DIY LEDs - The write-up

[brassmonkyballs]

i'd like to tap on the experience that you guys have here.
is there a big difference in luminous intensity by running an XPE RB @ 625mA compared to running @ 750 mA.
I believe most of the DIY'ers are running theirs at 750mA?

depends on the exact Bin and they do vary a bit but if a current XPE they should be D316 which have a minimum 500mw radiant flux at 350ma. At 625ma radiant flux is approximately 160% of the min or 800mw and at 750ma its about 190% of the min or 950mw so its approximately 19% more radiant flux at 750ma vs 625ma.

The curves can be found here at the bottom of page 10 http://www.cree.com/products/pdf/XLampXP-E.pdf

 

[jkopp36]

Ok, I cannot get the HLG-240 to dim properly.

Sceanrio: 100K pot on dim circuit (verified pot with meter) -> start with pot all the way down -> driver is at approx 265mA per string -> turn pot up and have to get about half way to full before current increases -> current gets to full within a tiny bit more movement on the pot -> putting out around 750mA at full.

I am unable to get the driver to run at less than full using DC voltage on the dimming circuit but I have only been able to get down to 0.8v so something is definitely wrong.

I think I blew the fuses a couple times before because the strings were not balanced and the highest current string would blow then the rest would follow. Now that they are closer to balanced I have not had a problem blowing fuses. I was surprises how far off the strings were but equally surprised how much closer they would be after swapping just a couple LEDs.

Any last minute input before I order a new 240? FishMan mentioned something about total voltage being low. I measured 44 volts with the LEDs running at 700mA last night.

Ready to get this done and hung!

 

[widmer]

OK just thought I would throw this up here, my new fixture is in the air.

No build thread yet, I still have to make the enclosure & barn door shades. Notice the light on the ceiling, which was reflected back up @ the fixture, there's no water in the tank yet.

 

[jgwinner]

Looks great!

How did you calculate the fixture size? Looks like a good match with the tank. What size tank is that?

== John ==​

 

[widmer]

I was surprises how far off the strings were but equally surprised how much closer they would be after swapping just a couple LEDs.

It is kind of amazing, when I first set up two parallel strings of 12x royal blue XPE, one was running 200 mA more than the other when the driver was on full blast. After minimal playing around I got them to within 50 mA @ full current which is just fine by me.

 

[TheFishMan65]

jkopp, I agree it sounds bad. The 44 is a little low, but should not be a problem. You might consider the 48 as it will give you a little more current.

widmer, what angle optics are those? and how high up?

 

[widmer]

Thanks, the tank is a custom dimension glass cages 48" x 15" x 12" high rimless made out of 1/2" starphire 3 sides. The display ATS will be sitting right next to it on the right.

As far as calculating fixture size, I simply went with a standard 3-foot length, knowing ahead of time what optics I would be using and what height it would be at, in order to minimize light spill outside of the walls of the tank. The fixture will be packaged into a 3" x 4" x 38" enclosure.

 

[widmer]

The XPGs have 12 degree optics strapped on and the XPEs have 10 degrees. It is about 3.5 feet from the water surface and 4.5 feet from the sand bed...

 

[TheFishMan65]

I tried some either 5 or 10 degree optics for the XR-E and was disappointed in the light pattern (bright and dim spots). Whose are these and do you have a picture of the spread of one LEDs?

 

[kcress]

It boiled all the water out!!? That's too dangerous. You should send it to me for safe disposal.

jkopp36; First turn the unit all the way up and measure the voltage across the whole array. In other words, what is the driver putting out, voltage wise, when you have it turned fully up?

 

[jkopp36]

jkopp36; First turn the unit all the way up and measure the voltage across the whole array. In other words, what is the driver putting out, voltage wise, when you have it turned fully up?

44 volts. I'll double check that is at fully turned up tonight but I'm pretty sure it is.

 

[jkopp36]

I ordered a new 240 and took your suggestion of going with the 48v version FishMan. Now, if that's the issue, what to do with a 240-54 that runs fine if dimming is not a big issue? hmmm...

 

[TheFishMan65]

Ats

 

[widmer]

I tried some either 5 or 10 degree optics for the XR-E and was disappointed in the light pattern (bright and dim spots). Whose are these and do you have a picture of the spread of one LEDs?

XP-G: http://www.ledsupply.com/10138.php
XP-E: http://www.ledsupply.com/10194.php

I bought one of every optic that LEDSupply sells for both XP-E and XP-G. I would have gone with the very tightest, except their pattern was definitely spotty. Alas, the frosted narrow have an excellent even beam, so that's OK.

