DIY LEDs - The write-up
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Gold Stripe
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Totally green at this but wanting to try my hand at DIY. Unfortunately this thread is soooooo long I have not been able to read it all. I think I have everything ironed out except for 1 question.
Why does everything revolve around multiples of 12 with LEDs? I will be using Mean Well ELN 60 - 48D drivers dimmed by an Apex and everyone keeps saying I need to have 12 LEDs per driver. I was originally looking at 4 strings of 10. Why 12? The ratings I see say 8-14 so why is 12 the magic number?
Why does everything revolve around multiples of 12 with LEDs? I will be using Mean Well ELN 60 - 48D drivers dimmed by an Apex and everyone keeps saying I need to have 12 LEDs per driver. I was originally looking at 4 strings of 10. Why 12? The ratings I see say 8-14 so why is 12 the magic number?
TheFishMan65
New member
There is a link to a summary of this thread on my home page that may answer (or remind you) future questions.
History and now the lesson. Way way back in the dark ages the most efficient LEDs was the Cree XR-E. IIRC they ran 3.5-3.8 volts. Well since the ELN only goes to 48 volts (or designed for) that left us with 12 LEDs. The number of LEDs is dependent on the forward voltage at the current you want to run. The XP seem to be closer to 14 as the limit although I am not sure you can max out the current, but close. The new XM-L are 2.9 volts at (700ma) I believe so you could get 16 of those on there. Of course you can run them at a much higher current than the previous Cree LEDs.
History and now the lesson. Way way back in the dark ages the most efficient LEDs was the Cree XR-E. IIRC they ran 3.5-3.8 volts. Well since the ELN only goes to 48 volts (or designed for) that left us with 12 LEDs. The number of LEDs is dependent on the forward voltage at the current you want to run. The XP seem to be closer to 14 as the limit although I am not sure you can max out the current, but close. The new XM-L are 2.9 volts at (700ma) I believe so you could get 16 of those on there. Of course you can run them at a much higher current than the previous Cree LEDs.
brassmonkyballs
BMB
HLG 120 Driver
HLG 120 Driver
Finished one of my fixtures today and got to fire up an HLG 120. For this build I am using low cost chinese made LEDs which are obviously 5 year old technology but they have wonderful color temp, and are dirt cheap...just sadly inefficient. Anyhow I am running 40 in 4 strings off the HLG 42-120. The strings balance nicely on 1st try reading 710, 720, 730, & 740ma.....add that all up and its exactly 2.9A....exact rating of the driver. Each string is running right around 36.1V give or take a tenth.
Couple observations of the driver....LED power and dimming wiring is 16 awg compared to the ELNs which are 22 I believe. Dimming is very very smooth and no dead spot before you get lights. In fact the dimmer won't turn them off.....not sure why but in the lowest setting my meter showed 0.04A which doesn't make sense and the LEDs are on very low.... I didn't think to switch it to the 200ma range at the time because I was going through each string. So the only way to turn off the HLG for now is remove main power. I'll have to take more readings with the dimmer all the way off and see if I can make any sense of it. But the dimming is extremely smooth.
Finally, the driver runs very cool compared to the ELNs I have. So far so good.
Kcress if you have any thoughts on the dimmer low setting let me know.
HLG 120 Driver
Finished one of my fixtures today and got to fire up an HLG 120. For this build I am using low cost chinese made LEDs which are obviously 5 year old technology but they have wonderful color temp, and are dirt cheap...just sadly inefficient. Anyhow I am running 40 in 4 strings off the HLG 42-120. The strings balance nicely on 1st try reading 710, 720, 730, & 740ma.....add that all up and its exactly 2.9A....exact rating of the driver. Each string is running right around 36.1V give or take a tenth.
Couple observations of the driver....LED power and dimming wiring is 16 awg compared to the ELNs which are 22 I believe. Dimming is very very smooth and no dead spot before you get lights. In fact the dimmer won't turn them off.....not sure why but in the lowest setting my meter showed 0.04A which doesn't make sense and the LEDs are on very low.... I didn't think to switch it to the 200ma range at the time because I was going through each string. So the only way to turn off the HLG for now is remove main power. I'll have to take more readings with the dimmer all the way off and see if I can make any sense of it. But the dimming is extremely smooth.
Finally, the driver runs very cool compared to the ELNs I have. So far so good.
