Introduction: LED With Cooler Heat Sink

Picture of LED With Cooler Heat Sink

LEDs are cool! But they tend to get hot and start flickering! We usually put Heat Sinks salvaged from old computers which can do a decent job, but they are not enough for High Power LEDs. So, I tried to sandwich a peltier chip between the computer heat sink and a 100 W LED module, and it worked!

There was something very interesting which happened, as I had tried using all the 12V adapters in series at home to power the circuit (including wi-fi and few other devices, and my folks were not very happy about it! ). After getting too hot, the peltier chip was sending back-emf which was stopping the fan. The trick here is to keep the power supply for peltier, LED and fan separate.

Here is my instructable for the project!

Step 1: Stuff You Need for This

Picture of Stuff You Need for This

1. LED module, I used a 100W one.

2. A heatsink and fan from an old computer.

3. Peltier chip, I used one with max. power rating of 92W.

4. Thermal paste

5. Wires

6. Clips for putting everything together

Step 2: Prepare the Heatsink Assembly

Picture of Prepare the Heatsink Assembly

1.Put some Thermal paste on the heatsink and apply it with a metal strip evenly.

2. Repeat the process on all the surfaces, on both sides of the peltier and the metallic side of the LED module.

3. Place the LED on top of the cold side of peltier, and hot side on the heatsink in a way that peltier is sandwiched.

Step 3: Attach the Fan to Heatsink Assembly

Picture of Attach the Fan to Heatsink Assembly

1. Attach the fan to this assembly by clips or any other way possible.

2. Connect it to different power sources

Since I have made one already, and I am too lazy to solder all these together. I am just lighting my old one for the demo!


Budweiser143 (author)2015-11-18

Would it be possible for you to add some images of how your using thhis LED, and its brightness?

Abhindas (author)Budweiser1432015-11-24

I currently don't have a Lux meter, but as soon as I get my hands on one, I ll post it here. It was bright enough to not look straight into it.

martonthenagy (author)Abhindas2016-02-11

Use any digital camera that has ISO + Aperture settings, and Shutter speed readings.

It is not as good as a commercial product, but much better than nothing.

Yonatan24 (author)Budweiser1432015-11-24

I think I can tell you about how bright it is:

INCREDIBLY BRIGHT, I used 10X 10W LED's to make my "SpectrumLED- Variable Spectrum LED light" (picture below) Having 10X 10W are more efficient than one 100W LED

It can light up my whole room easily, Which might not mean anything to you, But it is just incredibly bright. My camera auto adjusts the brightness so it doesn't look as bright as it really is, But it is blindingly bright!

By the way I'm also uploading a full step-by-step Instructable of how to make "SpectrumLED" in a couple of days, In case you're interested...

kennykaos (author)2015-12-25

I am trying to design a fan-less 100Watt led design for outdoor. Would a peltier be more reliable than a fan? I have a heat-sink with 4 direct contact heat-pipes on the way. I am going to back the voltage down until it will run cool without a fan (just heat sink) to see what it will do.12 hours on 12 off, I think the fan would be the weakest link, if I had to use one. I am thinking the peltier might be more reliable than a fan with no moving parts. I would like to use it between the chip and heat-sink.

on the way.

notingkool (author)kennykaos2016-01-03

A fan increase enormously the efficience of a heatsink, and the alternatives aren't as practical. The disadvantages of a fan are noise and dust and moisture into the heatsink. But they consume very little energy.

There are fanless heatsinks but they are quite big for 100w.

btw, LEDs lose efficience when heat up ( less lm/W), the higher the junction temperature the less light they produce.

Abhindas (author)kennykaos2015-12-26

Peltier just transfers heat from one side to other, its good for keeping the temperature lower than what fan can achieve, keep me posted with the development.

steven4872 (author)2015-10-28

"There was something very interesting which happened, as I had tried using all the 12V adapters in series at home to power the circuit (including wi-fi and few other devices, and my folks were not very happy about it! ). After getting too hot, the peltier chip was sending back-emf which was stopping the fan. The trick here is to keep the power supply for peltier, LED and fan separate."

Your lamp assembly draws about 200 watts. Wi-fi and a few other devices probably add at a minimum 30 additional watts. Most 12 volt adapter are not rated for that kind of power. The most powerful power supply I have is a 90 watt 20V power supply that powers my laptop. Most of the rest are typically rated at less than 20 watts.

You were probably overloading your power supply. Frequently overloading a power supply will cause it to fail. However if it doesn't fail it could also cause the power supply to generate a lot of EMF noise and voltage regulation problems,. Peltier chip running on stable DC power will not cause EMF. If you replaced your power supplies with one rated at the correct voltage, power, and current ratting you probably would not have had the EMF issue.

