# How Many 3W LEDs for low tech 55?



## ChrisX (May 28, 2017)

Hello,

I am upgrading the Aqueon Deluxe Flourescent Hoods that came with my new 50gallon (48" x 12" x 19") tank. The plan is to remove the flourescent internals and build the heat sink and fans into the enclosures. The led driver will be attached to the back of the housing.

I need guidance in estimating how many 3W leds I will need for this low tech planted tank. 

The plan is to move the plants from my 29 into the 50. It has Amazon Swords (have grown to about 15"), Hygrophilia, Lugwigia Repens, and Creeping Jenny, all of which were doing well until the DIY Led strip lights started to burn out and yellow. Now there is alot of green algae and stem plants arent doing great anymore. Tank is sand over soil, Co2 Booster, root tabs, Leaf Zone.

I think these are easy medium light plants and I don't plan to do anything more difficult. The growth was steady without CO2, so I'm looking for light that is in the sweet spot -- good enough to grow, but doesnt need CO2. Nothing against CO2 setups and I will do one eventually, just not yet.

My 29 is/was lit with roughly 1.5 ledmo 6000K 3650 strips..roughly 90 watts. Was lit pretty well.


Guessing that I will need 30x 3W Leds. Mostly white with some blue and red. Opinions?


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## jeffkrol (Jun 5, 2013)

largest dim. is usually 1st. 
did you mean 5630's?

Using smd strips your wattage is usually system watts and not exactly comparable to 3w constant currrent.

Anyways..any game plan for automation?


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## ChrisX (May 28, 2017)

Yeah, opps type. They are 5630s.

I was wondering about automation. If I get drivers with a dimmable input, then theoretically there is probably some controller that would allow me to automate the cycle. Is that really necessary? I use a wall timer with two on periods and a siesta. I have an RGB strip on separate power that I can add for color enhancement or moonlight.

So, how many 3W LEDS for a 55g? I'm thinking 32. Should I go all 6500K, or mix in some red/blue? I know I can get fancy with multiple drivers, but this is just low tech.

Bump: Also, is there a way to get rid of ad streaming on this site? It really messes up the forum functions; keystrokes are lagging and missed. I cant see myself using this site much because of all the lagging and blocking from the ads.


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## jeffkrol (Jun 5, 2013)

I happen to think dimming is a necessity...
Esp if you use 32 3W emitters on a 55gal. 

automation (ramp up/down multi-channel) isn't but it can be relatively cheap w/ some solder-equity 

There are numerous ways to approach this and tech changes all the time.
suggest looking at these constant current Bridgelux EB strips for a retrofit..
11", 22" or 44" 1" wide..
Should be able to pack at least 3 per "bay" @ 22".. You need to check your room. 15W 2400 lumens per 22" strip @ 700mA

http://www.plantedtank.net/forums/2...-leds-prev-vero18-*updated-2017-01-18*-9.html
Easy to get a 2 channel design (cool white/warm white)

Short list:
Strips
Power supply (24V 6A for 6 EB strips)
LED drivers w/ 5V pwm (3 minimum @ @ $8 each)
dimmers or programmer ($9 to $40 w/ some solder skill to mod off the shelf parts. See http://www.plantedtank.net/forums/20-diy/980633-how-use-tc-420-control-ldd-drivers.html

As to "wattage" well that is a bit tricky due to efficiencies/in-efficiencies of LED brands/styles
Personally anything over 30W needs some "control".. 
90W can translate into the old 3W/gallon thinking..but depends on efficiency of emitters..


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## ChrisX (May 28, 2017)

Thanks. As far as dimming, I was planning a really low tech solution which is to put a grate between the lights and glass. 

For instance bug screening or chicken wire. AFAIK that would reduce intensity by some %, and it could be adjusted based upon quantity/type of material. I could simply put thin strips of tape across glass. Or I could remove leds if the driver isn't too large.

This way if I ever get CO2, I can just remove the filter.

Ive decided to use a mix of cool white and warm white. Can someone recommend a good ratio of cool to warm?

I'm thinking 70% cool, 30% warm.



jeffkrol said:


> I happen to think dimming is a necessity...
> Esp if you use 32 3W emitters on a 55gal.
> 
> automation (ramp up/down multi-channel) isn't but it can be relatively cheap w/ some solder-equity
> ...


Reading this again, took some time to sink in.

I was leaning towards AC input driver so I can use the switch/plug and internals already built into hood. Just a very basic on/off operation. Color balance made based on LED ratios, not using separate banks.

Leaning away from DC because would require separate power supply as well a driver, (and more hacking of the encasement) but I know it is much more functional.

I already have 2x 60W (12V) unregulated power supplies. If I could reuse these with CCD, I would be interested, but I would need to know how to wire the 3K LEDS. I think I would need a CCD that could raise the voltage, because 12V at a fixed 600mA wouldnt light many leds.

BTW, there are 2x 22" light bars being retrofit. So I was planning on a single channel for each bar with a 70/30 mix of cool white / warm white each. What kind of drivers would I need to reuse the 60Watt power bricks I own?


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## jeffkrol (Jun 5, 2013)

ChrisX said:


> Ive decided to use a mix of cool white and warm white. Can someone recommend a good ratio of cool to warm?
> 
> I'm thinking 70% cool, 30% warm.


Fairly standard, you can play a bit w/ this:
SPECTRA



ChrisX said:


> Reading this again, took some time to sink in.
> 
> I was leaning towards AC input driver so I can use the switch/plug and internals already built into hood. Just a very basic on/off operation. Color balance made based on LED ratios, not using separate banks.
> 
> ...


