# Double Seoul P4 LED light - made of heatsink



## Narajjang (Dec 21, 2006)

Hello, everybody~

I made my bike light with two Seoul P4 LED.

The housing is made of heatsink.

*Here is my LED light database.*

*Light Source:*

2 Seoul P4 LED (bin code: USXPI)
drive current: about 830mAh

*Optics / Reflectors / Lens:*

20mm collimator x 2
6 and 10 degree

*Housing:*

made of heatsink
20 x 45 mm sized heatsink x 6

*Power Source:*

7.4V 6600mAh lithium ion battery
(originally, I use this battery with 6V 10W Halogen light)

*Regulator:*

one 5W 1.2ohm resistor only
didn't use regulator

*Photos:*

1. 20 x 45 mm sized heatsink.









2. Assembly picture









3. Complete picture









4. On handlebar - off









5. On handlebar - on









If the photos are not visible.
Click below link.
https://picasaweb.google.co.kr/uroest/OYJiQJ


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## Hawseman (Jun 1, 2007)

Nice job....very clever, Narajjang. You've got yourself a heck of a <relatively> inexpensive light.

Couple of questions...

That's one monster of a resistor. How is it mounted & how's the heat?

What kind of bar mount is that?


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## Narajjang (Dec 21, 2006)

Hawseman said:


> Nice job....very clever, Narajjang. You've got yourself a heck of a <relatively> inexpensive light.
> 
> Couple of questions...
> 
> ...


Thanks.
The heat of resistor is less than that of LEDs.
So, it can be ignored.
The total heat of light is tolerable because the housing is made of heatsink.

The bar mount is trainer's remote mount.
(Minoura E-RDA 850)


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## Low_Rider (Jan 15, 2004)

Nice design, and thank you for your database entry too! :thumbsup:

I have often wondered about some of the various heat sink extrusions that you can find online, as many have slots and channels milled in to them that may make a very nice housing. It’s just a matter of finding something with the right dimensions! 

Dave.


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## msxtr (Dec 10, 2006)

Wowwwwwwwwwwwwww incredible, I'm like it very, very much!!!!!!!! :thumbsup: 

Where you bought the 10º optic??

Greetings - Saludos

msxtr


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## Narajjang (Dec 21, 2006)

msxtr said:


> Wowwwwwwwwwwwwww incredible, I'm like it very, very much!!!!!!!! :thumbsup:
> 
> Where you bought the 10º optic??
> 
> ...


Thank you very much, msxtr~

I think you made the LED lights much better than me.

I bought 10 degree optic at offline shop.

*) My english is very very bad, too.


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## msxtr (Dec 10, 2006)

Narajjang said:


> Thank you very much, msxtr~
> 
> *I think you made the LED lights much better than me.*
> 
> ...


Thanks to you too 

Now I have see that you use a cygolite led light?? I have a cygolite but this are with hallogen bulb, could you put photos of into your cygolite light, to see how are for into and so I will can copy the desing to do my cygolite with led light 

Thank you very much for all 

Greetings - Saludos

msxtr


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## Narajjang (Dec 21, 2006)

msxtr said:


> Thanks to you too
> 
> Now I have see that you use a cygolite led light?? I have a cygolite but this are with hallogen bulb, could you put photos of into your cygolite light, to see how are for into and so I will can copy the desing to do my cygolite with led light
> 
> ...


Yes, msxtr. I use a cygolite LED light. 
The model name is Hi-Flux 100.
I bought it at the pricepoint.com.
(http://www.pricepoint.com/detail/15...ights/Cygolite-Hi-Flux-100-LED-Bike-Light.htm)

Originally, it is operated with 4 c-sized cell and 3 watt Luxeon LED is uesd.
The brightness of this light is about 7 watt halogen.
(they say this is equivalent of 10 halogen watts...but i don't think so)

So, I change luxeon LED to Seoul P4.
And i use lithium ion battery instead od 4 c-sized cell.
(I use Y-cable to operate this modified cygolite & double P4 light)
Now, the brightness is much improved.
I think it is really equivalent of 10 halogen watts after LED change.

I think the outcasing is same with that of halogen version.
The different point is the LED version has 35mm optic, a heatsink and a resister inside.
I will show you detail photo of cygolite LED light soon.
(When i come back to home at night. This is 10 AM here.) 

