# Other Aquarium Forums > Equipment and Accessories > DIY Projects >  DIY 10-CREE LED Light

## Splutter

Hi folks! I had some spare time while waiting for my new 2ftx1.5ftx2ft tank to cycle and I decided to try my hands on some techie work.

I planned to run 10 3-watt LEDs in 2 groups of 5. 


Some of the things that I ordered:

1. 10 x CREE XR-E 3 Watt LEDs
2. 30watt LED driver that outputs 18V and 2A
3. Acrylic sheets customized to size and pre-drilled with holes

Meanwhile, I went out to Sim Lim to get the following items:

1. Heatsink compound (Epoxy kind)
2. 10 x Heatsink
3. 2 x 80mmx15mm Fan
4. 2 x 80mm fan grill
5. Wires
6. Soldering Iron
7. Solder (Lead-Free)
8. 8 x 4Mx25mm bolts
9. 8 x 4Mx30mm acrylic bolts
10. 2 x Lighted rocker switches
11. 8 x Rubber grommets (washer)

Rest of the items from various shops:

1. 1mm aluminum sheet
2. Pre-cut and drilled acrylic sheets to form body

Now for some pictures!

Got a 1mm thick aluminum sheet to mount the LEDs 


Marked the spots to drill holes for wiring. Note that the sheet isn't in great condition since I bought it from a neighbourhood store.


After drilling 4mm holes for wires!


After that, I had to wait for my LEDs and driver to arrive.....

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## Navanod

Nice. How do you plan to seat the light atop your tank bro?
I'm keen to DIY too but I'm still thinking if I should go order all the parts without actually having a plan on how to build and mount the thing

By the way, whats your reason for choosing XR-E instead of newer XP-Gs? And how do you plan to wire that 2A driver? Each group of 5 will get 1A?
Thanks

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## cdckjn

Cool DIY Job. If can, I want to do one as well.

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## Splutter

I'm actually going to house the plate along with all electronics in a acrylic box that I customised.

I chose XR-E because I've viewed many such DIY examples and it seems to be having a high rate of success. The new XP-Gs draw quite a bit more current and I don't really see the need for such brightness. Besides, they are more expensive too. Being my first DIY after such a long time, I'm a little scared to toast some expensive LEDs  :Smile: 

Each group of 5 LEDs will get about 1A. So it's basically a parallel-series circuit. I know it's not best practice to do it this way, but the only drivers that come with suitable voltages for a full series layout are pretty expensive!

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## Splutter

Christmas came early! Each CREE LED is individually wrapped in bubble wrap


The LEDs themselves


After mounting them on the aluminum plate via thermal epoxy


The LED driver - unfortunately not very good (I'll explain later)


Heatsinks to be stuck on the back of the aluminum plate

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## Splutter

Testing connection - it works!


The 2 fans I got to cool things down. Both are rated at 12V, 0.09A from Nidec


The customised acrylic pieces - they cost quite a bit to order, nearly $130 =(


Screwing in my fans after drilling the mounting holes myself. I put in rubber grommets to dampen the vibrations as well.


Snapping in the lighted rocker switches. One for the lights and one for the fans.

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## Cross

Nice finishings with the acrylic. Hope to see the finished DIY soon! Don't mind me asking, is the led driver a constant current driver?

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## tawauboy

have you tried to measure the operating temperature of the leds?

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## Splutter

I wanted to source for a constant current driver but I couldn't get one easily. Looks like only Mean Well has it locally and it takes a while to order =( I had to settle for a normal power supply and I ran into some problem. I'll explain later as well.

I have no means of measuring the temperature of the LEDs but the whole setup was just a little warm to my touch even after running for 8hours straight. I think it's pointless to measure the LED temperatures unless you have the specific equipment to measure the node juncture of the pn gates of the LED itself. Based on the data sheet, those tiny points heat up to >100 degrees.

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## Splutter

So anyway, I ditched the idea of using this voltage regulator as the output voltage wasn't very stable. As I was running the circuit without any current limiting resistor, it led to unstable current load as well. The regulator died out after a while. I went back to the drawing table and opted for a dual AC/DC switching supply instead where I hooked up 5 LEDs + a resistor to a single regulator at 24v, 700mA.


