DIY LEDs - The write-up

[der_wille_zur_macht]

That is probably a safe estimate. Keep in mind that Vf can vary significantly so it's best to allow for flexibility (i.e. don't back yourself into a corner using exact theoretical numbers). If you have an application that requires exact precision, get your hands on the actual LEDs you will use and measure Vf at desired operation conditions (current, temperature).

 

[brassmonkyballs]

FWIW I have wired a lot of XPEs over the last six months for me and others and they tend to run on average Vf of 3.1V @ 1000ma. The strings in my tank are 4 x 11 in series on a 185-42...each string sees 1100ma and the string voltage is around 34.1V. Individual LEDs within a string have ranged from 3.04 to 3.34 at those max settings with the 3.3s being outliers...most are in the 3.1x range. The last 3 fixtures I've helped folks with have had similar readings.

Again this is just my personal experience with a bunch of LEDs.

 

[S2minute]

Thanks Monky . I was just going off of what was stated in the Cree site. Personal exp. is always best.

 

[Volkster]

Wanted to share my success and say thanks to all that helped me.

I decided to go with 4 strings of 20 @ 60/40 compared with what I had posted earlier :http://www.reefcentral.com/forums/showthread.php?t=1678127&page=289) Post 7220

Here's my design:

Here's the final product over the tank :dance:

Close-ups:

Fan's run super quiet (2600rpm) and keep the heat sinks very cool.

Wired (Manual Dimming):

 

[Volkster]

Own Moon Light:

Ambient light from the fan LED's give just enough light for a moon light :thumbsup:

Blues @ 50% (550 mA) | Whites @ 1% (11mA):

Blues @ 1% | Whites @ 50%:

Sweet Spot - Blues 70% (750 mA) / Whites 50% (550 mA):

I'm really impressed with the CREE LED's and the colouration.

 

[Volkster]

Balanced Readings:

My next project is to hook this puppy to an ardunio diy controller...but first need to reaquaint myself with the family

So again thanks for those who helped and for this super thread!!

Here's my journal: http://www.reefreflections.co.nz/yo...tos/682-v%F6lksters-650l-zeovit-reef-tank.htm

 

[brassmonkyballs]

nice work Volkster!

I also see your typical Vf on the XPEs seems to be in the 3.1V range as well

 

[Volkster]

Yea! And the odd one that is 3.4V? Any reason why this would be?

Even if I move it to a string with lower/high draw it stays the same?

 

[kcress]

!!! What a nice clean build! Crazy data payload too. Nice. I love how your first attempt went backwards... Resistors made it easy to check didn't they, huh, huh, right? See. I told you.



That high LED is just a high LED. Means it's a lousy one with low efficiency. It will be the first to fail in the years ahead because it will be running hotter for all those years.


Was that one string really 300mA when the others were 500?

 

[Volkster]

Thanks

Yea it was? And the way I balanced my strings was to tackel the lowest one first. I took the lowest (measured voltage) LED from the highest string and swapped it out with the highest LED in the low sting. I did this one at a time. Then moved to the next string and so on...

When they where all with-in 50-70mA of one another I took the middle measured LED and swapped them around. This is how I managed to get the strings so close to one another

Only thing now is after 1 week they have all drifted and I have one sting outside of the recommended 30mA real pita as I'll need to balance them again and it ain't a quick job.

... when I get time again :S

 

[kcress]

Tiz ok. Leave it for a while so the age drifting tapers off. OH! And make sure your testing and comparisons are all done after the unit has reached thermal equilibrium. For yours I'd say an hour or two.

 

[Volkster]

So when I balance them next you mean to measure each LED & String after an hour once turned on, then swap a few LED's and wait an hour again before testing and swapping?

 

[jamesbm1001]

I don't know if this has been addressed, discussed, attempted, or dismissed previously as I haven't been able to find any posts about it, but please, stick with me.

I happened across a PFO solaris i4, 24 inch unit at a local shop. It was used and had a few led's that had burned out. the controller, display, fans and power supply were all working, so for $120 I figured, meh. I've been wanting to build an LED setup for my new tank for some time now and I figured that if nothing else it's a relatively inexpensive unit to tinker with and figure out how it all works.

I switched a few of the LED boards around to verify that it was the LEDs and not the drivers that were blown, and it was. So I currently have 4 power supplies (the shop keeper wanted me to take the 3 dead ones as well as the working one), 10 drivers, and 8 complete led boards plus the heatsinks, fans, housing, and microprocessor. I'm wondering, are the drivers they used any good/worth keeping? If not, can the controller operate a buckpuck? I never planned on using the luxeon K2's in the fixture but swapping out for Cree's so no worries there about how crappy they are. I have not been able to find out any technical data about the signal being sent to the drivers from the controller i.e. is it 0-5v or 0-10v, pwm, yada yada. If it is possible to swap off the shelf buckpuck drivers into this unit, I'll be extremely happy because each controller has 6 ports to attach the led matrix to so I could feasibly expand this to a 100 led fixture.