Thank you, msxtr.


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## msxtr (Dec 10, 2006)

Narajjang said:


> Yes, msxtr. I use a cygolite LED light.
> The model name is Hi-Flux 100.
> I bought it at the pricepoint.com.
> (http://www.pricepoint.com/detail/15...ights/Cygolite-Hi-Flux-100-LED-Bike-Light.htm)
> ...


Hi, Too you have upgraded the cygolite with a seoul...? you are a freak :thumbsup:

Ok, I will wait your detail photos.

Thank you very much for your help 

Greetings - saludos

msxtr


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## Narajjang (Dec 21, 2006)

msxtr said:


> Hi, Too you have upgraded the cygolite with a seoul...? you are a freak :thumbsup:
> 
> Ok, I will wait your detail photos.
> 
> ...


Hi~msxtr.
These are the photos of my modified cygolite LED light.

1. Overview. The light can be operated in 2 mode(high & low) by remote switch.
Note I changed c-cell battery pack to DC jack









2. The front cover is removed.









3. A plastic ring between optic and LED.
MR 11 halogen lamp is fit for this ring, too.
(I thing this ring is used in halogen version. Isn't it?)









4. The optic. The diameter of this optic is 35mm.(same with MR11 halogen)









5. Now, the plastic ring is removed.
Note I change original luxen 3 watt LED to Seoul P4 LED.









6. The heatsink.
There is no regulator behind the heatsink.
Instead of regulator, a resistor is attached on the front of white plastic part.

















7. Behind the heatsink.









8. Overview of all parts.
The rubber ring is placed between the front cover and the optic.









I hope these photos can be helpful to you, msxtr.
By the way, what's the meaning of 'saludos'?

*) If the photos are not visible.
Click below link.
https://picasaweb.google.co.kr/uroest/Cygolite


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## msxtr (Dec 10, 2006)

*Narajjang* Wowwwwww Yes you have help to me very, very much!!!!!!!!!!

Excellent description and photos :thumbsup:

The O-ring in the halogen version, don't are, the MR-11 bulb go directy of the front cover, but this don't problem I can buy this O-ring without problems. Now I have of think how I do a heatsink of the suitable measures to put into the lamp :idea:

I have a optic called MOBDAR that are exactly of this measure (MR-11, 35mm), I think that are the same that use your lamp...

Saludos are the same of Greetings, but in spanish  That all learn languages of another countries

By the way, with this resistor work to 1a the led? have you measured the current to led?

Greetings - Saludos

msxtr


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## achesalot (Nov 8, 2005)

Narajjang. Awesome chop job on that heatsink to build a cool and economical light.
Have you measured the current you get at the LEDs using the 5W, 1.2 ohm resistor?


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## Narajjang (Dec 21, 2006)

msxtr said:


> *Narajjang* Wowwwwww Yes you have help to me very, very much!!!!!!!!!!
> 
> Excellent description and photos :thumbsup:
> 
> ...


I'm happy my photos are helpful to you.

I didn't measure the current to LED.
(My amperemeter can measure 500mA max)
But I think it doesn't work to 1a to LED.

I use this fomula.
R = (V - Vf) / I
(R=resistor, V=battery voltage, Vf=forward voltage of LED, I=ampere)

I use 7.4 volt lithium ion battery.
But after full charge, Max voltage of this battery is up to 8.4 volt.
Soon it decrease to 8.0 volt.
Vf of USXPI bin LED is 3.25~3.5 volt.
Target amp is 1000mA.(=1.0A)

Put these to above formula.
R = (8.0 - 3.5) / 1.0 = 4.5
But I can't get 4.5 ohm resistor.
So I use 5W 4.7 ohm cement resistor.

*) The original resistor of this light is 5.6 ohm axial resistor. 
But it can't stand heat when connect lithium battery instead of C sized cell)

Put R as 4.7 to above formula.
I = (8.0 - 3.5) / 4.7 = 0.9574...

So, I guess the current to LED is about 950mA.