Some of my calculations:

Voltage drop across 1 LED at 700mA = 3.5v
Voltage drop across 5 LEDs at 700mA = 5 x 3.5 = 17.5v
Voltage across resistor required = 24v - 17.5v = 6.5v
Resistance of resistor required = 6.5v/700mA = 9.285ohms
Wattage of resistor required = 6.5v x 700mA = 4.55w

Resistor eventually used : 10 ohms, 10 watts as I wanted to be on the safe side for heat dissipation

I also bought 2 new Mean Well switching regulators at SLT again.


Wired up everything according to this circuit diagram:

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## Navanod

> I'm actually going to house the plate along with all electronics in a acrylic box that I customised.
> 
> I chose XR-E because I've viewed many such DIY examples and it seems to be having a high rate of success. The new XP-Gs draw quite a bit more current and I don't really see the need for such brightness. Besides, they are more expensive too. Being my first DIY after such a long time, I'm a little scared to toast some expensive LEDs 
> 
> Each group of 5 LEDs will get about 1A. So it's basically a parallel-series circuit. I know it's not best practice to do it this way, but the only drivers that come with suitable voltages for a full series layout are pretty expensive!





> I wanted to source for a constant current driver but I couldn't get one easily. Looks like only Mean Well has it locally and it takes a while to order =( I had to settle for a normal power supply and I ran into some problem. I'll explain later as well.


Wow, so the box would sit on the tank like a hood I assume? Where did you get the acrylic cut?
XP-G can be driven at the same amperage and still produce more light than the XR-E hehe, but you're right about the cost.
I saw a meanswell 48V constant 1amp driver that cost about $70 (plus shipping) online. Direct AC to DC too with PWM dimmer. Most likely to be getting that if my project does take off

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## tawauboy

> ...
> 
> I have no means of measuring the temperature of the LEDs but the whole setup was just a little warm to my touch even after running for 8hours straight. I think it's pointless to measure the LED temperatures unless you have the specific equipment to measure the node juncture of the pn gates of the LED itself. Based on the data sheet, those tiny points heat up to >100 degrees.


it's good to hear that the whole setup is just a little warm to touch. just ensure that the 2 fans are running to keep the led temperature low.

you do not need special equipment to measure the junction temperature. it can be calculate from the datasheets provided. these cree leds have a thermal resistance of about 8deg/w from p-n junction to solder point. so if you are running the leds at 3 watts, the temperature difference between the p-n junction and solder point is 24 deg. you can measure the temperature of the solder point.

you'll want to keep the p-n junction temperature below 80deg.

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## Splutter

Acrylic was from Dama. They should be pretty easy to work with.

tawauboy, thanks for that information. I'm still monitoring to see if there's any spike in temp.

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## Splutter

My girlfriend helped me with the acrylic construction and I think she did a very nice job =)


The acrylic bolts I got to screw in the tail plates


The new 10 Ohm, 10 Watt resistors I got to limit current


The new Mean Well voltage regulators - 24v, 700mA


How everything looks after powering up!

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## neverwalkalone

Nice journal, and great job on the DIY Bro Splutter. ;-)

Would you mind sharing the cost of the items you listed?

Agree with you that Current Regulators are a pain to source; and expensive - found some at Sim Lim Tower but there are too ex, mostly IP6x rated (waterproofed) which in my mind is not necessary.. 

Was contemplating building my own Current regulators using National Semicons (LM3404s) but haven't been able to find them (online are bulk orders)... open to hear what other Forummers have in mind on building such Current Regulators. I feel using using the 'ready made' regulators (buck pucks etc) are too expensive IMO.

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## cdckjn

Good write up on the details! Great and Nice looking Lights!

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## tawauboy

> ...
> 
> Was contemplating building my own Current regulators using National Semicons (LM3404s) but haven't been able to find them (online are bulk orders)... open to hear what other Forummers have in mind on building such Current Regulators. I feel using using the 'ready made' regulators (buck pucks etc) are too expensive IMO.


try looking at digikey and avnet express websites.
they offer small quantity purchases.

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## illumnae

I'm planning on using Buckpacks ordered from www.ledsupply.com

They seem pretty compact and affordable, and are efficient for just stringing sets of 5-6 LEDs, which will help in my eventual "automation" project using an Arduino, where I would like to light different banks of lights at different times.

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## Splutter

More views of the final product =)

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## neverwalkalone

> try looking at digikey and avnet express websites.
> they offer small quantity purchases.


Thanks Thomas. Forgot to check those sources - just relied on Google and NS' distributors...