Kcress if you have any thoughts on the dimmer low setting let me know.
Looking for a 'quick connect' option for my build.
I will be wiring up 4 strings in parallel off a HLG-150 (times 2: 8 strings x 2 drivers), using 22 gauge wire. The drivers will be many feet away from the rig, which will be mounted in a custom canopy. I would like to be able to disconnect the rig form the drivers for easy removal from canopy. Was thinking of using 4 pin wire-to-wire connectors (times 2), one wire for each string in parallel. but am unaware of the quality of such items.
Are there any issues I should be concerned with by using these?
Are there other options out there? I think I saw a while back katchupoy using phone jacks for individual rails.
Can I get such connectors locally (e.g. Radio Shack, Home Depot, Lowe's), or is online best?
Thanks.
I will be wiring up 4 strings in parallel off a HLG-150 (times 2: 8 strings x 2 drivers), using 22 gauge wire. The drivers will be many feet away from the rig, which will be mounted in a custom canopy. I would like to be able to disconnect the rig form the drivers for easy removal from canopy. Was thinking of using 4 pin wire-to-wire connectors (times 2), one wire for each string in parallel. but am unaware of the quality of such items.
Are there any issues I should be concerned with by using these?
Are there other options out there? I think I saw a while back katchupoy using phone jacks for individual rails.
Can I get such connectors locally (e.g. Radio Shack, Home Depot, Lowe's), or is online best?
Thanks.
Last edited:
katchupoy
New member
I hate my phone jacks, not because of the jacks but because of the wires. I believe I used really old phone wirings thats why their wire does not solder well. As in it does not stick at all... No matter what I do...
I really like mic, or headphone cables or extensions so that you already have the plugs built it already... Just split it into two and hadwired the ends to each piece the jacks will be your disconnects.
and to make my arduino controller + LCD disconnects easy from the LED driver easily for service... I used RCA jacks.
and this.
TheFishMan65
New member
I don't know if those will work. But things to check
- Make sure the gauge is heavy enough.
- And since it is a long run you want a little extra.
- Make sure the gauge is heavy enough.
- And since it is a long run you want a little extra.
Thanks...will consider those.
Drivers will probably be no more than about 5-6 feet away from rig. I would think 22 gauge would be good enough...agree? I hope so... I already got a large order of it.
brassmonkyballs
BMB
How about Molex connectors....radio shack.
TheFishMan65
New member
From what I am finding on line 22 is OK, but 20 might have been better.
great suggestions...thanks!
Yeah... I went with 22 as is seemed to be on the thicker side of what was being suggested. Here are some quotes from somewhere on this thread (page 200???). Either way, like you said "22 is OK"...
To quote der_wille_zur_macht, "œWire gauge between LEDs should be 20 - 26 gauge, pretinned, with good insulation."
"for between the LEDs, something in the 22 - 24 gauge range is fine. Pretinned is best, and you want something with good insulation, i.e. not cheap speaker wire from Rat Shack where the insulation will melt/catch fire if it gets hot."
staggeringwade
New member
Hi guys,
Its been a while since I have visited the forum. I am happy to say that the DIY led light fixture is doing great as well as all of the reef inhabitants.
I just had something happen to the lights though-I'll explain.
I added another 24 leds -two 12 each kits from "rapid led.com" to my fixture. I'm using the dimmable meanwells for my RKE ALC.
Everything works fine, however I think that there is stray voltage coming from somewhere on the frame work of the fixture.
As an example if i touch the fixture with a damp hand and stick my other hand in the aquarium I get a little buzz :eek2:
Anyway, the Digital Aquatics SL1 modules ph probe goes nuts which is my biggest problem. I cannot calibrate it, it just drifts away in minutes.
I took the aluminum frame of the light fixture and grounded it to a wall outlet
and the SL1 ph reading says "error". If i disconnect the ground the SL1 ph reading comes back, but incorrect readings.
So I have to assume that maybe there is a short from an led grounding out on the heatsink somewhere? I did test every led to make sure there were no shorts with voltmeter, I can retest though.
Has anybody witnessed a short in a string of leds like this before?
I was curious to know if it was an actual short, would the string of leds not illuminate?
Wade
Its been a while since I have visited the forum. I am happy to say that the DIY led light fixture is doing great as well as all of the reef inhabitants.