*) Another way...put all data to this resistor calculator in luxeon homepage.
(http://www.luxeonstar.com/resistor-calculator.php?PHPSESSID=43a1636e4a35e67b1748daae7f0206fc)

The result is similar.
A 4.7ohm 5 watt resistor is needed.
LED current is 950mA

Anyway...I think this resistor eat too much power.
So, I made double P4 LED light.

Saludos, msxtr.


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## Narajjang (Dec 21, 2006)

achesalot said:


> Narajjang. Awesome chop job on that heatsink to build a cool and economical light.
> Have you measured the current you get at the LEDs using the 5W, 1.2 ohm resistor?


Thank you very very much, achesalot.

I didn't measure the current to LED because my amperemeter can measure 500mA max.

I think the current to LED is about 800~850mA.
Because...

1. when using this resistor calculator.
http://www.luxeonstar.com/resistor-calculator.php?PHPSESSID=43a1636e4a35e67b1748daae7f0206fc

Source voltage as 8.0 volt
LED forward voltage (Vf) as 7.0 volt (2 USXPI bin P4 LED in series...3.5 + 3.5 = 7.0) 
LED operating current as 900mA

The results are.. 
need 1.2 ohm 1 watt resistor
Actual LED current is 833mA

2. burning time
when I use my double P4 with 7.4V 4.0AH lithium battery.
The burning time is about 4.2 hours.
4.0 / 4.2 = 0.95...
Considering power-loss by resistor, the current will be about 800mA

Your http://myfwyc.org/bikeled/DIY_LED_Bike_Lighting_Guide.html was very heplful to me.
I am making 2nd double P4 light for helmet as your way.

















Saludos~

*) If the photos are not visible.
Click below link.
http://picasaweb.google.co.kr/uroest/ufUhuK


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## msxtr (Dec 10, 2006)

*Narajjang* Hi, Another double light??  Now I try with Cree leds Q2 or Q5 version, perhaps you get better light with this leds that don't with the seouls...

By the way, buy a good tester (voltimeter-amperimeter), this don't are very expensive and that you could measure well to 1a or more 

By the way (2) how said by your country "saludos?"

Greetings - Saludos

msxtr


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## msxtr (Dec 10, 2006)

Sorry, double post.


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## Narajjang (Dec 21, 2006)

*Hi~ msxtr.*

I heard about Cree's Q2 and Q5.

But I don't know where I can get it.

Here, in South Korea...They don't sell Cree LED both on-line and off-line shop.

Do you know where I can buy Cree LED by on-line?

I want to know on-line shop where can send Cree LED to me by international delivery.

Anyway, I'll buy better tester soon.

And...we say "An Nyung Ha Se Yo" when we say hello to others.

Greetings - An Nyung Ha Se Yo~~Saludos~~

Narajjang


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## achesalot (Nov 8, 2005)

Thanks for the detail Narajjang. Using the resistor is a good tip for cutting the cost of building an LED bike light. The Seoul P4 (U-bin) are just as bright, if not brighter than the Cree Q2 and possibly the Q5 ... and they are usually cheaper and wok well with most Luxeon III optics. I'll agree that Cree has a little tighter binning of their LEDS, and possibly better QC. If you're interest in the Cree Q5 bin:
http://www.dealextreme.com/details.dx/sku.2394

Glad to see you're trying one of the square aluminum tube designs.
- allen


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## Narajjang (Dec 21, 2006)

achesalot said:


> Thanks for the detail Narajjang. Using the resistor is a good tip for cutting the cost of building an LED bike light. The Seoul P4 (U-bin) are just as bright, if not brighter than the Cree Q2 and possibly the Q5 ... and they are usually cheaper and wok well with most Luxeon III optics. I'll agree that Cree has a little tighter binning of their LEDS, and possibly better QC. If you're interest in the Cree Q5 bin:
> http://www.dealextreme.com/details.dx/sku.2394
> 
> Glad to see you're trying one of the square aluminum tube designs.
> - allen


Thank you very much for your opinion, achesalot.

I've never seen Cree Q2 and Q5.
I think the brightness is...Q5 > Q2 = Seoul P4...isn't it?

A question to you...is...
Is dealextreme.com reliable site?...such as quick delivery, payment...ect.

Second question to you, which is the best adhesive between aluminum tubes?

I'll show you your tube design light when I complete them.