Bro Splutter: Nice Full Tank Shot. 
If I may comment - the hardscape is alittle too 'short' for the 2ft height IMHO.

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## nikochan

Wow! this is very impressive! hmm.. is it even worth making a 1Cree LED for my cube tank?

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## Splutter

Sigh I also wanted the hardscapes to be slightly taller but I can't find any suitable ones and I just didn't have the time to wait anymore.

nikochan, I think it's not really that worth it unless you are modding some existing lighting fixture. This DIY isn't exactly cheap, I'm doing it more for the fun of it =)

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## sufan

Wow, I absolutely love your DIY LED lights. They actually looks very professional custom made unit. The only suggestion that I have is that the metal sheet would look much better if it was made from mirror polished stainless steel. I have a questions, do you think you get enough light for the tank from the LED? If so, what the equivalent of the TL in wattage?

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## Navanod

Bro sufan, that metal sheet of aluminum doubles as a heatspreader. Stainless steel would not be as good for that purpose.
Aluminum can also polish to a mirror though, haha, if splutter had the elbow grease to do it  :Smile:

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## Inwares LED

very nice craftmanship! looks very bright. Will the fishes go blind or not? hehe...juz kidding.

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## Matt.Lee

Bro Navanod,
Why not use copper sheet? It is also use as a CPU heatsink in our computers. Surface can be polish to shine.

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## Splutter

I did try to polish the aluminum plate, but I think I made it worse, haha. It's definitely possible to make aluminum shine, but you'll need a orbit sander and it'll probably take a good 4-5 hours of polishing still. Copper works too I guess but you'll have yellowish lighting due to the reflections, besides copper oxidises pretty easily and the shine won't last. Not to mention copper is extremely toxic for shrimps/snails if water somehow gets in touch.

The lighting isn't as glaring as I thought it'll be, probably due to the height of the tank and some oil at the surface diffusing the light. I actually bought reflectors as well but didn't use them in the end as it caused hotspots.

I was hoping to see some pearling from my moss, but that didn't happen. I'm pretty new to this hobby so can anyone advice if this is due to mosses not pearling in general or is it due to other parameters like no CO2 etc?

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## Navanod

> Bro Navanod,
> Why not use copper sheet? It is also use as a CPU heatsink in our computers. Surface can be polish to shine.


Oxidation of the copper would turn it green in no time! and it more expensive




> I did try to polish the aluminum plate, but I think I made it worse, haha. It's definitely possible to make aluminum shine, but you'll need a orbit sander and it'll probably take a good 4-5 hours of polishing still. Copper works too I guess but you'll have yellowish lighting due to the reflections, besides copper oxidises pretty easily and the shine won't last. Not to mention copper is extremely toxic for shrimps/snails if water somehow gets in touch.
> 
> The lighting isn't as glaring as I thought it'll be, probably due to the height of the tank and some oil at the surface diffusing the light. I actually bought reflectors as well but didn't use them in the end as it caused hotspots.
> 
> I was hoping to see some pearling from my moss, but that didn't happen. I'm pretty new to this hobby so can anyone advice if this is due to mosses not pearling in general or is it due to other parameters like no CO2 etc?


I think I saw the spiral polishing marks on the plate in one of the pic! hahaha!
I just got my XP-G R4 torchlight and did an estimate. It can only cover 1/12 of my 2x1.5 tank surface. But then again, its kinda underpowered as its on batteries. Now to save up for that DIY project

Bro, for pearling to happen, you need stable CO2 injection at 30ppm. Otherwise, blasting lights into the tank will only grow algaes

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## Matt.Lee

Bro Splutter,
Where did you buy these 10Ohms 10W resistors, cost? From your picture, they look like ceramic power resistors?

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## Splutter

Hi Bro,

Can get them at most shops in Sim Lim Tower. Should be around $2 for 1.

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## madi

wah... nice.. now i know the easier way to power up LED... hahaa.. for now i'm using this circuit to limit the current..
http://www.instructables.com/id/Supe...3/Assemble-it/

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## jamesneo

I have a noobie technical question. 
I have a typical AC to DC adaptor with a output DC 12V and 0.8A.