Generally switching power supplies are used..Bit less critical w/ constant current drivers but a bit necessary w/ things like strips that run constant voltage.
Voltage variations will run havoc on output and longevity..
LED series parallel array wizard

this will give you an idea what you can or cannot do ..
It's for designing constant voltage strips using resistors as "current regulators"..
3W diode forward voltage varies from 2-4v.. Using 3.7 for cheapp 3w diodes will keep you in the ballpark.
Note voltage changes w/ current fed.. well the higher the voltage the higher the current the LED will use..
too much voltage and it goes into thermal runaway and frys out..

constant current or constant voltage your V9f) is still key..









your ps are capable of 5A..


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## ChrisX (May 28, 2017)

jeffkrol said:


> Generally switching power supplies are used..Bit less critical w/ constant current drivers but a bit necessary w/ things like strips that run constant voltage.
> Voltage variations will run havoc on output and longevity..
> LED series parallel array wizard
> 
> ...


So cool, thanks so much! I suspected there was a series/parallel organization that would let me use the 12V supplies.

Just so I'm clear, in this configuration, would I need a constant current driver or could I connect to power directly?

If this works directly from switching power supply (converted computer PS), it unlocks potential for some really inexpensive (and scaleable) arrays. But would they also work from my bricks?

BTW, I believe the quality of my LED strips (first endeavor in DIY lighting) degraded because of unregulated supplies and poor power. If I am to understand, if I were to have used a switching supply with those strips, they would have lasted much longer?


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## jeffkrol (Jun 5, 2013)

ChrisX said:


> So cool, thanks so much! I suspected there was a series/parallel organization that would let me use the 12V supplies.
> 
> Just so I'm clear, in this configuration, would I need a constant current driver or could I connect to power directly?
> 
> If this works directly from switching power supply (converted computer PS), it unlocks potential for some really inexpensive (and scaleable) arrays. But would they also work from my bricks?


As long as you add the resistors yea it works for larger diodes/arrays..
not as efficient as constant current.. See waste heat on the resistors.
substituting Meanwell LDDs for a resistor adds $7/ 3 diodes at 12V.. 




ChrisX said:


> BTW, I believe the quality of my LED strips (first endeavor in DIY lighting) degraded because of unregulated supplies and poor power. If I am to understand, if I were to have used a switching supply with those strips, they would have lasted much longer?


Possibly.. They also have poor thermal management and heat is the enemy


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## ChrisX (May 28, 2017)

jeffkrol said:


> As long as you add the resistors yea it works for larger diodes/arrays..
> not as efficient as constant current.. See waste heat on the resistors.
> substituting Meanwell LDDs for a resistor adds $7/ 3 diodes at 12V..


Given the above diagram, would it be possible to use my 60W power brick and a single LDD? How would it be wired?

It sounds like what you are saying is that each resistor would be replaced with a LDD, which would not be cost effective. Either I would need a higher Voltage supply, or multiple LDDs. (?)

What would be the effect of just powering that circuit with the 60W brick? It is rated at 12V (I would need to check actual voltage), but I suspect V drops very significantly as current draw rises, so as I add more LEDs, each one would have less intensity. I don't want that!

Alternatively, I could convert an old 400W computer power supply and power that circuit directly.

This is a budget build (for now). I could geek out (and may later), but I just want a basic low/medium light setup for a low tech 50g.

BTW, the resistors in that diagram, what power rating would they need?


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## jeffkrol (Jun 5, 2013)

ChrisX said:


> Given the above diagram, would it be possible to use my 60W power brick and a single LDD? How would it be wired?
> 
> It sounds like what you are saying is that each resistor would be replaced with a LDD, which would not be cost effective. Either I would need a higher Voltage supply, or multiple LDDs. (?)


power supply to driver ..driver out to LED's. 
Voltage of the power supply determines # of diodes you can drive.. Add V(f) up..
Also note LDD's require a voltage differential of 2-3V...
In other words if you have a 12V power supply and run LDD's you effectively only can output 10V.. 
I really don't recommend under 24V ps for Ldd's that is cost ineffective.. 24-2= 22
22/3.7 = 5 and possibly 6 (depends on the diodes and drive current) in series is more cost effective.. 


ChrisX said:


> What would be the effect of just powering that circuit with the 60W brick? It is rated at 12V (I would need to check actual voltage), but I suspect V drops very significantly as current draw rises, so as I add more LEDs, each one would have less intensity. I don't want that!
> 
> Alternatively, I could convert an old 400W computer power supply and power that circuit directly.
> 
> ...


resistors would need to be rated at 1W or better..All data is listed..
Calculator seems to assume 2x actual or better so 2W is minimum.
computer power supply could probably run 30 3w diodes 
At say 500mA you would have an array of 3 in series x 10 rows.
Each row terminated w/ a 1W resistor @ 1.8Ohms..
https://www.amazon.com/1-8-Ohm-Flameproof-Resistor-Pcs/dp/B008EM16D6

all are estimates
and you need to be aware that you can't mix V(f)'s. All diodes should have roughly the same forward voltage..

so generally no red diodes allowed ..  though if you wanted some red you could use "full spectrum" 3w diodes which are really blue w/ heavy red emitting phosphors added.. Overall color is magenta..


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## ChrisX (May 28, 2017)

My concern about using an array with a 12V supply: What if one of the LEDs burns out? That could cause failure of the entire array. 

The obvious benefit of using constant current; everything can be wired in series and if one burns out, it doesnt affect the others.

Here is another option, a Voltage booster with trimpot adjustment.
https://www.amazon.com/GERI-Constan...&sr=8-12&keywords=LED+driver+constant+voltage

I could use this to create a constant (15V)voltage and use my power bricks. It would also allow me to adjust intensity with trimpot. 

Tell me, if one of the LEDs burns out in constant voltage array, will the whole circuit fry? If so, I will go with a constant current setup.





*Seriously, is there a way to disable the streaming ads on this site? I can barely type because of interrupts. Site is constantly reloading/blinking and blocking user input.*

jeffkrol,

Thanks for your help. I decided to "keep it simple" and ordered a package of Ebay 3W LEDs and AC input CCDs, which I will retrofit into the flourescent hoods. The LEDS will be in a 70/30 ratio of cool/warm white, and the CCDs can handle somewhere between 8 and 16 LEDS, so I will control light intensity by the number of LEDS installed. Light cycle will be handled by external timer and supplemented with led strips I already have.

