# one more 100W LED cheap flashlight --- Help



## StrikerofDeath (Aug 25, 2014)

*100W LED cheap flashlight*

Hi!
i will start make one cheap flashlight (just for fun) with 100w led chip.
I already have the LED and reflector with a 44mm lens, but the problem is focus of light.






at small distance gives a lot of light, but the range is very short. 

in this project is possible to see the LED operation 
http://www.candlepowerforums.com/vb...oder-10000LM&p=4118601&viewfull=1#post4118601

how can I increase the range of light?


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## Conte (Aug 25, 2014)

You would need a big kickass reflector for one.
It's a very large emitter that's probably designed to flood, so it will be difficult to get it the throw.

There might be some form of lenses that can, I don't know much about lenser style lights. 

Look are the bright side, you got short range covered, won't even need to aim it.


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## LEDPunisher (Aug 25, 2014)

This would be the kind of LED that I want to put inside my Modded Coleman lantern. As-is, I'm stuck with a 15W 12V LED, but it is very bright.

I would look into a reflector cone, plenty of places on the net to find them for dirt cheap.


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## StrikerofDeath (Aug 27, 2014)

thanks for replies!
yes, at short range don't need to aim it!

I don't know much about light, lenses and reflectors, but I'm thinking make one more reflector in cone to put after the current 44mm lens. will be a good idea?


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## LEDPunisher (Aug 28, 2014)

StrikerofDeath said:


> thanks for replies!
> yes, at short range don't need to aim it!
> 
> I don't know much about light, lenses and reflectors, but I'm thinking make one more reflector in cone to put after the current 44mm lens. will be a good idea?





You might be better off just getting a reflector that can go right atop the LED packaging, rather than using a lens and then a reflector.


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## JP Labs (Sep 3, 2014)

One lens optics design I have seen applied for LED throw is the Huygens. Here's a really neat build by Walterk, where I first learned of the idea to apply this design as an LED projector. 

For the 2nd, big lens, you could use a cheaper Fresnel. 

http://www.candlepowerforums.com/vb/showthread.php?301559-Huygens-Ultimate-1-800-000-candela-Led-light


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## StrikerofDeath (Sep 4, 2014)

first version of flashlight:










missing the reflector yet, but results are not very bad :thumbsup:


this project is very good!
Fresnel is identical to a loupe, right?

I think will try a simple magnifier like this:

http://www.ebay.com/itm/LARGE-HAND-...y_VisionGlasses_Lenses_SM&hash=item1e913735d6


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## Conte (Sep 4, 2014)

Hah, what did you make e body out of?


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## JP Labs (Sep 4, 2014)

What a cool looking light!

I think a Magnifier like you showed would work, sure. Play with the distances of the lenses for focus if you don't like the initial beam.

A Fresnel lens is not really like a Loupe, no. It is thin and flat, often plastic, with multiple small circular ridges on one side of the surface. These ridges are prisms which bend light, so the effect is similar to that of a thicker glass lens, accurate. Advantages for Fresnel are low cost for large sizes, and you can cut them to the size needed. Ideally, you would want the final lens to be big enough to capture the entire beam of light from the first lens. Smaller will work, it will just catch less of the light. 

Here's a pretty good picture of how it works:
http://www.teara.govt.nz/en/diagram/6675/fresnel-lens


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## StrikerofDeath (Sep 5, 2014)

Conte said:


> Hah, what did you make e body out of?


PVC pipe.


JP Labs said:


> What a cool looking light!
> 
> I think a Magnifier like you showed would work, sure. Play with the distances of the lenses for focus if you don't like the initial beam.
> 
> ...



thanks for explain!
the fresnel lens are plastic, doesn't go melt down?

I will try find something at local shops.


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## JP Labs (Sep 11, 2014)

The light is pretty diffuse at the Fresnel lens, not concentrated, if focused right. So, any reasonable bulb should not melt it. 

Old rear projection TVs, and overhead projectors, are two cheap or free sources for Fresnel lenses. My bicycle headlight uses a 6" circle cut from an overhead projector as a lens on the reflector. Not set up for long throw, but gives a nice pattern for biking.


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## StrikerofDeath (Sep 12, 2014)

I will try it 
I saw this video too:
http://youtu.be/ilRNQD3w75Y

today I made the first repair, the switch does not endured a drop


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## Augbug (Sep 21, 2014)

I saw the same video and am going in the same direction, the tests I've done outside with the fresnel lens have been amazing, really incredible range and focus.


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## StrikerofDeath (Oct 9, 2014)

Hi!
I already have the lens, but was no time to make the body for it and test. 
at first looks like it will work!


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## JP Labs (Oct 11, 2014)

Perfect! 

You will probably want to play with both lens positions to find best focus.


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## Sigrm (Apr 14, 2015)

How did this old story end? Would love to see how well you got the fresnel to work! Doing a similar build myself


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## StrikerofDeath (Apr 14, 2015)

not over yet, I have used this light to camp.
when I have time, I'll redo it again with some features (including fresnel lens with fittings)


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## Flyingdrums (Apr 19, 2015)

What are you using for power?


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## StrikerofDeath (Dec 31, 2015)

Flyingdrums said:


> What are you using for power?



the flashlight is powered by 5000mAh 22.2V lipo, about one hour at full power
I want to convert to 18650 cell's


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