20W multi-die single chip spotlight/headlight

[Frank88]

I need your help for some parts of this project. I was browsing Ebay few weeks ago and found a 20 watt led. Well I bought it… It's a Led array, made of 5 lines of 4 led in series (1 watt each I guess) it's rated 13.8-16 Volts. I Thought I could make a Spotlight for my quad handlebars (KFX 450r '08) or make a flashlight out of it(im nort sure yet). When it arrived, I tried it with a car battery for few second just to see and OMG !!! that thing is nasty for the eyes ! and produce quite a lot of heat so for my project I ordered a 40x40mm heatsink (for motherboards) and a 40mm fan and once received, put it all together and made some test to see if it was sucking enough heat to prevent the led from burning, I checked the led with my welding helmet to see any change of light over time, well it's a success, after 5 minutes of continuous power, cut down the power and touched everywhere… COLD so its prefect in term of heatsinking.

But the light itself is floody, too much floody (but powerfull !) so now im searching for a suited reflector but found nothing on DX or ebay that could be used. Im searching for something not too much expensive and that would produce a narrower beam that could be more usefull for driving (around 45 degrees ?)

The Led is rated 1000-1500 lumens and stated Foward voltage is 15-18 V right now but when I bought mine I remember seeing 13.8 - 18 V and like said before works fine on my old car battery sitting at around 13.3 volts

The total size of the led is 40x32 mm and the led array(yellow) is 15x8mm

Note : I asked seller about hotlinking his image and it's okay, not asked for the others, removed

The only option I see right now is using a old Garrity 6Volt spotlight
Any idea, input or anything ? lovecpf

 

[snarfer]

It's probably cold because you're not running it at anything close to full power. You have to measure the current in order to tell what is going on with it.

If the output is sufficient for you, then I guess it doesn't matter. But I would suggest at least a constant current driver.

 

[Mike Painter]

You might see if you can find a Fresnel lens to focus it. If they can put a kerosene flame out 20 miles they should be able to focus what you have.

 

[alpg88]

idk, man.
the led is cold cuz you don't drive it at max or close to max amps.
it has no dome, it is odd shape, hard to say what reflector would work right, unless you wanna go reflector less, for pure flood.
now, having done a few lanterns mods, i'd say the donor is total garbage, it isn't worth modding it. you'll need to find a way to hold the battery, cuz originally, bezel\reflector is holding it, but once you cut out original bulb, what will hold the battery? at least find the body worth modding, i looked for it for a while, finally found one that is waterproof, and more rugged than others, wasn't easy, I'll tell you. it is dorcy rubberized lantern. i bought 5, still have 2 originals left.
but don't let my words discourage you, go ahead build it, as you build you'll learn, as i say with any of my builds gone wrong, i didn't fail, i found the way how not to build a light. nothing will teach you better than your own mistakes, i mod lights for pbly 10 years, a i still make mistakes. next one will always be better.

oh, wait you cant use 6v battery, you need more than 2x as much, so you'll have to use rechargeables, in the space taken by 6v bat. you can fit around 20 aa's, get 14 cells, wire them in series, since you don't need to get them out, problem of holding batteries is solved, tape them and hot glue them in there, charge them inside.
that led needs 1,4 amps, nimh aa's are perfectly capable of that.

 

[alpg88]

You might see if you can find a Fresnel lens to focus it. If they can put a kerosene flame out 20 miles they should be able to focus what you have.

:twothumbs i agree, it worth a try

 

[Frank88]

Well first of all sorry for my bad english, I know it's a little bit hard to get and I did my tests way too quicker, played with it a few minutes ago and when in operation it's getting more and more hot, i touched it all the way of the test and after around 3 minutes it reaches max working temperature(at the ambiant air temperature i was) I let it run few minutes and after 10 minutes i checked again and still about the same temperature(by touch no thermometer, under but near the melting point of hot glue). As for the voltage the battery is plugged on a 750mA charger for car battery(slow charge) to keep it more constant for the test i made, Voltage is stable @ 13.10V with the led on. I then mesured the Amps and got 1.58A.

If I choose this led as a flashlight, I will of course not use the 6 volts battery ! I was more thinking into 4 18650 protected battery in serie (around 16.8V i think?? )
If i manage to find a way to fit it with something solid with a smaller lens than the spotlight on the picture, It will be direct driven (with a 15 amps switch) on the quad battery.

Are there any way to make a reflector by myself with chrome paint or something ?
Im not planning in putting the light pure flood because its almost 150 degres viewing angle (lot of useless side light) if i could get this light concentrated somehow into around 45 degrees or so would be fine.