Now, I need to figure out a way to have small DC fans wired into circuit for cooling. Any suggestions?


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## jeffkrol (Jun 5, 2013)

> My concern about using an array with a 12V supply: What if one of the LEDs burns out? That could cause failure of the entire array.


no, just the triplet row.. all other 9 parallel channels will run fine..

Where one runs into problems is if you series/parallel off one constant current driver..
Say you have 2 parallel branches running off a 1A constant current driver..
Effectively each branch "sees" 500mA.
If one branch goes "open" all 1A will now go to the remaining branch.. 
So normally 1 driver-1 series string prevails with constant current..

Series/parallel constant voltage doesn't have that issue..


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## ChrisX (May 28, 2017)

jeffkrol said:


> no, just the triplet row.. all other 9 parallel channels will run fine..
> 
> Where one runs into problems is if you series/parallel off one constant current driver..
> Say you have 2 parallel branches running off a 1A constant current driver..
> ...


It turns out that the parallel resistors cost about the same as the constant current driver. While that could be a great strategy for someone who already has the power supplies and resistors, its not cost effective and adds to the complexity of the circuit. (And as mentioned, you lose one, you lose the row.) Also, my supplies are not regulated and would benefit from the Voltage regulator, which again adds to the cost.

I would have liked ability to dim certain LEDS, but thats getting fancy for little benefit at this point. With the CCD I can just add/remove LEDs and change ratios of whites. Will be fine for my low tech build.

Thanks again! I'm sure I will be back with updates/questions sometime in the next week as I retrofit my lights. This build will help prove the cost effectiveness/reliability of budget ebay builds. (I may have to start over.. but this is only $40 in components and should give between 50-100 Watts total, efficiency unknown, but I'm gambling it will be enough.)


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## ChrisX (May 28, 2017)

I got my LED shipment. They are "epistar" brand. I'm sure they are not in the same ballpark as cree, but I'm hopeful. Using inexpensive LEDs will let me experiement with different colors.

The specs are as listed:










The drivers were also purchased from this seller, they say they are 600 mA constant current, 60Watt. Out Voltage: 54-105V It says 18-30 x 2(3)w. That is kinda vague. 

If the drivers forward voltage is 3.2-3.4V @ 700 mA, what is the forward voltage at 600? (Is it * 6/7) Are these effectively 2.*V at 600?

I am trying to decide how many or how few I can run from each driver.


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## Kampo (Nov 3, 2015)

at 600ma your going to be arround 3.3 volts prolly so the listed number of diodes for the voltages your driver supports is correct. anywhere from 18-30 will be fine.


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## jeffkrol (Jun 5, 2013)

> 3.2-3.4V @ 700 mA, what is the forward voltage at 600? (Is it * 6/7)


no, it is logarithmic, or at the very lest a steep slope..

could be like [email protected] 600mA


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## ChrisX (May 28, 2017)

Question about heat sink:

I know most people over engineer the heat sink... 

These are going into 2x Aqueon Flourescent light bars.. The dimensions roughly 4x4x22". 

The plan was to use 1" Aluminum "L" bar from Home Depot. Cut four bars at 22" each ,2 bars in each hood. On each bar, 10 LEDS spaced at 2 inches. The light bars would have enough room for a third (maybe fourth) 1" bar each.

At the start, there will be 20 leds each side, 10 per bar. Will this spacing create noticable disco effect? Should I stagger the LEDS?

[* * * * * * * * * * ]
[ * * * * * * * * * *]

Would it be sufficient to use 1/16" bar, or should I use 1/8". IOW, I have no idea the scale of heat generated by these things.

If testing shows that the light bars get toasty, I will install a small fan and vent holes in each.


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## ChrisX (May 28, 2017)

Also, how bright do you suspect this will be?

I was thinking about this Beamswork, that has 63 x 1W over 48". 63 Watts.
https://www.amazon.com/dp/B01FVNPZN2/_encoding=UTF8?coliid=I1EDT8Q35ATYFB&colid=IQK8HGIFWXGK

In comparison, mine will have 40 x3W = 120 Watts.

Do you think it will be roughly 2x as bright?


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## jeffkrol (Jun 5, 2013)

ChrisX said:


> Question about heat sink:
> 
> I know most people over engineer the heat sink...
> 
> ...


since it is enclosed and a fairly high density (21/2" on center is relatively standard) suggest using "proper" heatsink material..
Exponentially increases surface in roughly the same l/r b/f footprint.
Price will be close to the same..
1.83" is "best" but 1" is fine..

$28 for 4 22" 1" pieces
(base is 1/10" thick..)
$75 4 21" 1.8" pieces

Prices inc. s/h...

note 3W is "theoretical" output..Think of it as max. drive current..
3.4x .6 = 2.04W/diode...
882mA will get you 3W....
also note electrical characteristics can VARY widely..


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## ChrisX (May 28, 2017)

No message.


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## jeffkrol (Jun 5, 2013)

Opps, forgot the link..

HeatsinkUSA


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## ChrisX (May 28, 2017)

jeffkrol said:


> Opps, forgot the link..
> 
> HeatsinkUSA


So I don't reinvent the wheel, what is the best placement strategy? I was thinking about getting a single 2.45" heatsink for each hood. How would you place 20 leds on a 22" bar?

[
[ ******************** ]
[

[* * * * * * * * * *]
[
[* * * * * * * * * *]

[* * * * * * * * * * ]
[
[ * * * * * * * * * *]

Something you said lead me to believe that if the leds are spaced 2" apart, I might get a spotlight effect.


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## jeffkrol (Jun 5, 2013)

Relatively to scale...


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## ChrisX (May 28, 2017)

Are they intentionally inexact?