Now I'm sure I'll have someone wondering "why", but if I already have a controller capable of doing this, why not? I know I'd have to add a larger power supply, but that's okay. It won't hurt my feelings any if this is a non-starter. Please feel free to lend opinions, criticisms, or advice.

P.S-My tank is of unusual proportions, it is 65Lx24Wx15H, so I'm not planning on using optics at all.

 

[rhwimmers]

Getting ready to get my DIY project running, looking for some thoughts on my setup:
120 gallon (60"x18.5"x26")- This is all from rapidled

DDC-01 PWM Controller
48 Ultra Premium LED DIY Kit with Dimmable Drivers (has 24 cool white cree xp-g r5 leds)
12 Ultra Premium LED DIY Kit with Dimmable Drivers (has 24 royal blue cree xp-e r5 leds)
4.25" x 23" Aluminum Heat Sink (2)
I will go with the 60 degree lenses. If I am planning on getting a controller to control my vortechs and a few other devices, should I skip out on their controller and get a different one that can control these LEDs?
Not sure what to affix the heat sink to yet, I have 2x4s but I would like something that looks a little nicer and have it be on an adjustable chain or something for tank maintenance etc. I have just over 2' of clearance between water level and where the "hood" can be.
Also, thought about putting in some green and/or red in...thoughts?

 

[TheFishMan65]

There is something wrong in your counts for LEDs. I can't see a 12 Ultra premium containing 24 LEDs . Are you doing 24 white and 36 royal?

To use the DDC you need the P ELN driver (IIRC that is what the kit come with), but most reef controllers do 0-10 volts and need the D version. So step one is figure out what you are getting for the vortechs then go from there.

I would get warm whites or a mix and see how you like it. It should be easier to mix then one or two green and red.

 

[der_wille_zur_macht]

So when I balance them next you mean to measure each LED & String after an hour once turned on, then swap a few LED's and wait an hour again before testing and swapping?

Kinda. If I were in your shoes, I would warm up the whole fixture, measure everything, then sit down with all the numbers and plan "enough" swaps to balance everything. Do the swaps, turn it back on, warm it up, and check again. If you get lucky I bet you'll find you can nail it in one or two iterations. I don't suspect you'll have to sit there all weekend swapping, warming, swapping, warming...

I don't know if this has been addressed, discussed, attempted, or dismissed previously as I haven't been able to find any posts about it, but please, stick with me.

I happened across a PFO solaris i4, 24 inch unit at a local shop.

I know there have been one or two people that have "rebuilt" those units and reported about it in this thread but it's probably a year or so ago, so it's buried in hundreds of pages by now. Maybe try a google search of the forum (since the built in search tends to be poor for these sort of specific things).

 

[rhwimmers]

Meant to say the following

48 Ultra Premium LED DIY Kit with Dimmable Drivers (has 24 cool white cree xp-g r5 leds, and has 24 royal blue cree xp-e r5 leds)
12 Ultra Premium LED DIY Kit with Dimmable Drivers (has 6 royal blue cree xp-e r5 leds, 6 whites..

 

[TheFishMan65]

I just read what I wrote I meant neutrals not warm. Although some like warm. I still need to do some testing so i can't give a personal recommendation.

I would go a little heavier one the blues.

 

[Quartapound]

Meant to say the following

48 Ultra Premium LED DIY Kit with Dimmable Drivers (has 24 cool white cree xp-g r5 leds, and has 24 royal blue cree xp-e r5 leds)
12 Ultra Premium LED DIY Kit with Dimmable Drivers (has 6 royal blue cree xp-e r5 leds, 6 whites..

you don't need to stick with the color ratio's that RapidLED gives you....

you can customize your order.

Most people recommend a 2:1 royal blue/white ratio

just put the number of each that you want in the "special instructions/comments" area when you check out

 

[rhwimmers]

Ok so that is where I can put in to have a few red/green ones I guess. My last tank I had 2x250w halides that were 55 or 65k (pretty yellow without any actinic) then I had 2 VHO actinic and it was a pretty nice color, but I think I prefer a little more blue. The red/green are just for experiments to see if I get better growth or color from certain things. I guess I would have to wire each of those colors differently if I wanted to keep it separate, right? So I would then need 4 "dials" one for white, blue, red, green? Seems like that might not be worth it, just mix some red/green in on the blue/white strands?