 

[alpg88]

don't worry about your English, i understand you fine.
I'm still a bit confused how you get 1,58 amps out of 750ma power supply, but anyway, you'll see real results when you connect your led to a battery pack that you will be using in the light.
as for battery options 4x18650 are great option however there are complications when charging li ion pack, you need special charger, otherwise you damage batteries or worst. unless you charge them separately. imo better safer and cheaper option would be nimh, either aa or sub c, itis a lot easier to charge nimh batt. pack, those cells are also more forgiving, once i was building a light for 6v battery, but later found out alkaline battery drops v too much, so i had to put 10 sub c cells into gutted 6v battery housing, there is room there for 14 cells, the trick is arrangement, you put 3 diagonal, than 2 on each side, 2 levels, 7 in each.
as for reflector, honestly i have no idea how to make one without spending a lot of time money, i mean the one that is right geometry and surface, there was an advice to try Fresnel lens, you should try it, those lens aren't expensive, or try reflector that lantern originally has, just cut out the hole right size, try it, just don't try wiping reflectors for any reason, either blow off the dust..ect away or wash it, but don't touch it.
also it is a very good idea to use a driver, but i never seen a driver for 13-16v-1,4 amps, i hope may be someone will direct you in a right way. in case you don't find one, than use resistor, cuz you don't wanna blow the led, and ruin your entire project.
here is a useful link on resistors, and wiring http://wolfstone.halloweenhost.com/L...eringLEDs.html

 

[circa]

What type of chrome paint? I had some for a non flashlight related project, was 'shiney' but hardly chrome/mirror like. Would work great for a Incan but not led.

 

[Frank88]

I'm still a bit confused how you get 1,58 amps out of 750ma power supply, but anyway, you'll see real results when you connect your led to a battery pack that you will be using in the light.

Thanks for the answer !
Oh maybee it wasn't clear, the 750mA charger is plugged to the 12 car battery and im feeding the led with the battery, not the charger, the charger is made to keep stored battery charged (auto idle on charger) it's just that if don't put the charger, the voltage drops over time and to get a more precise value of amps i just decided to let it stay on the battery to keep it more stable (which works).

As for the cells im curently waiting a charger and 4 18650 protected 2400 mah battery[my first set of 18650] and i don't really care to have to charge them seperatly, in batch of 2. It's not really an issue if i go for the flashlight way but i would really like to put it on my Quad.

Im not an electrical engineer but I don't think I will fry the led while direct driving it. Such driver exist, the ebay seller sells AC drivers for this led but im not planning to use it stationary.

P.S. : Your link redirect me into a horror film search engine

What type of chrome paint? I had some for a non flashlight related project, was 'shiney' but hardly chrome/mirror like. Would work great for a Incan but not led.

I never bought chrome paint, I just thought it could be reflective enough to coat something (not mirror like real chrome of course but something like OP style). The car below has a professional chrome paint but is not real chrome so that's why i was thinking it was possible...

EDIT : Chrome car image hotlinked removed, Search Chrome BMW on google if you wanna see it

 

[spc]

Ive seen that paint in person, its not bad at all- closest I have seen to chrome without being chromed. 50 cent had a lamborghini painted with it also- it was nice.. Its from Alsa Corp. You can even get it in a spray can now. I bet it would work great on a custom made reflector.- alot better than metal tape or foil.. They have videos on their page www.alsacorp.com.

 

[alpg88]

P.S. : Your link redirect me into a horror film search engine

wow, it worked fine before.
fixed.
http://wolfstone.halloweenhost.com/Lighting/litlpo_PoweringLEDs.html

 

[circa]

Damn. 40$ for the chrome paint, 115$ for the kit.
Maybe pheonix reflectors could help If you can't find anything to use as a reflector. Would be a very interesting light.

 

[spencer]

I believe that these LED's are typically quite low efficiency. I think around 40 lumens per watt. You can get a Phlatlight SST-90 that has about twice that efficiency at twenty watts. That means twice the light with the same amount of power. Another advantage to using the SST-90 is that the light source is much smaller so you don't need as big a reflector to focus it compared to the LED that you have purchased.

 

[Frank88]

I didn't know the existence of the Luminus sst-90 before a week ago, I read alot here and elsewhere since. But still the sst-90 is hard to find (didn't really searched tho) and more expensive...

Im gonna try this week want i can do with the spotlight reflector.

 

[guiri]

But still the sst-90 is hard to find

Not really... http://www.4sevens.com/advanced_search_result.php?keywords=sst-90&x=0&y=0

 

[Frank88]

Ok ok i didn't did my homeworks maybee im too addicted to the bay.

Anyway if it could helps, I have acces to a Lathe(i dont know if its the right word but a machine tool which make the work turn) and aluminium tubing and im alot very good at polishing until chrome-like finnish...

I just did few hours with the turning machine tool so i don't know all the possibiliy but i dont see how to get a decent cone.

Im in the Final exams at the University so im kinda busy right now, I will post actual picture of the thing and i will test the cheapo spotlight reflector.

 

[guiri]

Lathe is correct and don't worry about not knowing about the SST's. That's what this forum is for

ALso, your english is fine. Much better than my french

 

[bstrickler]

There is also this for SST/SSR-90/50:

http://www.cpfmarketplace.com/mp/showthread.php?t=216386

~Brian

 

[easilyled]

Why don't you try to get your money back for that led on ebay and buy an SST-90 Premium bin from photonfanatic on the marketplace instead?

This will be far better for your modding. :thumbsup:

 

[saabluster]

Frank88 you need to remove that hot-linked image.