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## jeffkrol (Jun 5, 2013)

ChrisX said:


> Are they intentionally inexact?


LOL.. No.. just in a hurry..


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## ChrisX (May 28, 2017)

Hi,
I have reconsidered the drivers I am going to use. The ones that came with the LEDS are 60W and are not dimmable. These are the new ones I consider:

IDLC Series Mean Well 45W CC LED Driver with 2 in 1 dimming

These meanwell 45W drivers are dimmable w/ AC input. I want AC input because I am retrofitting flour hoods.

Regarding dimmable input, it is 0-10V and PWM. Would the PWM dimmable allow me to use with a light controller?

At 45W 700mA, how many 3W leds can I run from one? (I will have one for each hood)

The other ones are 60W 600mA and could run 18-30 each.


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## jeffkrol (Jun 5, 2013)

you have 38-64V available..
Keep in mind (and if I understand this correctly) at 120V your output is de-rated to 80%..
560mA...not 700mA (35.84W max)

voltage is the only real consideration in #'s per string..

Add up the strings V(f) at the drive current and stay within 38-64V
i.e if V(f) is 3.4V at 560mA then you can power (at full current) min. of 12 up to 18

as to control 0-10V or 10V PWM controllers are available..
Problem is there are, to my knowledge, none cheap (Apex, Full blown Bluefish, old BML Sonular (cheap but unavailable? 3ch I believe))..well at least w/out parts or modifications.
https://www.amazon.com/dp/B06XB6J4F...t=&hvlocphy=9019191&hvtargid=pla-312766942497
Needs PWM input and a separate power supply
converting cheap 5V PWM controllers to 0-10V requires added "parts"..but still is cheaper than an Apex of bluefish..

SIDE NOTE: It "may" be possible to use the Kessil to control 2 drivers @ only $100
Just a "maybe" though..
https://www.saltwateraquarium.com/s...tm_source=bc&gclid=CLq80cOfwNQCFQmFaQod-GwH7A

note also that since this driver does seem to "throttle" current there will be a bit more color shift in white led's at low currents..
PWM drivers just go from full on to full off "mimicking" a current reduction. 
Just a "is" not really a problem..


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## ChrisX (May 28, 2017)

Sounds like a hassle. I was hoping to control dimming with a pot. Can I use a pot as a dimmer?

Bump: The problem with the drivers I ordered is that I have two that power 18-30 each.

That means, the least I can have in one light bar is x18. That is x36 both sides and I'm betting that is already very bright.


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## jeffkrol (Jun 5, 2013)

ChrisX said:


> Sounds like a hassle. I was hoping to control dimming with a pot. Can I use a pot as a dimmer?
> 
> Bump: The problem with the drivers I ordered is that I have two that power 18-30 each.
> 
> That means, the least I can have in one light bar is x18. That is x36 both sides and I'm betting that is already very bright.


well pot and 10v DC ps.... 
simple enough..

you could get one of these and just hook a 10v wall wart to it..
Will give you 10v PWM on the output..
PWM Dimming Controller For LED Lights or Ribbon 12 Volt 8 AmpAdjustable Brightness Light Switch Dimmer Controller DC12V 8A 96W for Led Strip Light 5514243 2017 ? $3.99

Ones I played w/ work fine at down to 9v even though listed 12-24V no guarantee though..
Or $11.99 on the world marketplace..


*Details about PWM 0-10V 1-10V Dimmer AC110V 220V LED Controller Potentiometer for LED Lamp*


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## ChrisX (May 28, 2017)

jeffkrol said:


> Ones I played w/ work fine at down to 9v even though listed 12-24V no guarantee though..
> Or $11.99 on the world marketplace..
> 
> 
> *Details about PWM 0-10V 1-10V Dimmer AC110V 220V LED Controller Potentiometer for LED Lamp*


Do you mean they worked with a 9V supply? Or they could be dimmed down to 9V?



Perhaps you can recommend a better dimmable driver? Needs to drive 20 ish 3W drivers, cost effective and simple dimming, preferably AC input.


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## jeffkrol (Jun 5, 2013)

Put it this way.. They powered up fine at 9V..since I wasn't using the output taps it is assumed they are at 9v as well..
If you power it w/ 12v you get 12v out.. that I know..There is nothing that would create a voltage loss (well much) in the output circuitry since it is a simple MOSFET "switch"..

As listed above the $12 dimmer off eek bay runs off line voltage and outputs 10v dimmable w/ pot..
Really cheap (price and build)and of course china direct

all you need is a 10V DC wall wart (check output voltage though.) and a 10K pot
http://www.plantedtank.net/forums/1...ing-dimmable-drivers-40w-led-floodlights.html


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## ChrisX (May 28, 2017)

Thanks! That explains it very well. Just need a 10V supply and a 10K pot.


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## ChrisX (May 28, 2017)

Just wanted to give an update on this project. I completed the first light bar and will soon solder the LEDs on the next one.

This was built into and Aqueon Flouroscent light bar, maintaining the stock appearance and on/off switch operation.

Each hood has 20x 3W leds, 10 on each bar. 15x Cool White (6-6.5K), 5x Warm White (3-3.5K). They are mounted on aluminum L-shaped 1" x 1/8" thick bar. I went with aluminum stock from HD because for 2/3rds the cost, get more mass, but (marginally?) less surface area. Five minutes away. 

I tapped the aluminum side brackets so the internals can be quickly removed with two screws on the back. The driver is zip tied behind the bar and cant be seen from the front.

These are the inexpensive ebah Epistar brand leds and CCDs from the same seller. You can see from the pic how I alternated between colors. I used 14ga solid copper wire. (would choose stranded next time.) It took about half a tube of Arctic Silver heatsink compound I had leftover from a computer build. 

