High Power LED Tutorial #1 - How to Drive 1W and 3W LEDs from 12 Volts 

Julian, you are THE BEST explaining easily how to drive LEDs!! THANK YOU!!! I'm learning a lot with your videos!!

You skipped the part where you say you set the voltage to 3.3V for the single led setup. Other than that truly great video and explanation. Cheers!

No problem. In fact if you look through their products, you'll find a 1W LED driver with EN input (for PWM control) for $4.37 which seems pretty reasonable to me. It's got a "Make Offer" thing too, so you could probably get 10 units for quite a bit less than that.

I see many from this manufacturer with a third pot between the other two...what is that for? Duty cycle or something? Is it so you can use the driver as a dimmer or something?

Went through full loud shooting apes in the internet jungle, started being desperately entangled in inextricable intellectual porridge, then sinking stuck in quicksand thought when i saw the regulated Led light....Tarzan julian saved me... Thank you a lot! that's one good tutorial.

So you want to put a 50W heat source inside a thin metal tube? Sounds like you'll get your fingers burned... quite literally!

Try searching eBay for "RGBY Quadcolor 4*1Watt LED Built-in Driver Board LED" by Sure Display. It has 4 drivers on one board with PWM control inputs. The LEDs are pre-fitted but could be removed. Sure Display may have other driver boards that would be suitable.

Minute 3:43 what is name of this board? Tanks

Yes - that should be OK. Three LEDs in series will need about 10 volts, the buck regulator should be able to supply that from a 12v input, but you'll be near the limit with 2v difference between input and output. 2 rows (or columns depending how you look at it) will require twice the current of a single row - 2x 700mA is 1400mA. This should work.

You can buy dedicated 1W (or 3W) LED driver modules with an E (enable) connection for PWM control, but I can't think of a way to drive 10 separate LEDs from one driver module if you want individual control over each LED. You'd probably need 10 driver modules.

I think the 3rd pot is something to do with charging batteries. It alters the point when the fully charged LED comes on. Not completely sure about that though. The unit with the larger coil (with the visible windings) has a higher output current rating.

Awesome information! In the process of designing custom shaped turn signals and brake light for my motorcycle. So this helps immensely with the wiring issue.

I want to use the 3W RGB high power LEDs to light some fiber optic fabric in a costume. I've I'm only using 3.7V Lipo battery how hot will they get. If I put them on HeatSink will it be safe around fabric? Everything I read says those little high power lights get really really hot. Thank you!

You're absolutely right, for prolonged use, the 1W LEDs should also be properly heatsinked, so buying them on the star boards is a good idea. Also I was using them in free air outdoors - if they're in some sort of enclosure, the heat build-up could be quite rapid.

Try a search for "buck converter CC CV". There's one for sale by Bisany and another by Polelu.

Outstanding video. I'm a beginner at all this but am currently trying to design a CREE XM-L T6 LED system for my motorbike, so this was exactly what I needed to see. Well done.

can you put LEDs in parallel like that????? I don't think so.

You can see the mismatch at low current, but wind up the power and it all looks good.

Excelent, julian. I do not like to connect leds in parallel, but if they are all the same thats ok.

I did a quick search on eBay for "1W red LED" and found some with 655 - 660nm wavelength.

Very surprised you don't have an Amazone link in the description as you'd earn money just from people browsing there, as long as the cookie stayed ni their cache for 24 hours.