Abhindas (author)steven48722015-10-29

The total number of power supplies I used were five, three 12 V and two 20V supplies from laptops. For LED I used one Laptop and one 12V supply in series. For the peltier I used a similar configuration. And another 12V for the fan. This was after I tried putting everything in series and the fan would stop after a while and LED would also stop.

ironsmiter (author)Abhindas2015-10-29

the concept is awesome, and practical. even commercially viable.

the execution and planning, a bit more on the what NOT to do side.

32 volts into the led? and another 32 for the peltier(which are almost always 12 volt devices)? all likely with a shared ground(formerly fumctional power strip?)

interesting experiment, but a basic electrical circuit refresher is in order.

unless your devices were rated for and required those voltages and even then, each series supply would cap out at the lowest rating of the pair(12v1A plus 20v2A is equal to or less than a 32v1A supply).

kinda surprised you didn't fry your peltier junction, burn our some of the leds, and most surprising that you didn't blow a breaker or ground-fault switch with the power wiring hijinx


Abhindas (author)ironsmiter2015-10-29

Thanks a lot for pointing that out, to be honest, this is probably the first time I am trying something electrical or electronics. I ll make sure of using a proper power supply for further experiments.

steven4872 (author)Abhindas2015-10-29

Your led is 32 to 34 volts at 3.5amps. You powered thay with 20V and 12 power supply in series. It is generally not a good idea to wire two power supplies in series. If one power supply cannot supply the needed surrent its voltage may drop and more of the load may go to the other power supply. This might cause voltage oscillations. Your luckey you din'tblow the LED and power supplies. If you have to use two power supplies in series make sure the current output rating of each power supply exceeds the current the LED needs.

Yonatan24 (author)steven48722015-11-24

I've heard that putting them in series is okay and putting them in parallel is bad, I guess I was wrong and right

Abhindas (author)steven48722015-10-30

Thanks a lot, I am never going to repeat adding power sources to get a higher voltage.

steven4872 (author)ironsmiter2015-10-29

12V Peltier are common because many portable coolers are designed to plug into car 12VDC systems. Peltier arrays are available in voltages from as little as one volt to many volts. It all depends on how the individual peltiers are wired together inside the device. I have seen a 60W Peltier rated at 15V. For a 100 watt device 32 volts is a reasonable voltage.

While Peltier arays are quite small the high current needed results in large power supplies and thick wires. Using high voltage Peltiers can help reduce the size of the power supply and wires by reducing the needed current.

The same goes for the LED he used. If it was one led it would need about 3.5V and about 28 amps of current and very thick wires. But if you wire a bunch of smaller LEDS in a sereies parallel arrangement and then coat all of them with a single piece of phosphor you can get 32V requirement that would only need 3 amps and thinner wires..

georgerd made it! (author)2015-11-03

Here is my version. Very bright and lighter than a 3 D cell Maglite

Yonatan24 (author)georgerd2015-11-24

Wow, That is one huge lens!

rickyeatough (author)2015-11-01


Im halfway through making one of these for use in another led project. Ive already got the 100w led but it isnt bright enough..
Do you know anyplace you can get a 200w led/driver? On ebay its around 100£ including the postage!

RanT1 (author)rickyeatough2015-11-04

Are you certain it's really a 100W LED? There's a lot of complaining online from people who buy cheap no-name LEDs from ebay and other mail-order sellers that turn out be as little as half as powerful as claimed. E.g., one guy bought "10W" LEDs and discovered that they drew about 450mA at 11V. Increasing to 12V nearly doubled the current, but with no visible increase in light. So, yeah, it was 10W, but half that was utterly wasted heat.

Some of the ones I've bought cheap don't seem to be as bright as I expected, but I don't have a precise way to measure absolute light levels, so I don't know whether I'm having the same problem, or just have unrealistic expectations.

Is there another DIYer near you who might have another 100W LED for comparison? Maybe you just need to get one that meets spec.

Yonatan24 (author)RanT12015-11-24

You are probably right, There are two different kinds of measurements:

Watts (VoltXamp)

Chinese Watts (what you buy on eBay)

You get the point...

That isn't always true, I bought 10W LED's from eBay and I measured them and they were ~12W, WIN!

qqqqqqqqqqqqqqqqq (author)2015-11-03

Wouldn't it be easier, cheaper and more efficient to use water cooling on your LED?

Water cooling needs a lot more space to start with, with peltier it can have a smaller form.

Yonatan24 (author)Abhindas2015-11-24

Well, Using a peltier will probably make you need a power supply that can give at least 15AMPS, 100WLED+~5AMPpeltier= Expensive power supply...

techlv (author)2015-11-03

Nice! I use a 10W LED chip+cooler as a lamp with an Arduino nano. PWM controls brightness through a N-channel logic level gate FET and can work with any infrared remote control.

Abhindas (author)techlv2015-11-24

Cool, please do post some pictures!

Consider My Solution (author)2015-11-03

Simple, basic, electronics training will give you the tools you need to perform calculations for this kind of project. The calculations for power required are not complicated, but if you don't do them at the beginning, then you will have the kind of results that you have with this project.