First thought.. it's insanely bright! The Epistar leds may not be Cree's, but they are .50c/ea and together are as bright as the sun. Efficiency not a concern, longevity is tbd. My guess is that these provide 2x the light as something like a 48" Beamswork bar. Would need two full bars to equal these. Each driver is 60Watts, so 120Watts capacity. I can add 10 more leds per side if I need more light, but I don't think I will. I may need to reduce the lighting..

I am doing a burn-in test atm. Originally left unattended on the bench for 30 min, the heat sinks got quite toasty. Able to touch, but uncomfortable.. probably 120* F. However, setup with a fan blowing on them, the heatsinks stay cool to the touch. 

(continued)


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## ChrisX (May 28, 2017)

Total cost about $80.

Leds and drivers $40
Heatsink aluminum(96" L-bar & 48" flat for side supports) $30
Arctic Silver $5 (had)
Fasteners $5
Epoxy $5
Wire $1

Advantages: 

Probably about 1/3rd cost of equivalent PAR from commercial offering.

Custom pick colors and modify array depending on what look I want. I went with a 75/25 mix of cold and warm white which I think will be good to start.

Can add another 1" bar to each hood, add more leds, separate drivers, etc. Highly customizable.

Looks stock, reuses switch and plug.

If a commercial product fails, SOL. If this fails, I can replace components.


Disadvantages:

Build time 6 hours first bar, 3 hours second bar.

These AC drivers are not dimmable. 


Improvements:

Heatsink design. An actual heatsink might provide much better performance, although fan keeps them cool. I will need to do more testing and decide if they need a fan and ventilation. 

These may turn out to be too bright. It may be sufficient to use only one driver to light 10x leds in each hood, in which case I bought twice as much as I needed (although that would solve any heat issues.)

There may be a better way to attach LEDs than epoxy.

Drivers are 60W each, 30W drivers may have been sufficient.

Next interation of this system will have dimmable drivers, but so far am happy with the build.

Bump: More pics:


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## jeffkrol (Jun 5, 2013)

Nice work..


couple of things:


> There may be a better way to attach LEDs than epoxy.


Things like heatsink plaster work well (thermally conductive silicone basically)
For these cheaper diodes expensive thermal epoxy is pretty irrelevant..
Small warning.. If the epoxy has poor heat conductance those diodes will not last too long..but I take it you thermal-ed the center.. so may be no problem..
Other way is drill/tap/screw..



> Drivers are 60W each, 30W drivers may have been sufficient.


Max wattage only effects the # of diodes..
Depending on the cc driver a 30W or 60W would both run ..say 2 3W LED's..so 6W regardless of driver rating.
Only need to worry about minimum rated load..

At $1/each there are some Luxeon Rebels on d bay that have way out-performed many of the epi's I've used..


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## ChrisX (May 28, 2017)

They are actually $5 for 10x, so 50 cents ea. This is my first build, im sure i will try other components in future.

I used arctic silver cpu paste on each led base. The edges were epoxied down. The epoxy is rated at like 300 degrees. I dislike the mess, but drilling tapping attaching would add alot of time and money to project.


I held the bar over my quarantine 29g, and i really like the look. I think the balance is good. 

When both bars are complete i may rewire each side to run 14 leds, all powered by one driver. Sadly, the minimum voltage requires 18 leds. Its not too bright for high tech, but im not running co2 yet. 

Its surprising how cool the heatsinks are with a little breeze, but how toasty they get without any. I estimate 120 deg, can hold hand on it uncomfortably. If the operating range is up to (say) 200 deg, maybe i dont have to do anything more. I could also increase surface area by slotting the upright part of bar.


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## jeffkrol (Jun 5, 2013)

110-120F is usually tolerable for all but the cheapest diodes.....(not price, but manuf.)

If necessary.. you can always "downgrade" the driver..don't need to change string lengths..
What mA did you pick?

Get a LUX app for your phone and measure LUX at say 12"


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## ChrisX (May 28, 2017)

Led supply recommends 3" surface area per watt. The bars are 22"..so almost 90 sq in for 30 watts. Should be enough, but when set on top of glass they might get hotter. I will experiment, but i think this should be ok. Will take temp and decide. 

I will measure lux tomorrow. Is there something i can use as a reference to tell approx how bright it is?

Bump: The drivers run at 600 mA.

Bump: Also, slotting the upright would add significantly to surface area. Each cut cut would add .25 sq in surface area. Can make eight cuts per inch... x22..would add another 44 sq in surface area.


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## ChrisX (May 28, 2017)

Just another update....

One (two) of the leds failed on the first bar. The problem is that I used 14g solid copper wire. The PCB bases have a very thin contact metal which can become detached from the pcb. The solid copper wires exert too much force on these squares. (I would press down on the contact and get better connection, but resoldering did not fix this "cold" connection. Some of the squares completely separated from the pcb.) Also the thicker, solid core wire is harder to work with.

I'm doing the second one with 18g stranded and it is going much better.


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## jeffkrol (Jun 5, 2013)

most common "conversion" of Lux to PPFD:


> divide the number of lux by 67.3


1000Lux/67.3= 14.86PAR/ 1000Lux
Still trying to figure this one out.. 
Photosynthetic Photon Flux Density (PPFD) Concepts


> kilolux to PPFD in μmol/s-m2:


Divide Lux by 1000 then multiply by 14.6 (@5000K)

1000/1000= 1x 14.6=14.6

As to wiring.. diode/diode connections can use much thinner wiring..
Driver to string power delivery needs a bit beefier.. 
Have switched all to 20ga stranded for overkill really.
Can get cheap spools off the bay..

Yea solid is a PIA in large sizes.. Used 18ga solid in early builds.. too stiff.

you can measure the voltage across the +/- at the driver.. Multiply by .6 to get "real" watts across the string..approx..


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## ChrisX (May 28, 2017)

I finished wiring the second light bar and I cannot recommend these leds. The problem seems to be that the contact between led and pcb is compromised. Slightly moving a wire (soldered to the pcb) can make a light go on/off. There is a short somewhere inside the PCB, although it will pass current through to the next.