 

[Frode]

Which LED's to go with my T5

Which LED's to go with my T5

Hello there,

I am following this thread for a while and it helped me very much when I made my first DIY LED fixture more then a year ago. Oh my, how much info has passed since then. There are certainly some helpfull experts around here.

That's why I would like to put forward someything I am dubbing about.

I've got a 6 x 39 Watt T5 ATI Sun Power fixture along with my DIY LED.

It's time for a change of the bulbs, and I plan to exchange two of the T5 bulbs for LED's :spin1:

I still got 10 CREE XP-G Cool White waiting in a box, and two Meanwell ELN 60-48 P (should have been D-versions I can dimm with my IKS Aquastar, so I never used them).

So I thought of putting this to use; making two series of 14 LED's on a alu bar. 14 on each Meanwell, driven at 1,3A. Each bar could replace 1 T5 of 39 Watt in the fixture.

Now I still got to add 18 LED's...and the question is, which should I take???
I could go al white and balance the overall collour with Blue/Actinic T5.
Or I could add 14 RB LED's. And adjust my T5 bulbs accordingly.

Going White, I could add 18 CREE XM-L and mix them in series with the XP-G. Or should I go for XP-G only in a series?
The XM-L 's would give me more Lumen per Watt, but what about PAR per Watt?

So far the options for the LED's, then the optics...
to mix out the light of the LED's evenly with the light form the T5 I think I should not go any narrower then 80 degrees optics. Anyone comments on that?

I'm looking forward to your input.

Best Regards,
Frode

 

[TheFishMan65]

Frode,

If you are taking out two 39 watt T5s you really only need about 9 LEDs to replace them.

XM-L will be brighter, but after running some number it appears it is cheaper to run 2 XP-G than 1 XM-L with twice the current. The XP-G produce a little more light with a little less electricity. Now if you kept the count the same the XM-L are better, but the price difference is quite a bit.

If you do add LEDs I would match the color to the 2 bulbs you are taking out. If you don't you have to change/buy T5 which I thought you are trying to avoid.

 

[CJO]

I'd also add that you probably don't want to run the XP-Gs at 1.4A unless you have a lot of cooling. I'd run closer to 1A to be safe.

CJ

 

[BPro32]

I'm thinking about diy'ing some led's for my new tank (60x30x25) instead of buying a new t5 fixture. My guess is I would use 72 led's total does that sound right? How should I setup the heat sinks?

 

[Frode]

Frode,

If you are taking out two 39 watt T5s you really only need about 9 LEDs to replace them.

XM-L will be brighter, but after running some number it appears it is cheaper to run 2 XP-G than 1 XM-L with twice the current. The XP-G produce a little more light with a little less electricity. Now if you kept the count the same the XM-L are better, but the price difference is quite a bit.

If you do add LEDs I would match the color to the 2 bulbs you are taking out. If you don't you have to change/buy T5 which I thought you are trying to avoid.

Thanks for your thoughts and numbers FishMan. Indeed the XP-G's are cheaper to buy (saves € 2,- a LED), but are they really a better choice in value for money on the long run?

I calculated for my Meanwell ELN 60-48:
14 XP-G at 1,3 A / 3,4 Vf / 61,9 Watt / 5838 lumen
14 XM-T6 at 1,3 A / 3,05 Vf / 59,5 Watt / 7350 Lumen

Offcourse, allready having 10 XP-G makes that choice a lot cheaper...but could I just mix them with 18 XM-L? Guess that would give no problem if I don't make mixed parallel strings (which I won't).

I know I don't need 14 LED's to replace one 39W T5. But now I am lighting my 48"x 24"x 24" tank with the 6 x 39W T5 fixture AND my DIY LED (32 CREE XR-E, 50/50 W/RB at 700 mA).
I hope to be able to light this tank just with the pimped T5-fixture;
so 4 x T5 39 W and 28(?) LED's.

The colour question still stands. I need to exchange all my T5 bulbs soon (older then 16 months allready...) so I now have a change to adjust the colours of the T5 to match whatever LED's I choose.

I'd also add that you probably don't want to run the XP-Gs at 1.4A unless you have a lot of cooling. I'd run closer to 1A to be safe.

CJ

That's is a good point CJ. The T5 fixture is probably not a LED friendly environment. Originaly the fixture had one 2" fan for active cooling, I allready replaced that by three 3" fans. T5-bulbs like cooling to.

This would put the favour to the XM-L I guess, because I would not push those to the egde driving them at 1,3 A

 

[Frode]

correction on last post

I calculated for my Meanwell ELN 60-48:
14 XP-G at 1,3 A / 3,4 Vf / 61,9 Watt / 5838 lumen
15 XM-T6 at 1,3 A / 3,05 Vf / 59,5 Watt / 7350 Lumen (note, 1 led more!)