A peltier device is VERY inefficient. You ended up wasting so much in this project, only because you didn't do the electronics planning at the beginning.

I know you said you were just beginning, but begin in the right way and educate yourself in electronics. You won't be disappointed, and with your ideas you will have much success.

Thanks a lot Tx, I would do the same.

david.roseman (author)2015-11-03

Where is any info? What voltage/current do I need? Do I need to limit the current? Why use a TEC unit? Wouldn't a fan be fine? Telling me to connect it to different power sources is...well, deadly.

Abhindas (author)david.roseman2015-11-24

Let me get my hands on a good power supply and I ll post all the answers. The heat sink and fan arrangement I was using, would make the LED chips flicker in a few minutes, with peltier, the light was consistent. I need to do more experiments with the whole system.

TravisM18 (author)2015-11-03

I think if it was cold enough outside you could use the themo electric device to run your led.

Abhindas (author)TravisM182015-11-24

Interesting, I might try that out!

Phil_S (author)2015-11-03

Watch your eyesight with LED's that powerful - even lower powered devices will give you an after-image that will last for hours - eventually, it might not go away.

As commented by others, messing about with unsuitable power supplies isn't a great idea - you need to be looking at some hefty devices, with plenty of protection

Abhindas (author)Phil_S2015-11-24

Thanks a lot Phil_S for the suggestion, I agree that it was a potentially dangerous thing to do at home.

Yonatan24 (author)2015-11-03

What is the "emf" that you said the peltier was sending back?

Abhindas (author)Yonatan242015-11-24

After getting too hot, the fan (which was in series with my fan, and hacked together power supply) would stop, I assumed that it would be the back emf by the peltier.

Budweiser143 (author)2015-11-18

Would it be possible for you to add some images of how your using thhis LED, and its brightness?

ericanto (author)2015-11-04

Nice 'able but I don't really understand the use of the peletier kit (maybe for the fun ?). Peletier Kit only have an efficiency of about 0.6, so you will need an even bigger heatsink than for the LED alone or it will only work for a limited time.

If you use a 100W peletier kit for a 100W LED, you will divide your global efficiency by at least 2.

If you really need that much light without increasing the size or the quality of your heatsink, you should maybe consider using a high-pressure sodium lamp, a HID lamp or a fluorescent lamp.

mattcintosh (author)2015-11-03

I just picked up a Dell C764N Power supply from my local parts supplier. I think it for a small form computer. The thing puts out 12V at an amazing 18 Amp. It looks to be remote switched as well. I gotta find a project for it.

darklylit (author)2015-11-03

There's a great DIY project here that is very specific about how to wire it with a single power source:

MrTale95. made it! (author)2015-10-31

i maded onice on 12V batery lamp 100W LED= 1000W clasisc light ;)

Yonatan24 (author)MrTale95.2015-11-03

What battery do you have in the back? Is it a lead-acid battery?

Avaruushirvi (author)2015-11-01

Well... You have in first test some kind problem, course THAT CPU cooler with fan can haddle that 100W LED with out any problem!

How you think it can haddle this your new saaituation?
LED: 100W
Peltier: "100W"

And your PSU?
For LED i quess 30-35V and 3A
Fan 12V 100mA?
Peltier something like 10-15V and 10-6.67A

And that LED is possibly something like MAX 60-70lm/W

tutdude98 (author)Avaruushirvi2015-11-01

For battery powered i would probably go with cpu heatsink with heatpipes without peltier (something like DIYperks did)

jim47 (author)2015-10-29

How to you control the current to the LED?

You said " worked!" How to you quantify that? How is the LED temp different than using the heat sink and a fan (with LED powered at the same current)?

What is the total watts consumed per per 100 lumens?

Abhindas (author)jim472015-10-29

I used a kitchen thermometer to measure the temperature of the LED light, and my LED used to flicker after operating for more than a minute with the computer heat sink, I could see that it start flickering after 32 Degree Celsius. So if some way, the temperature can be lowered (that's why the peltier!) the LED module would operate without any disruptions.

When I used this setup, It worked without any flicker for long.

I haven't calculated total watts consumed/100 Lumens but it is definitely higher as we are powering the peltier as well! This can be used where a smaller size of the LED is required.

Saiyam (author)2015-10-29

Looks pretty good!

Abhindas (author)Saiyam2015-10-29


cweller3 (author)2015-10-29


Abhindas (author)cweller32015-10-29

The rating is around 8.5K but I wasn't supplying more than 77W. I need to get a device to measure the exact intensity.

tomatoskins (author)2015-10-28

This is so cool! Where do you get your LEDs?

About This Instructable




Bio: Abhinav Das is an innovator, based out of Delhi. His previous startup, Evomo which is short for Evolving Mobility was incubated at NID Ahmedabad where ... More »
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