Hi Julian, Firstly, may I compliment you on your videos. Of all the electronics videos I have watched to date on RU-vid yours are by far the best. Not only are you extremely clear and concise in you explanation of everything, but equally you ensure that what is important is shown on camera. I am slowly working my way through all you videos as they are a wonderful resource for so many, at all abilities. I am now unfortunately disabled and have been looking for a hobby I can manage from my wheelchair, electronics appears to be the ideal thing but I am very much a beginner. I’m sorry to be cheeky but I wondered if I could ask you for some advice please...my little grandson has a 12v battery powered “sit on” car and although I will not be able to fit everything myself I want to build a LED lighting project that my son in law can fit. I saw a video a while ago that shows the functionality that I would love to achieve and tried contacting the author. Unfortunately he is probably a very busy man and failed to respond. The video link is here: m.ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-pD-InblYDlk.html He mentions buck converters which I have investigated, but based on the type of small battery installed in these toys my research thus far seems to indicate think maybe buck/boost (or is it boost/buck) would be more suitable. With my very limited knowledge I have looked everywhere I can think of but cannot find one suitable so was therefore wondering if you could please possibly advise me accordingly as clearly you know this stuff inside out? The criteria that I am aware of appears to show the following considerations... 1. 12v battery Vin (I would guess this would vary as the battery is run down by use) 2. be as efficient as possible to minimise drain on the battery 3. have the ability to set both output voltage and amperage 4. be Arduino controlled so needs some form of “enable” or “switch” control 5. due to possible issues with heat I am guessing that 1w LEDs will be the brightest type I can use, and as his car only has 2 lenses on the front I’m envisaging that the largest circuit will consist of just 2 of these 1W LEDS. I’m guessing you’re a busy man too and although it’s going to take me a long time to figure all this out, simply by knowing which buck/boost converter to use will help more than you know., and based on some of the comments on the video previously mentioned, plus all the other online videos showing similar projects I think you could make a fortune if you designed and sold a schematic and/or circuit diagram for such a project. Sorry to bore you with all this but I’ll keep my fingers crossed you kindly reply. Thanks. Kind regards, John PS. Could you also please possibly list the 3 boards shown in this particular video? Thank you again

Julian, thank you for your thorough and complete videos. Have you tried, or do you know if it is possible to regulate the intensity of the led’s in this array with an Arduino and mosfet using PWM in between the buck converter and the led’s? Thank you for your time.

What's the exact name of the regulator. (Ex:lm2317)

3 watt show more simple for a MOTION SENSOR AND TRANSISTOR AS SWITCH AND 3.7 LITHIUM(4.2VOLT)AND HEATSINK AND DIODES FOR POWER REDUCTION MAYBE?THANKS

What's the thing you're using to adjust the pot I always find it a pain to use a screwdriver on them

I'm wondering what would be a good solution for a traffic director like this: 36" Amber Traffic Directional Advisor Strobe Emergency Warning Arrow Stick I don't have a problem using smd parts, but wondering if there's any single-chip drivers, or a driver that would have some circuitry like one of these boards but multiple leads off it that I could switch with a micro and not blow anything up.

Hi Julian! Your videos are very brief and easy to absorb for any newbies or experts. Thanks and continue with the videos. BTW, those high power LEDs such as 20,30,50 and 100 Watts do come with the Drivers incorporated into the LED itself. So we save on power supplies and drivers but we pay a little bit more on the LEDs. Do put up a video on these new ones please! Bye!

Thanks - the converter in the video uses the LM2596

P =V x I, so if it's 1 W, then 1/8.7 gives a current of 114mA. Not 300mA. Then P = I squared R, 1W = 0.114 x 0.114 x R, R =75 ohms. Use this resistor and you have no problems. You cooked the last one because you used a wrong resisitor. 33ohms is ~half the size required. Im not sure where you got the 300mA current from? I've used this method for years on all my led installs and never had a problem cooking any resistor, and the leds run cold as ice. I also don't use the Vf. I use the full voltage in case of a failure. So I would use 12V as the Voltage, not 8.7. Ive got my whole shed setup running 24 V leds on 2 12 V car batteries of 25Ah each in series and my house with 12 V batteries in parallel with 12V 6.5 W leds. I measured the current through the circuit first in the shed for each array and saw it was 600mA, and using the power calculation worked out its 14.4 W. Working it out is gives a value of 40ohms. So then the resistor I use is 15W and couldn't find a 40 so I use 44ohms. And resistor are cheap, so a little bigger is not an issue. I think they were $1.80AUS each. Ive had no issues with house or shed so hope I'm not doing anything wrong !! 😬

One question. I want to connect a 3w LED with a 18650 battery. (Yes, I'm going to use heatsink and so on). But I just can't find the proper driver for it in my country and buying it from China takes almost 3 months to get here... So, any idea of what can I use? Thanks!

Hi great video, Julian.Could you help me a bit? I'm making 100w panel ( LED 3w [2.2 - 2.6]v 700mA ) and i dont understand one thing. I will use computer power supply it gives 12v and arround 10 A. I'm thinking to connect buck power regulator for 5 LED in series and 14 row's. And the question would be, if one of the row's wouldn't work, so rest 13 row's would share that 700 mA? leading to massive LED's burn out? If yes, how i can protect my panel from this accident. Thanks for anwser.

HI This is perfect for me thanks. However, if I want to put a Pot or rheostat type device on this to drop the voltage and therefore dim the LED's - where would I put it? Will the VR try to keep the voltage up if I put it in between VR and battery?

