DIY LEDs - The write-up

[ReefEnabler]

Got a quick binning question for anybody.

I know that higher number+letter is usally better, but it's also usually true that cooler-whites tend to be the higher bins also.

Looking at the XGP in the following bins for use in growing plants. Wanting slightly warm color and best output:

5B1 R4
4A0 R3

According to the Cree datasheet, 4A0 is ~4500k and is right on the BBL, nice.
5B1 is slightly warmer at ~4250k and also very close to BBL. It also is a higher bin -R4. Also says R3 is ~122lm/w and R4 is ~130.

Both are the same price of 5 bucks on a star if you buy 100 or more from cutter

Obviously I'd want to go with 5B1 R4, but for some reason I feel like double checking that it actually would be brighter and warmer... since usually I don't see higher bins with lower kelvins like this.

 

[mseepman]

Okay, so I have the following configuration for the DIY fixture I'm making:

I will be lighting a 7' tank with this 6' fixture. This will be done in 6' U-Channel, six 2"x1" and 1 x 4"x2". Here is a picture of the aluminum drilled and assembled:

I will be using the BJB solderless connectors and so the hole pattern you see is for the center cluster of LED's shown on the first picture.

My LED's consist of: 98 XP-E RB, 44 XP-G CW, 24 XP-G NW, 12 XP-E Blue.

I have 3 HLG 150H-48B's and 3 ELN 60-48D's on their way to me and will be separating the colors between the drivers but will have to do some parallel strings.

My question is which resistors and fuses should I buy for the XP-G strings where I plan to run them at about 1100ma? I believe the ones mentioned previously by KCRESS are for when you run the string under 1000ma. I could be wrong but would love a link to the right ones at digikey.

Thanks

 

[TheFishMan65]

Still 1 ohm, but probably at least 5 watts. Fuses need to go up to to at least 1.1 amps, but probably either 1.25 or 1.5 amps depending on how safe you want to be.

 

[kcress]

Before I go to the effort of links(which I don't mind) tell me how your math skills are. Can you look a DMM and mentally shift the decimal point somewhere and not be confused doing it?

 

[mseepman]

I would say my math skills are decent...I don't have to practice with them very often anymore though...been out of school 20 years.

 

[mseepman]

I imagine that this fuse would work: http://search.digikey.com/ca/en/products/02511.25MXL/F2323-ND/700722
But I know that KCRESS is light years ahead of me on this electrical stuff and it's better to ask a dumb question than order the wrong stuff in my opinion.

 

[TheFishMan65]

Yep, that fuse look good to me. I expect kcress is wondering about using a .1 ohm resistor. Then when you read the voltage across it you have to multiply by 10 (shift the decimal point) to get the true current reading.

 

[miwoodar]

Great thread(s)! They have been extremely helpful.

I think my design is done but have one lingering question. I want to use a HLG 150-42 to power two parallel strings of 12 XPGs in the 1.0ma range (84 watts, right?). I'm hoping to reserve the extra capacity for another project down the road. I've read that drivers are most efficient when run closer to their rated capacity. My question...am I risking reliability too or am I just wasting a little energy?

 

[Garage1217]

Any of my fellow led people recognize this led? Thinking an osram but not sure the model. It is the size of a xp-g to note but not a cree. Maybe a bit smaller.

 

[kcress]

Fishman has it! That's exactly my point. If you use a 0.1ohm resistor then the resistor can be only a 1/2W resistor but when using the resistor for its designated purpose you have to move the decimal place one to the right to get the correct current measurement.

I suggest this because you're planing to drive over 1A which starts to really dump some power in the resistors.

Use these babies:
http://search.digikey.com/us/en/products/WHAR10FET/WHAR10FECT-ND/678941

I like those terminal blocks to support everything nicely too.

Nice build you got going there.

 

[WingoLED]

Consider using shunt and adjust the circuit current according if you want the strings fail safe.

Guys guys, long time no see!
I am moving next month; sold my tank already, sadly won't have a tank for a while!!

Sensing this upcoming "dry spell", I cannot seem to stop craving another project. Been wanting to get into hydroponic gardening for a while now (done some dabbling in peppers already). So I want to turn the garage of my next house into an Aeroponic grow room! (turns out my RO booster pump is the perfect misting pump also!)



First let me say that most of the gardening forums are a SAD sight when it comes to LED info, dear lord. People start a thread asking if LEDs are good... 3 posts say to get a UFO they're great (lol!!), then three more posts of people saying it can't be done and its too expensive. Then I post some real quick info and stats on a DIY LED rig that BLOWS all the commercial fixtures they are discussing out of the water... and they call me a shilll?!?! lolz!

So annnnnnnyways. I think we all here know that LEDs lighting up a small hydro growspace is really no problem at all.