Cree LED spec:
- 3.7V typical driving voltage
- Manufacturer Rated 228 Lumens at 1000mA input current:
350mA: 107~114lm
700mA: 171.2~182.4lm
1000mA: 214 ~ 228lm

1) Can i use this to power up say 5 CREE LEDs since the specs say it has only 3.7V driving voltage?
2) Why do we need to use the LED driver since the AC to DC adaptor have a rating spec which could do the job?
3) I just saw my notebook power cord AC to DC adaptor output as 19V, 4.22A, This is more than sufficient to drive 10 CREE LEDs?
4) A typical 36W PL light lumen output is 2800 Lumen. If the LED CREE lumen is 228lumen, so i have to buy about 2800/228 = 12 LED to achieve 2800 Lumen? 
5) A 36W PL cost $10 while 12 CREE LEDs will cost S$80, isn't it more expensive ??? 

Thanks

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## neverwalkalone

James, I'm not an expert in this area, but if I may give some inputs:




> I have a typical AC to DC adaptor with a output DC 12V and 0.8A.
> 1) Can i use this to power up say 5 CREE LEDs since the specs say it has only 3.7V driving voltage?


5 LEDs in series will be 5x3.7V = 18.5V, not enough from your 12V adaptor to drive; so the max you can go with this 12V adaptor is 3 LEDs (max out at 800mA). Having said that, I would not encourage you to use just an AC-DC adaptor without additional electronics for this purpose (as much as some of the shops at SimLimTower are telling you it's fine to do so)...




> 2) Why do we need to use the LED driver since the AC to DC adaptor have a rating spec which could do the job?


Strictly speaking, LED drivers are (constant) CURRENT supplies, which ensures that the LEDs are driven with the same current (limited). What you see in most simple designs (eg instructables.com,) are using voltage supplies, which is not ideal, but gets the job done.[/QUOTE] 



> 3) I just saw my notebook power cord AC to DC adaptor output as 19V, 4.22A, This is more than sufficient to drive 10 CREE LEDs?


Again, going back to #1, you could potentially wire up 2x5LEDs in parallel, which the 4.22A can easily drive; but I wouldn't do this if I were you. The parallel circuit will need some form of 'current balancer' to keep the currents in the 2 LED strings the same, so that it won't damage the LEDs in the event an LED blows/shorts. You can get it to work with a simple circuit, but it's not safe, nor power efficient. You seem to have done some reading on the LEDs, (amperage/lumens etc), I suggest additional reading on the LED driver circuitry, even if you're not a techie. It should not be too complicated beyond Sec2 Physics, unless you're into designing from scratch with transistors. ;-)




> 4) A typical 36W PL light lumen output is 2800 Lumen. If the LED CREE lumen is 228lumen, so i have to buy about 2800/228 = 12 LED to achieve 2800 Lumen?


Looking at lumens alone is not the best measure of "effectiveness" of the lights. I suggest you google search the differences between the aquatic lighting solutions and understand what I'm saying. PAR (or PUR) is the more accurate measure, but most (all?) of us have no access to such. Suffice to say, LED lights are more "effective" than other lights, which explains why the trend towards them. For all intended purposes, 6-8 (3W) LEDs will probably be enough to replace a single 36W PL lamp (assuming its to light a 2x1x1' tank)




> 5) A 36W PL cost $10 while 12 CREE LEDs will cost S$80, isn't it more expensive ???


LEDs are still considered fairly 'new' technology, and it will still be more expensive (though the prices are falling quickly, capabilities [eg brightness/lumens-watt] improving). You need to ask yourself why you're going to use LEDs - environmentally friendly (no mercury FLs to dispose), less power consumption (though at 36W, your $s saved is probably minimal), less heat, dimmer control, colour variety [eg moonlight blue] etc etc.

If it's purely a $s decision, I'd say the PL lights (at 36W) is still a much cheaper option. But like all technologies, expect this to be a viable option in the near future. You can already see alot more LED lamps for both normal use and specifically Aquatic lighting. 
Hope this helps.

Cheers

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## jamesneo

Hi neverwalkalone,

Thanks for your great info. You have answered all my queries. 
Cheers.

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## Splutter

Hi James,

Just to add on. LEDs will have a throughput current based on the voltage that's across it. It is very very important to make sure that the voltage across the LED doesn't exceed the specifications or the current though the LED will shoot up exponentially. When this happens, either the LED blows or your power supply overloads and blows. Thus, it is necessary to have a resistor in series to limit the max current. Hope this helps.