Which module I can Use for drive 12V Led Strip on 12V Battery?The Linear Lm317 have too much Drop Voltage.Thanks for your Videos

Hi, I have current source 900ma box. Input ac 220, output 12v labeled - Led and + Led. My Led 3 w, star Led same as on your video. My question can connect this Led direct as the box labeled which in this case I’m putting 12v on the Led or I should connect a series resistor which can drop the voltage across the Led? Thanks

Yes, if the LEDs are in series.

I'm trying to complete a project but need some additional info. I want to power a 3w rgb led for a project but I was told I may have an issue with the heat that they generate. I want to put it in a headlight housing so space is a factor would I be able to have a heat sink that will work properly in a tiny space and if I used the same board to power the led what could I use to control the color

Dear Julian Great videos you have. what>model Buck>converter is this. The>Current buck converter ? Gr

Hi, my microscope led is the 3 watt star model. I burnt out the original circuit board because I plugged a 12 V wall charger instead of the recommend 5 V. So my question is can I use this led with a buck converter to allow a normal generic 12v to power it? Also need a dimmer switch attached to control brightness. Does anyone know how to go about this ?

Hi, i need replace autobulb 21W/12V from reverse light. I can use 6x 3W smd led with only resistor? How to doo? Please help me

Hi there, can you please tell me what will happen if one string of led connected to CC driver fails to operate, as per my research it'll divide the total current into remaining string which as a result would damage them causing the whole system down. plzzzzzzzzzzzzzzzzz help

Would it make more sense to run a single 50w led or 3 x 13 3W leds? The 3W leds only need mounting on those 20mm star heatsinks. were as a 50w single led needs a massive heat sink. Would 13 x 3W leds give the same heat output all together as the 50w led? The main problem I have is the heat.

Great video! I like that screwdriver cover for those annoying screw slots. I think I'll start using small alligator clip covers like that.

Hello Julian i've purchased the same voltage and current regulator to drive 3w leds , i' ve set the voltage to 3.3 v and the current to 700 mA as instructed on the data sheet however the led only drew 200 mA am i doing something wrong or it's just the quality of the leds . it's mounted on an aluminum heat sink and i got an additional heat sink but it did not heat up can you kindly advise ?

From 230v ac I need to connect 20 1 w led so I think one rc circuit with buck converter I can use ? 66 volt 300ma I require

Both would work.

"the resistance is not happy" :-)

Hi Julian! thank you for your videos , why do we need to regulate the driver voltage output if the current is already regulated ? thank you

can't you just stick a coil in series? any sudden change in current like a massive spike would cause a voltage drop across it and save the leds? :D

Hi, Julian Can I get ckt diagram for the same?

not only the current is tge issue, the led will burn itself out without a heatsink

Hello, I have a moped and I'd like to replace the original lightbulbs with LEDs, the alternator is producing 12V AC, first I have to rectify the current to DC but the voltage increase with the RPMs... If I have something like 6-19V at the input of the led driver, it would be ok? Thank you! :)

how can i find a circuit like this,? voltage and current control

Hi Julian. With 14 volts in the input, can I have 9 volts in output using the kit showed in your vid?. Regards from Italy.

The old ones are the best... I meant the video not you. 😉

Sorry Jules...we're into 100 watters now

The one I have from banggood has three blue boxes with adjustment screws. Would be nice if they had labels or a link to documentation online.

hello Julian Llett just saw ur video very helpful and solved many questions of mine as well...really great job done :) but there is a question it wuld be great if u help me out on this i am making a light panel of 80X1 Watt led's with heatsink one's the only problem is what dc stuff shuld i use..i am not much in electrical stuff but i am posting the specs for one bulb and its like this 1 led is of 1 watt consumes 3 - 3.5V and takes 150mA now can u solve this one how do we use 80x1 Watt leds it wuld be a life saver and amazing video cheers To you Man!!!