So far there are at least four that are bad. I may be able to bypass the pcb and solder directly to the led.

BTW, I am fetching some sunglasses; I'm going blind testing these.


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## ChrisX (May 28, 2017)

Phone light meters are junk. Two different ones different readings. Getting closer, lux goes down.


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## jeffkrol (Jun 5, 2013)

ChrisX said:


> Phone light meters are junk. Two different ones different readings. Getting closer, lux goes down.


Depending where you are that is not unusual as you go between the cones of the emitters..
The idea is to ballpark it..

assumption is the software just uses the output of the green filtered pixels in the Bayer array..
Maybe a bit of weighting for the r/b pixels..

Yea.. Best to give up on the phone thing.. didn't realize how bad the error was..

https://www.dial.de/en/blog/article...artphones-suitable-for-measuring-illuminance/

my bad.. Corrected..


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## ChrisX (May 28, 2017)

jeffkrol said:


> Depending where you are that is not unusual as you go between the cones of the emitters..
> The idea is to ballpark it..
> 
> assumption is the software just uses the output of the green filtered pixels in the Bayer array..
> ...


Not only are they inaccurate, they need to be calibrated.

I have decided to rewire both led arrays. The PCB contacts are junk, I have solved the issues by wiring directly to the leds.

Temperature seems to have stabilized at 127* over 2 hours (but the bottom is open, need to test it on glass lid). This is adequate I suppose, but slotting the heatsinks would give more headroom.

Overall, happy with the project, but would have chosen better brand leds, or just wired directly to the leds first time. Hopefully this will help someone.

This is really bright, thats all I can say for now. I'm sure it will have no problem growing plants.


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## ChrisX (May 28, 2017)

I mounted one of the bars on the tank. Looks great! Nice shimmer effect, brings out the colors of my fish. This looks really "pro" to my eyes. Tank is full of tannens from dirt substrate, but light cut through very well. This much light makes a case for keeping the tannens.

I was afraid the fish would not like it, but they congregated in the "sunlight".

Temp of heatsink (enclosed) after an hour was 170* (77*C). This is less than a typical high wattage incandescent, so I dont think it is a safety hazard. According to Cree, their leds are tested from range of 70-105* (but that is at the intersection, it might be hotter there.) So this temp does not seem unrealistic. 

OTH, I will probably add some ventilation fans. I can at least vent the enclosure, not sure about directing air over the heat sinks. I like the fully enclosed look where light does not spill out like commercial bars, but obviously ventilation becomes a concern. This is probably why most solutions are open air.



http://www.cree.com/led-components/media/documents/LM80_Results.pdf

The plan is to source some small fans to ventilate the enclosures. I wonder if I can find some tiny transformers to run the fans?

Bump: I'm thinking of adding one of these to each hood:

https://www.amazon.com/Brushless-Fugetek-HT-07530D12-75x75x30mm-Computer/dp/B00B2ARV22/ref=sr_1_17?s=pc&ie=UTF8&qid=1497897595&sr=1-17&keywords=computer+fan#Ask

It runs at 12V. Do you know how I would use a potentiometer to lower the voltage so I could control the speed. 

I imagine I would need a pot and a resistor. What sizes?


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## jeffkrol (Jun 5, 2013)

pot is a resistor..sort of. Rheostat is the correct term I guess



> just explained why my 2W, 25 Ohm rheostats work just fine with my 120mm fans. BTW, I bought the rheostats at the Crack Shack.


Wattage depends on voltage drop which depends on resistance..


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## ChrisX (May 28, 2017)

Thanks. I ordered some 12v 50mm fans from Amazon for $5. 

This has become quite the entertaining project.


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## ChrisX (May 28, 2017)

I have had so many problems with these individual leds, I'm going to contact the seller for a refund.

The cheap ebay leds must have been from the failure bin, which means that some % of parts in each section did not pass.

The main problem is that the pcbs are not well connected to the leds. Some were intermittent from the start, others became defective after a short burn in.

One of the leds is shorted to ground and doesnt light at all.

I have been doing wiring projects and soldering for 30 years; I'm now convinced this is not user error.

Should have picked a more reputable part.

Ebay leds, don't do it!


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## jeffkrol (Jun 5, 2013)

ChrisX said:


> I have had so many problems with these individual leds, I'm going to contact the seller for a refund.
> 
> The cheap ebay leds must have been from the failure bin, which means that some % of parts in each section did not pass.
> 
> ...


like I mentioned earlier.. Luxeon Rebels are cost effective and stable and on the bay..AFAICT from a few builds..
biggest problem I've had is w/ low K "epistar"...

IF you go w/ "branded" LED's suggest some "pucks".. $/W is fairly equivalent..Like w/ Bridgelux Vero Decor.. 

$13/ 36W..
https://www.digikey.com/product-det...VM-14-56-95-36-AC00-F2-2/1214-1267-ND/5041238


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## ChrisX (May 28, 2017)

Good info.

I am really enjoying the shimmer effect I get from the LED bars. Looks like a swimming pool with water movement from bubbler. I wonder if the puck would be the same? My thinking is that it would not be as evenly distributed.

I asked ebay seller for refund or replace.


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## ChrisX (May 28, 2017)

I added a small 50mm fan to each hood. To run the fan, I modified a small unused 12v transformer so it could be mounted to the back of the bar. This could be used to power dimming and automation in the future.

These fans move 9cfm and are probably moving more than enough air. The bars stay cool to the touch with this level of circulation. Prior to adding the fans, the heatsinks were reading 170* after an hour of continuous operation. This may have been acceptable, but I wouldnt be able to add any more leds if desired.

This design was chosen to retain a stock look and block escaping light. (I dislike the amount of light that escapes from hanging and suspended fixtures.

Unfortunately, they are not quiet. They sound like running an overhead projector. Next step is to reduce the voltage to the fans so they are quieter.