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## achesalot (Nov 8, 2005)

Narajjang said:


> Thank you very much for your opinion, achesalot.
> 
> I've never seen Cree Q2 and Q5.
> I think the brightness is...Q5 > Q2 = Seoul P4...isn't it?


 I think that's about right.



Narajjang said:


> A question to you...is...
> Is dealextreme.com reliable site?...such as quick delivery, payment...ect.


 I have not had any problems with DE, and seem to have good reputation.



Narajjang said:


> Second question to you, which is the best adhesive between aluminum tubes?


 TIG Welding  But if you don't have that... I use a product called J-B Weld. There might be other similar metal adhesives available in your part of the world.



Narajjang said:


> I'll show you your tube design light when I complete them.


I always look forward to seeing what everyone builds, whether it's my design, a variation of it, or something totally different... keep up the good work!


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## msxtr (Dec 10, 2006)

*Narajjang* Hi, I see that have response to you achesalot to your questions, nevertheless, I bought my leds in www.dealextreme.com, they have a great service, too you can buy to www.kaidomain.com here I bought too and works perfectly, the pay are in both shops widh paypal and the shippings cost are free to wordwide. Sometimes in www.dealextreme, any led are damaged, but I have write to they and they send to me another that work well.

By the way, that difficult to say "saludos" in your language...  

An Nyung Ha Se Yo 

msxtr


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## Narajjang (Dec 21, 2006)

*Thank you very much for good advise, achesalot and msxtr.*

*achesalot*
I think I should find J-B Weld or other similar metal adhesive.
I hope you keep up good idea for light to me.

*msxtr*
I will visit both dealextreame and kaidomain web site.
I hope you keep up good idea for light to me, too.
saludos~


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## Baulz (Sep 16, 2005)

Very cool light Narajjang. 

Would it work with a 7.2v Nicad battery pack? I assume it would work ok when freshly charged, but not sure once it runs down a bit.


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## Narajjang (Dec 21, 2006)

Baulz said:


> Very cool light Narajjang.
> 
> Would it work with a 7.2v Nicad battery pack? I assume it would work ok when freshly charged, but not sure once it runs down a bit.


*Hi, Baulz. *

I didn't connect my light with Nicad battery.
But when I connect my light with 6V Lead-Acid battery(freshly charged voltage is 7.2 volt), it works well.
(My light didn't uses regulator, so it works well with little lower voltage. but the brightness will decrease little too.)

So, I think it will work well 7.2V Nicad battery.


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## Talkingbelly (Sep 7, 2007)

I don't see the photos, nor can I find the links for the photos.


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## Narajjang (Dec 21, 2006)

Talkingbelly said:


> I don't see the photos, nor can I find the links for the photos.


Sorry, Talkingbelly.
I correct the link.
If it still doesn't work.
click below link.
http://picasaweb.google.co.kr/uroest


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## Talkingbelly (Sep 7, 2007)

Narajjang said:


> Sorry, Talkingbelly.
> I correct the link.
> If it still doesn't work.
> click below link.
> http://picasaweb.google.co.kr/uroest


Thanks Narajjang. I agree with all of the posts; You did a fantastic job!!


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## rubens (May 13, 2007)

Hi Narajjang!
Nice work!
I´m looking for a design to make my light and since i´m new to modding/making lights, i´d like to ask you some questions:

Is your housing made out of heatsink waterproof? You joined them vith what? 
Wich project was easier to do: the heatsink or the achesalot one?
I already have a spot flashlight (fenix l2d rb100) and since i was looking for a flood type light, do you think i would need to change the project?
What are the minimum requirements for the battery? 

sorry about this many questions, but your project really made me want to make one for myself. Thanks


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## Narajjang (Dec 21, 2006)

rubens said:


> Hi Narajjang!
> Nice work!
> I´m looking for a design to make my light and since i´m new to modding/making lights, i´d like to ask you some questions:
> 
> ...


Thanks, rubens.

First of all, I'm sorry about I'm not good at English.

Here are my answers to your questions.

1. Is your housing made out of heatsink waterproof? You joined them vith what?
-> 
There is no problem operating in the rain.
I joined them with screws.
And apply thermal grease on jointing surface before assembling.
After assemble, I apply clear manicure on the jointing line.