A few words of caution, I have recently bought a current and voltage controlled circuit off E-bay, I wanted to push a constant 150 mA of current through 6 luxeon LEDs from a 12 volt DC battery supply, underdriving them by a long way and cooling them with oversized Aluminium heat sinks because I want them to last virtually forever. I carefully set up the circuit to limit current to 150 mA and the voltage was set well within limits. However, I made the fatal mistake of hooking up the power to the circuit and then connecting the LEDs to the circuit. This created a sudden surge and pop went one of the Red Luxeons, not much of a problem normally just replace it, except the LEDs were carefully installed on heat sinks behind tongue and groove wood panelling, the whole episode cost me a days work. Finally, I decided to use a voltage boosting circuit only and run it through an LM317 circuit I built a while back to limit the current, again a big word of WARNING here, avoid the simple ONE resistor only LM317 current limiting circuits, build one with a potential divider as I did. Because I bench tested on breadboard a simple LM317 circuit with a single power resistor and the damn thing allowed an initial surge of around 2 AMPs before settling down to the required current flow. In summing up the whole experience was dreadful and I hope I can save someone similar problems, always hook up the LED side first before powering up, check and check again on a bench test first before you even get to that stage, one more thing I did after this incident is I installed a 100uf 25-volt Tantalum Capacitor across the plus and minus rails to the LEDs, on powering up this effectively causes a momentary short circuit across the LEDs, forming a shock absorber to buffer any current surges. Bear in mind a capacitor across the LED supply rails could make things worse if you were to power up and then connect the LEDs up downstream of the Capacitor. I hope I have helped people avoid the problems I have just had to solve.

What is the common name for voltage-current regulator? Please newbie here...

Really Illuminating ! Now I know why there is a circuit board at all, in my Li-Ion Battery housing;_in my wheelchair_. :::::::::::::::::::: Can I ask you, I have an LED light on my balcony. The light fitting says 4Watts but later on the Internet the manufacturer's company says that that item "says that the lamp is 4W but in fact it uses 13 W, in electricity". . Why so, the difference in the specification label ? . If you have no idea because I have left out some data in my question description, then I'm sorry for posing the question with a mistake in it; kindly ignore my whole enquiry. . Cheers. from, del-boy

Please clarify this. The battery you are using is 7ah, the buck converter you have used can only take up 3amp (max 3amp input), you have connected it directly without any resistor. Why didn't the buck converter burned up? What if I connect my 105ah battery directly with the buck converter I have which input max current rating is 3amp, will my buck converter blow away? Please some one answer ASAP. Thanks

I think I have worked out that the whole point of the driver is to limit the current enough so that the LEDs won't flicker when the voltage supply changes? I'm not sure if you said it like that or not. My LED string was drawing 155 mA without the driver and I turned down the current to 139 mA to make the flicker acceptable as my servo (wired in parrallel) was rocking back and forth).

Can you help me 'how to' safely connect 12 pcs 1W LED (3.3V/350mah) to 12V car battery? Thanks

You said that it's impractical to use resistors with high powered LED's - Is that still true if you're running them from a more consistent power supply, such as a 12V power supply, plugged in to a wall outlet?

Thanks for the video, I am making a UV resin curing lamp. How come you did not try 4 LED 3 watt lamps in series from the 12v battery? Did you give it a try? The bulbs I got were 3.2 to 3.4 volts

Hi there, thanks for the video. I don't understand one thing if you don't mind me asking. When you have a voltage regulator, do you setup the voltage to a exact amount like the amps? Like if the Vf of the led is 2.2 you would set for exact 2.2 and also limit the current? Last question. sorry to bother :). What about led drivers? are they a good option?

Informative and well presented. Thanks Much. ...... One day they'll make LED's that self limit the current??

Hi Julian. I got chinese 3W beads from aliexpress. using small buck-conv. with one trimmer on it: I set it to 3.4V, than measure Current to be 50mA (0.05A) , R = 3.4/0.05=68ohm. To list : 2.4V/0A=99k dark led; 3V/0.025=120 ; 3.2V untested ; 3.4V/0.05=68 (if 48.5mA R=70. 3% delta); 3.6/0.6=60 ; 3.8/0.075=50 ; 3.9/0.087=45 (if 97mA R=40. 11.5% delta ). Questions: 1. unsmooth form of R line 2. NOWHERE NEAR 300mA in your Ohm Law calc. could you enlighten US ? thanks

Ok......I bought some drivers on Ebay and they work good for 3w led's, which it says they are rated for. I think that the specs they give are wrong? Here is copy and paste from listing Also, these are NOT adjustable. ......Input Voltage: DC/AC 12 Rated voltage: 6-12VDC Frequency: 47HZ-63HZ Output Current: 300mA±5% Efficiency: ≥92% PCBA(L*W*H): 18*12*13mm Drive power: 1*3W....... I'm seeing more like 800ma current draw. So, these specs are wrong, correct? Next question...I ordered some other ones that say good for 1 to 5 1w led's. Do these possibly have some built in feedback to adjust voltage? I have not received them yet but they look the same. These drivers are driving me nuts!!!!!! : )

so i got a 30W led. whats the best way to set it up for camping use. and i am a total beginner. i really know nothing. i just want to make a bright camping flash light or torch