I just had something happen to the lights though-I'll explain.
I added another 24 leds -two 12 each kits from "rapid led.com" to my fixture. I'm using the dimmable meanwells for my RKE ALC.
Everything works fine, however I think that there is stray voltage coming from somewhere on the frame work of the fixture.
As an example if i touch the fixture with a damp hand and stick my other hand in the aquarium I get a little buzz :eek2:
Anyway, the Digital Aquatics SL1 modules ph probe goes nuts which is my biggest problem. I cannot calibrate it, it just drifts away in minutes.
I took the aluminum frame of the light fixture and grounded it to a wall outlet
and the SL1 ph reading says "error". If i disconnect the ground the SL1 ph reading comes back, but incorrect readings.
So I have to assume that maybe there is a short from an led grounding out on the heatsink somewhere? I did test every led to make sure there were no shorts with voltmeter, I can retest though.
Has anybody witnessed a short in a string of leds like this before?
I was curious to know if it was an actual short, would the string of leds not illuminate?
Wade
brassmonkyballs
BMB
I assume its since you added the new ones? At any rate...check your solder joints and wire on the stars. If you got a little sloppy on one or stripped it a but long and its touching the side of the star you get a short to the heatsink. it doesn't take much. I always check every LED for path to the heatsink with continuity test/diode test (which lights the LED). If you can light the LED by testing between the heatsink and LED then thats a problem. I caught 2 just this weekend on a build I was working on.
TheFishMan65
New member
If you unplug the LEDs does the pH probe work. That would at least tell you that you are on the right track.
Many members have recommended mixing in neutral whites with the cool whites. If you start out with 60% royal blue and then divide the 40% white into 20% cool white and 20% neutral white over a large tank, at what point do you start to get a spot light effect of different whites compared to a blending of all the colors? Are there any recommendation on how far apart the different whites can be to blend colors instead of having seperate colors? I can see the blending of the different whites would work when all clustered together in one heatsink, but will it still work when attaching the leds to C channel over the entire length and width of the tank? I already have my royal blue leds and need to order the whites but wanted to address this issue to know whether I am ordering all cool whites or a combination of neutrals and cool. Any help would be appreciated. Due to hood size, the leds will be close to the water surface and will not be using lenses other than maybe the first row of leds (total of six rows with 24 leds per row) due to the depth of the tank (24") in the front of the tank.
TBR701
TBR701
vietcu
New member
Please help. I am working on my array tonight and had one string wired up, however when I turned it on. Only he first 7 Led lights up while the last 6 do not. What am I doing wrong here?
Using Meanwell 48D, and temporarily using a 9V walwart just so I can check that I am wiring everything correctly. The internal trimpot is turned all the way down, when I tried to increase it thinking it needed extra juice to light up the remaining 6 Led. But the first 7 would increase in power and nothing more. Help please.
Using Meanwell 48D, and temporarily using a 9V walwart just so I can check that I am wiring everything correctly. The internal trimpot is turned all the way down, when I tried to increase it thinking it needed extra juice to light up the remaining 6 Led. But the first 7 would increase in power and nothing more. Help please.
staggeringwade
New member
I unplugged the led lights and the ph probe still gives weird readings.
I just retested all of my leds with voltmeter and I'm stumped. I pulled one blue led out of the string that was seemingly causing all of the trouble.
If i test the led it seems fine-continuity test/diode test (which lights the LED) however when i place it on the heatsink the continuity alarm beeps, indicating a short. My soldering is clean with short wire ends.
Can the led be bad? I thought either they work or they don't (of course depends on operator error).
Can I run the string with only 11 leds until I purchase a new one. I'm running the 3 watt crees Q5 RB from rapid led with a meanwell Eln 60-48D @ .650 ma on a Digital Aquatics ALC.
Wade
vietcu
New member
Could not get in to edit my post, so had to post again. I found a little problem with my wiring while doing the AA battery test. Seems that I have some stray voltage going aruond, wondering how I can fix this. When I touch the positive wire of the AA battery to the positive position on Led #6, and the negative wire of the AA battery to the heatsink, led #7 comes on. And seems to affect a few others from #7 on, but I didn't see which wire was touching what to be absolutely sure, but similiar to the previous explanation. Do I need to re solder? Some help please as this is my first attempt at doing this.
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