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## ChrisX (May 28, 2017)

I'm pretty sure this is "high light". I have a few stems of Giant Hygro growing, and the new leaves at the top have a pinkish hue. 

I'm going to rewire the lights so there are only 10-15 per side, not 20.


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## The Dude1 (Jun 17, 2016)

This is a fantastic thread. I'm going to look into building a setup to mount in the canopy for my lab 150. That would free up the 2 LED fixtures I have in there and give my higher light when I get to that point.


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## ChrisX (May 28, 2017)

The Dude1 said:


> This is a fantastic thread. I'm going to look into building a setup to mount in the canopy for my lab 150. That would free up the 2 LED fixtures I have in there and give my higher light when I get to that point.



I would definitely do this again, hopefully you can learn something from this. 

If you are mounting this in a large canopy, you probably wont need fans, just size the heat sinks a little bigger.

I did it on a budget, but for a little bit more, you can get dimmable drivers. Jeff linked the post that shows how to do that.

40x leds for a 48" tank I believe is in the "high light" category. I am experimenting with putting tape on the glass to block light to the tank, later I will probably bypass some of the leds.


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## ChrisX (May 28, 2017)

The seller agreed to send me some replacement leds. I also ordered some "natural light" 4-4.5K. It may be all the tannins, but the 3-3.5K "warm" white makes everything look too yellow. 

I think mostly 6K with a small number of 4-4.5K will look best. Has anyone tried any of the 10K cold white leds in a planted? I have reasoned that these have lower par.

Otherwise, I've been pretty happy with the project. I currently have the glass taped under half the leds. Only 20x 3w leds over 48" looks about as bright as (say) a Beamswork 48".


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## ChrisX (May 28, 2017)

I'm going to start experimenting with different temp leds.

Each side currently has 15x 6-6.5k (cool white) and 5x 3-3.5k (warm white). While the tank is very bright, it has a bit yellowish look.

I also received some 4-4.5K (natural white) lights. I was going to replace the warm white with these, but would it be better to keep some of the warm white to retain their color?

I notice that most of the commercial led bars have predominantly cold white 6k+ and a token amount of blue, sometimes some red. Is it worth it to experiement with colors, or should I focus on getting the white balance correct?

IOW, I see some amazing dutch tanks with what appears to be cool/cold white spotlights. Not sure if I should order colred ones.


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## ChrisX (May 28, 2017)

V2 of this light is coming soon....


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## ChrisX (May 28, 2017)

Increased surface area of heatsinks by 40%...


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## ChrisX (May 28, 2017)

This version of the light runs the driver at full capacity, with 30x 3w leds.

After running the light bars for a week, I found that with the fan installed, the heat sinks never got more than "warm". < 100*. This meant there was some headroom.

Since I had extra leds, I decided to reposition them with 15x per bar. This is the maximum these drivers can support.

To handle the additional heat, I slotted the upright of each heatsink to increase surface area by about 40%. 

The epoxy is curing, but when I rewire them, they will be in three banks. I will be able to run the light with 18, 24, or 30 leds which will give me the ability to adjust the output, depending on which substrings are connected.

A note on epoxy. I was negative about this decision before, but it may be one of the better options. It turns out that using thermal compound on the led base, and epoxying the edges has the advantage that they are easy to remove without destroying the led. The disadvantage is that it takes a full day to cure.

Thermal adhesive I hear is much harder to remove and will probably destroy the led is it is ever removed. Tapping the bar and using screws/bushings would increase the time/cost of build and dictate where leds can be placed once drilled.


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## ChrisX (May 28, 2017)

Lowest setting, 18x 3w


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## jeffkrol (Jun 5, 2013)

Neither "heatsink plaster" i.e thermal silicone or 2 part Arctic silver epoxy is terribly difficult to "release" in my experience..

how "permanent" is artic silver thermal adhesive?

Gotta love DIY'ers..


> There's an old trick with the artic silver/alumina two part epoxy in that you can make a 50/50 mix with the non-adhesive type ceramique and the epoxy and it will make it weak enough that you can easily remove it without damaging whatever your heatsink is glued to but still solid enough that there's very little risk for things to fall off on their own.





> If you have space I have found that a good adjustable spanner is ideal to remove stars! Just place it vertically over the led, adjust the jaws so that it grips the star and twist. Way better than hammers and chisels, blades etc imo, tried that, too easy to damage the heatsinks surface that you then have to repair before you can use it again.


YMMV....


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## ChrisX (May 28, 2017)

I'm sure everyone has their favorite way. Epoxy on the edges isn't that bad. 

This setup incorporated 3x 4-4.5K leds and I still think they are too yellow. I may go all 6-6.5K on the other side and compare.


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## jeffkrol (Jun 5, 2013)

ChrisX said:


> I'm sure everyone has their favorite way. Epoxy on the edges isn't that bad.
> 
> This setup incorporated 3x 4-4.5K leds and I still think they are too yellow. I may go all 6-6.5K on the other side and compare.


your running against poor CRI... 4-4.5K can look quite "white" w/ the proper phosphor pack.. or even good binning..


As to the epoxy thing I actually like that idea .. 
Beats drilling and tapping any day esp. w/ these small size screws..
Besides stars are designed for metric screws.. US easy to get screw sizes are either too small or too big....


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## ChrisX (May 28, 2017)

jeffkrol said:


> your running against poor CRI... 4-4.5K can look quite "white" w/ the proper phosphor pack.. or even good binning..
> 
> 
> As to the epoxy thing I actually like that idea ..
> ...


The cost for enough M3 machine screws and nylon washers would have added $30 to the project. Then another 5+ hours drilling and tapping. Current cost of everything $90, didnt want to spend $30 more on fasteners.

I have no idea the quality of these leds. They are supposed to be "epistar" but I have no idea, specs on auction seem bogus.

One thing I remind myself is that the commercial "low end" bars like beamswork are unlikely to be using high end LEDs, they are built to a price. Usually they have all 6500K and some actinic. 