Hi Julian I must say I really enjoy your videos,even ones that I have no interest in, I just enjoy the tech aspects that you explain in detail.I am starting a project in replacing my 4 ft. shop lights.I could buy the new led fixtures but I enjoy the diy aspect Here is what I have in mind, Am planning to use the Epistar LED Emitter: 3W - Output Lumens: 180-210 Lumens - DC Forward Voltage (VF) : 3.0-3.4Vdc - DC Forward Currect (IF) : 700mA - Color Temp: 6000~6500K ( White) - Beam Angle: 120 degrees mounted on a heat sink in parallel 8 leds per fixture for a total of 48 leds. The question I have is I have several old PC power supplies that I would like to use for power.I know that I will probably need voltage/current buck converter to regulate power, will one 300 watt supply work or do you have a better solution as this is my first led project Thanks

Hi, a long shot asking on a video so old, but I have one of these constant current / voltage boards, I set it up for my IR 10W 5-6V 850-1000mA LED as Max 950mA and Max 5.5V, it seems to be getting fed the 950mA but when I do a voltage check on it, it only show 4.5V, any reason this might be?

I have another question perhaps you would know what is best to do in this situation, I want to drive a total of 6 uv lights with the 12 volt battery I need to find the 365nm type lights and would this controller be the best solution?

what is name of model. please

I want to use the 1W LEDs for a model kit using only a single coin type battery like in the beginning of the video. Is it necessary to use a resistor and will it get hot enough to damage plastic?

SORRY FOR RAMBLING SIMPLY THESE CHEAP MOTION SENSORS AND 3 WATT LEDS ARE PERFECT FOR AN EASY DIY PROJECT.3 WATT LED,HEATSINK, MOTION SENSOR,TRANSISTOR,Photoresistor,3.7V LAPTOP BATTERY AND POSSIBLY CHEAP SOLAR CELLS AND THE LION RECHARGEABLE CIRCUITS TO KEEP CHARGED AWESOME MATE

Hy ! I have a question how to put a 1 W LED in my Makita lamp who have a ni-cd battery 9,6 v 1500 mA.Now i have on the lamp a regular bulb lamp but i wont to change with a led lamp. I think that 1 W is inaf for light on these lamp or I must put 3 W ? What led must I buy and can he work with only adding a resistor for adjust current ?? Sorry for the bad english because I am for Croatia. Can you give me an answer ?? Thanks Dario

For step up you just need a step up converter (boost converter). They look very similar and are similar in price, they are perfect for wiring up a whole horde of LED's in series. You can turn 12v into 33v and run 10 LED's in series. I usually run each LED at around 3.3v, a bit under the 3.5v rating.

Hello, thanks for the video it's very helpful - but I'm still a little confused about how to regulate my high power LED. I have a CREE XM-L2 U2 LED, which wants 3000ma at 3.5v for maximum power. I have a voltage and current regulator like the one in your video, it can deliver 5A. Do I need to regulate both the current and the voltage into the LED, or just the current?

I have bought 5w 700 mA LEDs that need to 6-7v to work . I want to install these LEDs as DRL in my car . I want to install 4 LEDs on each side using a cc cv module. Can u please help set the voltage and Ampere on the cc cv module to run 4 LEDs with car battery. Ill be thankful to you if u let me know the proper output voltage and current on the module to make the LEDs work without burning them

Hi, I made myself for a spare time hobby a small 3D printed desk lamp, where I'm using a simple joule thief circuit to drive 3 of the 5mm white LEDs in parallel from a single AA battery. I bought a 3W white LED in order to make it brighter. When I connected it instead of 5mm LEDs, it lit a bit dimmer due to voltage drop. Checked with a multimeter: JT provides total of 22V through a diode without load and when I turn on the LED it drops to 2.3V at around 24mA current, I know that max. voltage for this LED is around 4V at higher current. Any ideas what shoud I modify to provide it with sufficient current? Do you maybe have good and simple references for this? Thanks!

great video, very useful, thank you. Would it be possible to tell me the manufacturer and part-number of (a) the switch-mode voltage & current regulator and (b) the 1W LEDs that you used?

Hello, Thank you for the video! Does the output current remain constant throughout the battery's voltage drop (without adjusting)? Thanks!

