100W LED - Flashlight




Introduction: 100W LED - Flashlight

About: I'm an educated engineer, with a drive for learning new stuff! I hope to make many instructables in the future to inspire and help others to be creative and innovative! Not all projects are either arduino o...

Welcome back!

And yes.. A 100W LED is alot... It is approximately 9000 Lumen. A car on high beam produces about 4000.

And that sums up why I made this. It's awesome!

Let's get to it.

Step 1: The Idea

I have worked with some 10W LEDs in the past and they produced a lot of heat. Therefor I wanted to have a great cooling system that could cool down the LED.

The picture is more or less what I came up with.
This should somehow continuously cool down the led.

Step 2: The Electronics

Step 3: 3D Printing

Because why not!?

While I was making the 3D model i saw online some other projects similar to this where they used PVC tubing, and was about to do that instead... But hey when I got an excuse to 3D print.. I 3D print!

Step 4: Assembly

Now that the 3D printed model is printed to fit all the components it was very easy to screw everything to place.

I gradually soldered the electronics while I worked my way back to the end compartment with the batteries.

The battery was made by 4 old laptop batteri cells (18650). If you know how this process works you can see I have tested these and marked the capacity on the cells. this helped me to find 4 more or less similar cells.
I can definitely recommend to scavenge these batteries whenever possible. You never know when to use them!

Step 5: Test!

I made mine without a BMS system. this means i need to charge the battery on a battery charger as you can se here. If you just want a power input to charge the cell a 4s BMS is recommended.

Like this: https://www.ebay.com/itm/1S-2S-4S-3S-5S-6S-BMS-PCB...

I will try to get some better pictures for you so you can se really how much it lights up. It's a lot....

I hope you enjoyed my instructable and i hope you want to make one of your own!
If you liked this projects dont forget to throw a little vote in my direction. It definitely helps me out and it helps me to know what you want to see more of nex time!

See you next time!

2 People Made This Project!


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82 Discussions

Neat enclosure, but would it cool enough in air?
(versus water, which is much more dense and cools better)


can u please put the link for that flashlight?

Thanks man!

If i could print in alu i would ;)

Now this is a 3-D print that uses plastic printing in a PRACTICAL and EFFICIENT way! Not using tons of plastic!

3 cheers to an impressive design!!

Not accounting for the fan's consumption or power losses inside the boost converter, a 4s battery pack is going to need to supply 6 - 7.5 amps at 100W, depending on its level of charge. Most 18650s are only rated for a maximum of 4~5 amps. Ive never seen a laptop battery 18650 over 2400mah and 5 amp maximum disharge rating, and I have over 100 cells out of laptops in my toolchest. Add to that the lack of protection circuitry, and it is a bomb waiting to go off.

The highest capacity 18650s currently available are only 3000-3500mah, and this mah rating is at a fraction of an amp. Storage capacity severely degrades at high discharge rates. It is physically impossible for those 4 18650 cells to supply 100 watts to the LED for 30 minutes with current technology. Please dont mess around with lithium ion batteries unless you really understand what youre doing.

Here is mine. http://www.candlepowerforums.com/vb/showthread.php?406385-My-DIY-100W-LED-Monster

5 replies

i read your post on candlepower forum but i cannot seem to be able to get into it again. I thought of a very important safety issue that perhaps you did not think of. my email is john.conrad873 @ gmail.com. please contact me and i will explain

yep!!! i give it 20 minutes approx. 2.5A-H batteries 2.5/7*60 = 21 mins and that's without taking the Boost converter losses into consideration

Also, in the circuit diagram, you need to move the power switch from between the boost converter and LED to being between the battery and boost converter. In your current layout, the boost converter will run even when the power is off. This will destroy the batteries since they dont have a low voltage cutoff, and the datasheet expressly states that you should never run the boost converter without a load.

Thank you so much for the concern i have been using these 18650 for some time now. as i hear, you also have done the whole scavenging cells from laptops procedure. :-)
You are absolutely correct in you comment and it is definitely a mistake not to have some sort of safety lige a BMS with current cutoff.
Thank you so much for the input and i hope many others will read your comment befor making one similar.
Have a great day :-)

100% correct.

If we want to employ Lithium battery cells we really need to know what we are doing. These cells have been known to explode or burst into extremely hot flames if misused.

I have seen other builds using this 100 w LED. Of course it is really bright and could be useful. However, from a practical standpoint, the fact that one is limited to a half hour duty cycle. There are a few things I would like to add to make this more useful.

1) Control how bright it is either by PWM (pulse width modulation) or varying the current with something like this: https://goo.gl/r6QQdg

2) Perhaps double the number of amp hours by increasing the number of batteries or using 32650 sized Lithium Ions.

3) One definitely need some kind of BMS because if your Lithium Ions drop below around I think 3 volts it is more difficult to get them going again...although it can be done.

4) I build portable lasers which require a high current drain. For those I prefer to use IMR lithium ions because they handle the current demand better than others. However, the largest of the IMRs that I know of are 18650s.

7 replies

Yes! yes and yes!
A PWM module would be great :-)
And yes i thought about using 8 batteries instead. i have a lot of them :P
And the BMS is something i am planning to install in the future :-)

hey how come nobody answered this post?

Sorry I have been busy these days.. we have had pre thanksgiving and all sorts of stuff..
That resistor would be able to adjust the power but only down.. and by doing this it would use power to do so. This means that you would have to have a bigger battery and the life time would be poor.

It's my best guess.. :-)

LOL sorry it was a joke. I did not think you would answer it. I thought maybe one of the others on this page might.

The correct way to dim an
LED is by Pulse Width Modulation which applies the same voltage and by extension
the same current but with a different pulse width so the LED brightness does
not change with each pulse and just the eyes do the integration. Dimming by
reducing the current means reducing the LED forward voltage and that changes
the color rendition.

have a good thanksgiving. :-)

You dont need PWM, and you need an external power source to power a PWM circuit. One of the trimpots on the boost converter chip is for limiting current. You can either use a potentiometer screwed to the outside of the case in place of the trimpot, or replace it with a digital potentiometer run by a microcontroller. This will much more effectively dim the LED.

On this exact boost converter used in the instructable, connecting the input ground to output ground will destroy the chip. Similarly, connecting the input and output positive leads will burn it up. So there is no way to run a PWM circuit without a seperate battery pack, unless you build some complicated isolation circuit.
Ive fried two of these exact boost converters in this manner.