If these LEDS are legit, then this fixture prob equivalent to 2x GreenElement..

Bump: Reason I'm doing all this work instead of buying beamswork, is because I like the enclosed hood design where there isn't any light leakage. I really hate how light spills out of suspended fixtures.

This green element has 32 x 3W over 48". https://www.amazon.com/Green-Element-48-52-Aquarium-Fixture/dp/B00AS4ANUK

Mine has 60 x 3W over same length. Unless the LED output is really bad, I suspect this is a very high light setup.

However, having gone through the build, I now realize the importance of using parts with a pedigree.


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## ChrisX (May 28, 2017)

Wiring question.. If I run a wire parallel to a section of the string, and it contains an on/off switch, will opening the switch bypass the parallel leds? The current will flow over the parallel wire because there is much less resistance on that path. Or will current still be passing through leds?


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## jeffkrol (Jun 5, 2013)

I'm not following..
Constant cyrrenr drivers control voltage(within their working range) to meet their set point..


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## ChrisX (May 28, 2017)

I found some old DPDT (center off) switches.

What I would like to do is have three settings.

A) 18 
B) 18 + 6
C) 18 + 6 + 6

There are two other strings of leds with 6 each.

Need to figure out the switch wiring, pretty sure it can be done.


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## jeffkrol (Jun 5, 2013)

Only can picture it..









Got to look more cloesly at it but 
DP
DT










Yea think it will work..
As shown on the diagram.. Bridge 1 and 3 (ref bars on the right) Left side is plus and minus.
2 and 4 go to the next string..










ONE note: Center off switches are a possibly bad idea..CC drivers wil generally ramp up to full output voltage when in a "no load" condition.
When load is attached thay may or may not react fast enough to the diode string resulting in a period of sever over-volting of small strings...


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## ChrisX (May 28, 2017)

I got it . . .


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## jeffkrol (Jun 5, 2013)

ChrisX said:


> I dont think its possible with DPST (center off). If I could run the leds in parallel it would work, but because of CCD, they all need to be run in series. The off position does not pass any current and the string would be broken.


no need DPDT no center off..still got a slight risk in transition..momentary no contact.


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## ChrisX (May 28, 2017)

Here it is.. Only have to use one half of the switch.


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## ChrisX (May 28, 2017)

First light bar is complete and working great. Doing a burn in to see what the temperature is on the highest setting.

I found these DPST switches in a parts box and they are working great as a three-way switch.

Bump: I have no idea what its PAR is, except that it should be roughly similar to two Green Element EVO bars. :surprise:

The Green Element EVO for 48", has 32x 3W leds.

https://www.amazon.com/Green-Element-Aquarium-Light-Fixture/dp/B00AS479EI/ref=sr_1_6?s=pet-supplies&ie=UTF8&qid=1499367524&sr=1-6&keywords=green+element+evo

My light has 60x 3W leds.

Lowest setting on mine is 36 x 3w (medium?)
Middle setting is 48x 3W (medium-high?)
Highest setting is 60x 3W. (high?)

Next step will be to experiment with different colors of white, possibly other brands.


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## jeffkrol (Jun 5, 2013)

Yea!!!!


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## ChrisX (May 28, 2017)

jeffkrol said:


> Yea!!!!


Jeff,

I'm really happy with this light so far. Thanks for your help.

The drivers are rated 54-105V (from memory) and advised 18-30x 3w leds. That is why lowest setting has 18, highest has 30.

What would happen if I used fewer than 18 leds?

If I can't go lower than 18 leds, one idea is to insert resistors into the "A" path by using the other half of the switch. For instance, when switch position "A" is selected, it currently shorts both 6x strings, and just runs the default 18x. 

If I wired the default string with (say) 14x leds, and put the other half of the switch in series, the other loop would contain resistors to make up the difference so the driver doesnt "blow up" But when switched to B or C, they would be removed. Of course, I could just use actual leds taped up and faced away or something.


What kind of resistor would I use to simulate the power draw of a led with 3.2 FV @ 600mA?

This would be the icing on the cake. This would enable me to pick 3 discrete settings from n-30, as opposed to 18-30.


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## jeffkrol (Jun 5, 2013)

I'm not a hard electronics guy.. Ask me to build a graphics card.. no.. but I can put computers together..
That said I believe this "may' be it.
1.92W @ 5 Ohms..
Wil be interesting to see.

As to drivers.. Seems most will go into "limp mode" where they flash the diodes on/off.


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## ChrisX (May 28, 2017)

Jeff / Anyone,

Do you know if the specs on these RGB leds are legit? I am planning to add some of these in series, but if you believe the specs, a single RGB led has the same power requirements as three individual leds?

For instance, the 1W RGB led shows.

R: 350mA, 2-2.2V
B: 350mA, 3.2-3.4V
G: 350mA, 3.2-3.4V

Does that mean, with a 350mA CCD, that if I ran all colors in series that it would require roughly 8 Volts? If so, this single led would be using almost 3x voltage and probably generate 3x heat. That doesnt seem right to me.


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## jeffkrol (Jun 5, 2013)

It's right. BTW, whats the plan? 
Full spectrum chips are very low green..


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## ChrisX (May 28, 2017)

I have a few options. The simplest is to add colored leds in ratio similar to commercial lights. The F-spec and the Twinstar use this strategy.. 6.5k mixed with similar ratios of red blue green.



















However, to save space on installation, I have considered using RGB combined leds. Individual colors would be wired in series and I could change ratios without having to change leds. I wonder if combineds led would have same look?


Another option is to get one of the RGB controllers with remote, and use it to control RGB leds. Im not sure this is worth the additional complexity.


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## vinay021 (Aug 2, 2019)

Nice project.

Need your help with a project of my own. 

https://www.plantedtank.net/forums/...g-planted-tank-led-lights-liquid-cooling.html

Thanks & Regards


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