Hi Julian, Thanks for sharing. I am a big fan of yours. I wonder if you could help me with a schematic of a circuit that can regulate voltage and current built with 2 pcs. LM317. I would like something like the one you demonstrate in the video with LEDs for voltage and current.Thank you in advance,Henrik

The accurate power supply control to the led is interesting and the problems caused by the alternator kicking in on a car to charge the battery. In car specific led exchange bulbs do they have any sort of regulation or resistance on board and are they doomed to failure more rapidly than the incandescent filament?

Could you use a pc power supply as your power supply. 12v 24a which i'll regulating to 12v 1.4a? I'll be adding a heat sink behind the lm2596. would that help?

Thanks for this post Julian .... where do you get your buck converters from. Mostly Ebay? Some no doubt are better quality than others.

The output still depends on the input though, when the voltage deceases in a battery the buck converter wont be still putting out the same converted voltage, it will lower. And it's the same if the source voltage increased (like your example of the alternator). An LED can have the right current, but if the voltage is far too high the LED will still burn out as voltage times amperage = watt power. So you still run the risk of burning it out, this is precisely why LED's have voltage ratings to start with! You can't just feed them any voltage and make sure that just the current is fine. So if your battery went up to 14.4v and you set the buck converter before at 12.6v battery input to 3.5v output for LED's and 30mA. Then when the battery voltage goes up from the alternator the output will go past 3.5v (most likely past 4v). Which will lead to the LED not consuming it's normal 0.1w, but instead wthin 0.13-0.15w. So while it isn't terrible, usually it will shorten their life significantly to be running 50% more power through them than they are rated for.

what would you do if you had an array of these LEDs? for example if you had 10 white LEDs and you wanted to PWM each one individually so they could all be at their own brightnesses, would you need a regulator per LED? surely if they were all using the same regulator then the load would change depending on how many were on or off.

Hi, could i add a mosfet to the wires going to the 1 watt led as i need to feed the owtput from a pwm Board to make the led 1.5 kz with a duty cycle of on 7 off 1 , this is for a 1970's british army infrared Intrusion alarm set called IRIS i was given which only had 1 ir transmitter , i have made the system work with the pwm board and a 10 mm 850 nm led With resistor but will use 1 watt 940 nm led's To make 4 ir transmitters which need more current than the pwm board's can take.

Hi Julian, I am new to this LED. I am trying to learn. I have some of the small 3W LED which you have shown in your video. I like to use them for a lamp to convert to 12V so I can plug into 110V wall outlet. What kind of voltage current regulator would I need to use to support the LED. I like to use anywhere from 1 to 3 LED for the lamp. Thank you John

HI, Great video. I have a question, what if you 9 leds in series/ 3 x 3 @ 900mA and one led in one series went out causing that entire 3 led in series to stop work, wont that overpower the other 6 @900mA. Thanks

i just had a look and they have some really great stuff, i think i will save that seller for later! but as for the drivers, i need them small because i am going to have a 24 grid of LEDs and the drivers can't take up too much room so i was thinking of designing my own based on the PT4115 driver, its very small and looks like it can handle up to 3 watts

If we use for example 6*0.5w resistors (of course with the right total resistance) to power up a 3w led, will it then be sensitive to regulating voltage, f.e between 12v-14v?

Hi Julian Great videos but the way! I have a few of this exact regulator, could I use it safely as a sub c batterie charger. I need to charge them individually so I have set the voltage to 2.3 volts and the current at 450 mA as they are 5000mA cells. Is that OK? And when they reach capacitie will the converter stop charging? The light is red while charging, will it turn green when they are full? Thx again! Adam

thanks for the reply, I know there are LED drivers out there that can control an array of LEDs, but i haven't seen anything for 1W LEDs, but thanks for the answer, i was thinking i would probably have to use individual drivers,

Hi Julian another great tutorial, I am about to purchase one of these or similar modules but have noticed sometimes they are a blue board, or a red board. are they same? just different coloured boards? Thanks.... John :)

how would i run 120 - 3watt LEDS on one power supply connected to the wall ?

The 1 watt LEDs may look fine, but running them without a heat sink for long periods of time will shorten their lives. They will a least reach their 70% lumen maintenance a lot faster. Depending on the manufacturer, you can get a sustained decrease in output of 10% or more in less then 6 months. Keeping the junction temp low will also increase the lumen output. you can just barely get away with using a star alu PCB for a 1 watt LED.