The best way that I can find to do this would be to use the Meanwell 185-48B (or maybe the bigger 240, but probably not necessary).


My idea would be to run the driver at 3 amps and run 8 parellel strings of 12 LEDs (most likely XPGs, but whatever is cheap on DE when I decide to go forward).

So each LED would be running at 0.375ma, close to optimal. I want to run them low power for Eff and also because I don't want any cooling on the actual aluminum channel. I'd rather avoid potential issues where parts of the frame are cold, parts are warm, and as a result the Vf's drift much more than if you had just let the whole thing reach a nice and even temperature. I'm just guessing this would help the parallel strings based off things I've gleaned reading here. But please tell me if I'm wrong


So I am thinking of putting the 1ohm resistors for monitoring, as well as probably 0.7ma or 1a fuses. Haven't looked into these yet, but the idea would be to allow one or several strings to fail before fuses go, hopefully giving me a chance to see the problem (Thanks Kcress for this idea I read from you years ago).


How does my plan sound? Anybody have any suggestions? Tell me I'm a shill? lol

 

[emora]

Consider using shunt and adjust the circuit current according if you want the strings fail safe.

Could you explain that? How would we implement a "shunt" with several LED series connected in parallel?

I am aware of the use of a shunt as an over voltage protection, but wont our power supplies/drivers (ie Mean Well LED specific gear) take care of the voltage? Am I wrong to be worried only about an excess current situation?

 

[emora]

Sorry. For the double post

 

[TheFishMan65]

I saw somewhere (a thread somewhere) a device put in parallel with each LEDs. The idea was that if the voltage got above X (say 3.5 volts) the device would start to conduct. The idea is that if the LED opens (no longer conducts) the device would start to conduct. This works fine for a open, but if the LED fails in a short then no protection is gained. I think this is what they are referring to.

FWIW the one failure I have had was a short.

 

[2Quills]

I belive your talking about PLED's. And you probably seen it on nuclearheli's thread a short time back. It was one of his more recent updates to his fixture.

 

[pelochas]

any advise on my plan below. its 36 Leds in a 12" x 26" area. 20 Royal Blue, 12 Neutral White, 4 Blue

 

[TheFishMan65]

Is that for the 75? If so I assume you are doing 2. I don't think you have enought LEDs or width if only one fixture. Probably more light than you need, IMHO. Also too wide for a 75. Coverage looks OK to me.

 

[ReefEnabler]

Yea I'm not sure what the point of a shunt would be in a parellel setup where you are way under driving everything.

With the current's I am thinking of running (0.35-0.375), with 8 strings and a 3.9a driver, 5 of the strings could fail WITHOUT having any fuses and the XPGs would still be under their rated 1.5a. So putting a .7-1a quickblow fuse seems like a no brainer here. The odds of 5 full strings failing (which would be required to surpass 1a on the rest), are so low that it's basically not happening without bad wiring or something IMO.

maybe I'm missing something, and there IS a good reason to use a shunt? I just think this current idea is very simple and will work, why complicate it?

 

[2Quills]

Yea I'm not sure what the point of a shunt would be in a parellel setup where you are way under driving everything.

With the current's I am thinking of running (0.35-0.375), with 8 strings and a 3.9a driver, 5 of the strings could fail WITHOUT having any fuses and the XPGs would still be under their rated 1.5a. So putting a .7-1a quickblow fuse seems like a no brainer here. The odds of 5 full strings failing (which would be required to surpass 1a on the rest), are so low that it's basically not happening without bad wiring or something IMO.

maybe I'm missing something, and there IS a good reason to use a shunt? I just think this current idea is very simple and will work, why complicate it?

I believe the point of using the PLED's (led protectors) is so that in the event of a led failure (open short) the current will by pass the led through the pled. The pleds use a certain amount of voltage for which ever size you get. Essentially if a led fails open you won't lose the entire string, just the single led so there's no real rush to take the rig down and fix it right away.

You can check out his video of how it works if you go to post #831 on this page...http://www.reefcentral.com/forums/showthread.php?p=19112440#post19112440

This is technology that's already widely in use in many applications.

 

[pelochas]

Is that for the 75? If so I assume you are doing 2. I don't think you have enought LEDs or width if only one fixture. Probably more light than you need, IMHO. Also too wide for a 75. Coverage looks OK to me.

sorry i need to update my info. its for a 120g tank, 6 footer. it has a wide glass center brace which is killing me. i got a couple of issues, its a tall tank and i want to put some light in the tank's center but not corals will be there. just so that i will have enought light if needed to.

im using 4 of the triple cat4101 drivers, 2 150watt 24v mean well ps. 18 leds per triple cat4101s boards. 2 boards on each power supply.

on the coverage of the whites and blues. not sure if two whites or two blues next to each other will have a too white or too blue effect.