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## jamesneo

Thanks Splutter.  :Smile:  Will keep that in mind when planning for the DIY. 
For the time being (after doing all the calculations), it's not within my budget at the moment.

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## briandang

> So anyway, I ditched the idea of using this voltage regulator as the output voltage wasn't very stable. As I was running the circuit without any current limiting resistor, it led to unstable current load as well. The regulator died out after a while. I went back to the drawing table and opted for a dual AC/DC switching supply instead where I hooked up 5 LEDs + a resistor to a single regulator at 24v, 700mA.
> 
> 
> Some of my calculations:
> 
> Voltage drop across 1 LED at 700mA = 3.5v
> Voltage drop across 5 LEDs at 700mA = 5 x 3.5 = 17.5v
> Voltage across resistor required = 24v - 17.5v = 6.5v
> Resistance of resistor required = 6.5v/700mA = 9.285ohms
> ...


can i check with you that can i use a swith with 5A not only 700 mA as your design cause if you buy 1 save your cost as well. As i know that with 5 A can supprt to 07 mA each.
pls correct if i wrong.

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## Splutter

Hi,

I'm not sure exactly what you are asking about but the switch used is rated up to 13A. You can of course use just one if you are sure the fan is going to be on all the time, I wasn't so sure back then so I got another just in case I didn't always needed the fan. Regarding cost savings, it's not going to be much since the switch is just $1.

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## briandang

oh. i mean it is AC DC Switching? not the switch as you mean.

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## neverwalkalone

Briandang, 
I wouldn't advice using too high (5A) a rated supply if you are to follow brother Splutter's circuit, as there is really very little protection against a runaway current in this design (no offense to brother Splutter); ie imagine a 'worst case' scenario of the full 24V applied across the resistor (assume all LEDs shorted/have zero voltages), that'll be 2.4A! (24v/10 Ohm) - in his case, he is using a 700mA limit on the meanwell, so that is the limit the LEDs will get, preventing damage potentially.

Ideally, the DC supply should be going into a "buck" regulator, which will ensure a CONSTANT CURRENT to the LED string regardless of the voltage drops (which will vary as the temperature changes in the LEDs).

Using a much higher amperage supply will imply that potentially your circuit can reach that upper limit, which is dangerous. There are a number of DIY LED project threads on our forum alone, and bro EdwardChuaJH has done a very good writeup on his project. I urge you to study them (and the many others available online) before designing/wiring your circuit for safety reasons.

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## jamesneo

Hi,

My 2x 36WPL light (light now is slightly yellowish already) is due to change after Chinese New Year. I did some research and read up on items to purchase on the website as well as some of the information here. Here are some items that i want to purchase:
1) LED Driver– Waterproof 1A 30W Power Constant Current Source LED Driver (100~240V) x 1piece

2) Cree XR-E Q5 Emitter on Premium Star (228LM at 1A) x 08 pieces 

What do you think? Total cost is around $80+ to replace the 2x36WPL tube (Assuming i spaced out the 4 LEDs at 12cm apart to replace 1 x 36W PL) . 
Is 08 CREE LEDs enough or should i use 10?? 
Is the LED driver rating suitable? 
I am not planning to use any 10W resistor. Is that alright?

Thanks and Happy Lunar New Year. Huat !!!

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## iewnuj

You might want to get a 700ma driver instead. Not worth driving the leds to their limits, since its not going to be much brighter and there will be less heat issues too.

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## li_gangyi

If there is enough demand, I can make PCBs that'll turn normal power supplies into constant current sources. PM me with your specific design (input voltage, amount of LEDs and required current) requirements and I'll churn them out. Great way to turn those useless laptop adapters into something useful xD.

Using a power supply and a fixed resistor to set the current is non ideal as slight variations in output voltage will result in changes to the current, as well as during initial turn on (PSU may overshoot). Differences in forward voltage drops across the LEDs themselves will change the operating current, calculations will get you into the ballpark (which is good enough for stuff running at say 20mA for indication purposes) , but not really ideal when you're running high power (overdriving them above design limits will cost you LED life, and $$$), best if you go this method is to verify you're running at a safe current with a multimeter after you've put everything together, the forward drop will actually vary with life and current (check the datasheet for nominal values). 

Controlling LED junction temps are important as well, the temperature will affect colour, as well as overall lifetime. Best to run them at a nominal current to get more life and use a few more LEDs for the required brightness.

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