2. Wich project was easier to do: the heatsink or the achesalot one?
->
I made both way.
(achesalot's design-> http://forums.mtbr.com/showthread.php?t=336649)
If you can cutting aluminum tube accurately, achsalot's design is easier to do.
If not, heatsink design is easier to do.

When comparing two design,
Advantage of achesalot design is less weight and smaller.
Advantage of heatsink design is...cooling.
When I running both light, achesalot's design is hotter.

3. I already have a spot flashlight (fenix l2d rb100) and since i was looking for a flood type light, do you think i would need to change the project?
->
If you want flood beam, double or triple Seoul P4 light with flood optic is good.

4. What are the minimum requirements for the battery?
-> 
Without regulator, one LED need about 3.5V battery.(maybe vary according to BIN code)
And need about 0.8~1.0 current.
For example, If you wanna make double...and need 3 hour burning time.
1) serial LED connection
-> you need 7.4V 3Ah Lithium ion or 7.2V 3Ah NiMH battery.
2) parallel LED connection
-> you need 3.7V.6Ah Lithium ion or 3.6V 6Ah NiMH battery.
With regulator...you can use lower or higher voltage battery.


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## rubens (May 13, 2007)

So, since the heatsink mod is easier, i think that´s the one.. (all i have is a dremel and no experience)
Also, could you explain to me what a clear manicure is?

I was planning on using AA batteries, so for a good run (~3hrs), wich type of configuration woul be good? Without the regulator it should be at least 5 AA in series, although i don´t know how long it would last..
I thought about the serial led configuration with a resistor - is there a cheap option for a regulator?

look at this: do you think it is a good deal to get it and use the components? http://www.kaidomain.com/WEBUI/ProductDetail.aspx?TranID=3162

actually.. they sell a driver for the seoul - it says it´s for 3 seould in series, but do you think it can be used with 2 leds?
http://www.cpfmarketplace.com/mp/showthread.php?t=169333

also, wich should i buy: the emitter or the star?

Sorry for all these questions.. i really dont know anything...


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## Narajjang (Dec 21, 2006)

rubens said:


> So, since the heatsink mod is easier, i think that´s the one.. (all i have is a dremel and no experience)
> Also, could you explain to me what a clear manicure is?
> 
> I was planning on using AA batteries, so for a good run (~3hrs), wich type of configuration woul be good? Without the regulator it should be at least 5 AA in series, although i don´t know how long it would last..
> ...


Hi~ rubens

1. A clear manicure means...transparent nail lacquer.

2. If you make double Seoul P4 in serial connection
and use AA sized NiMH battery...(1.2V 2700mAh)

6 serial connection -> 7.2V 2700mAh
the current to LED is 800~1000mA (depend on resistor capacity)
-> burning time is 2700 / 800~1000 = 2.7~3.3 hrs.
(but actually shorter than this. Due to heat loss..ect)
If you want longer burning time, 
make 2 set of 6 serial connection cells and make parallel connection between 2 set.
Then burning time will be double.

3. do you think it is a good deal to get it and use the components? http://www.kaidomain.com/WEBUI/ProductDetail.aspx?TranID=3162
-> I think buying this and modification will be a good work.
For example, use head part and connect with external battery pack.

4. http://www.cpfmarketplace.com/mp/showthread.php?t=169333
-> I think it can be used with 2 LEDs.
And you shoul know is...this is a buck driver.
Input voltage must 1.5~2V higher than forward voltage(Vf) of LED.
For example, 2 serial connection of I bin Seoul P4(Vf = 3.25~3.5V)
You need... 2 x (3.25~3.5) + 1.5~2 = 8~9 V battery.(7 serial connection of 1.2V NiMH battery)
Advantages of using regulator...are...
1) longer LED life
2) constant brightness through battery capacity
3) good efficiency

5. wich should i buy: the emitter or the star?
-> star is easy to work with.

I wish you make a good work.:thumbsup:


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## Zero_Enigma (Dec 14, 2006)

Where did you buy those heatsinks? How much do those heatsinks weight? How much does your light head weigh?


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## Narajjang (Dec 21, 2006)

I bought heatsinks at off-line computer & electric part store.
I didn't measure each heatsink's weight.
Light head weight is about 120g.(except mount)


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