 mA) , the junction temperature is more than 150 degrees C. Dimming via a linear potentiometer will reduce the forward current and help lower the temperature as well.

@Asheesh - I mentioned at the beginning of this journal and I am mentioning it again...I will post full details of all components including costs at the very end. Please do bear with me.

[marsaiko]

The light is not cool. And that's an understatement. If you check the internet for the spec sheet of the XP-G , at 100% relative luminous flux (full brightness) or at full current (1500 mA) , the junction temperature is more than 150 degrees C. Dimming via a linear potentiometer will reduce the forward current and help lower the temperature as well.

gotcha, so thats with the equipment temperature.

All eyes for the pics

[marsaiko]

hope I am not bugging you very much... but weekend it is.
Any chance for update mate?