# DIY Headlamp



## fire2727 (Dec 14, 2008)

This is my first thread so please be gentle 

Ive put together a mountain bike light, 12v 7ah sealed lead battery, inline torpedo switch and a 50w 10 degree dichroic reflector lamp. Im very happy with the results, biggest problem was finding a housing for the lamp that wouldn't melt :duh2:

With the above in mind I was thinking of making a headlamp....30w dichroic lamp maybe 6 or 12 volts.

Any help or pointers will be mighty appreciated, took me 6 attempts to get the bike light right:duh2:


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## vtunderground (Dec 14, 2008)

fire2727 said:


> ...biggest problem was finding a housing for the lamp that wouldn't melt.



Have you considered going LED?


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## yellow (Dec 15, 2008)

buy a cheap D-celled light and use the parts of it for the housing.
Cant be less work + good looking

at least the head part and the back end can each be made into an individual light

example:


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## fire2727 (Dec 15, 2008)

Wow Yellow that looks good, if my bike light falls apart this is how i will do attempt number 7 

As for my yet to be built Headlamp ( for fishing )

vtunderground, Yes led's are the future, and after reading some of the threads on here im very interested, is there an idiots guide i understand a few things about led's but, ........

1.What does a lux driver do & do must i have a one? 
2. How do i match one to the led's im using? 
3. The big one for me how do i calculate the led's to match the 50w lamp im using now?

Sorry in advance if these questions are hopelessly stupid


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## yellow (Dec 15, 2008)

phuuu, difficult

1st of all: the 50 W lamp uses *4.2* Amps (50/12) at 12 volts
one led about 0.85 A @ 3,7 V.
That would equal (roughly): 3 led for the 12 Volt, multiplied with *5* for 5 times a current of 0.85 mA (0.85*5=4.25)
means: when using *15 led*, You have a light that runs on the same current than the halogen ...
The difficult part is to reduce this number to come to a useful light, that is buildable, cheap and runs safely for the time You want.

I would try it this way:
*1st:* what kind of battery pack do You want to use? (System, Voltage) That is Your *starting point *
* from that You decide Your number of led, 
* the number of led asks for a specific driver,
* all together sum up to a certain current and 
* the runtime You want makes how big the pack gets (= number of cells) 

the cheapest and imho still best idea for You to start and get a light in useful budget:
order 2 lights from dealextreme or kaidomain, else such that have 4 individual led, or with one Seoul P7 or Cree MC-E,
and that have a diver mounted that runs on the voltage of the batt pack You have/want.
Then take only the heads of these lights and put a cover on the end that has wires and switches to battpack mounted.
Put them on Your bars with light holders, makes "one" light running on *8* led .

"Just" 2 might be less bright than Your 50 W, but it seems very bright because of the white led light, the two beams can be individually aligned, it is doable, still cheap and bright enough.
When doing so, and while using these light heads, You learn a lot on possible improvements and then have the housings to start real modding.

PS: much led means much heat means much heatsinking --> much weight. 
If used on head too much


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## fire2727 (Dec 16, 2008)

phuuu indeed ok I see........step by step.....

I' ve got a laptop that is beyond repair im going to look at the batteries.
I'll be back with pictures and hopefully a bit more idea of the light im wanting to build.

Huge thanks so far guys.


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## fire2727 (Dec 16, 2008)

Ok step one sorted battery pack it is a Li-ion 11.1v 4800mAh,

The battery pack will be remote and will have a inline waterproof on/off switch.

Im hoping to run the light for about 2 hours, I'll be using the headlight for fishing, so it will be turned off more than it will be on, maybe on for 5 - 10 minutes and then off again for 20 minutes. Maybe 12 hours fishing time.

Im wanting the light to be as bright as possible (aren't we all).

Thanks again for your time and patience.


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## gillestugan (Dec 17, 2008)

Well, as bright as possible is not always the best. I wouldn't want to go fishing with a too bright lamp as the glare from the water would blind me.
But.. you can have several levels and then brightest is best.

One of the hardest parts with building headlamps is keeping it small and light while at the same time keeping the LEDs cool. 
The heat from a halogen lamp is mostly reflected forward, but the heat from a led goes to the backside and needs to be heatsinked.

What is your budget?
What are you going to use as housing?
Do you want a spot or a floody beam?

If that battery is in good condition you can easily run six 3W leds at maximum for 2 hours. That would give more light than a car head light.


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## fire2727 (Dec 17, 2008)

If that battery is in good condition you can easily run six 3W leds at maximum for 2 hours. That would give more light than a car head light.

Now im excited 

The housing was going to be an old stainless steel light fitting that did house a G10 lamp, im thinking no problem with it melting and it has a hinge so i will be able to alter the direction. Now im looking at binning that if im going for six 3W leds because it will not be big enough:shakehead or can i increase the strengh and lower the number of leds.

More light than a car head light you say woo hoo


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## yellow (Dec 17, 2008)

its the outer diameter of Your focusing devices (reflector/optic) and the size of Your light "housing" that determins the number of led to fit into.
4, maybe 5, is max for the "usual" D-cell light head
this number of led can compete with 20 W systems, 
50? dunno. Will be less bright, but might seem as bright because of the white output. 


Also read the posts of "Seoul P7", "Cree MC-E" and search for "Lupine Tesla"
The leds are quad emitters - 4 led in one package - and would reduce physical size.

While I dont like the P7, an example: 
three of them should beat the 50 W Halogen with ease (if You find a reflector or optic that works with it) but need less power.
They run on ~4 V and 800 mA, so all data with Your 12V/7Ah pack would end with a runtime of 7 hours
(in reality more at 5-6 hr, but ...)
--> You can have a smaller pack
but heatsinking such a monster will not be easy


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## gajslk (Dec 17, 2008)

How about mounting it to an old metal hard-hat for heat sinking? The side benefit is that the mind-reading aliens won't be able to learn where all the best spots are and steal your fish!

Gordon


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## gillestugan (Dec 17, 2008)

haha. Maybe one of those 5lb military helmets.

regarding output:
A 12V quartz tungsten 55W halogen common in car headlamps has an efficiency of about 25lm/W so total output is around 1375 lumen.
One cree XR-E R2 can give 250Lm, so 6 of them gives 1500lm in total.

But this requires very good heatsinking. Preferably a housing made of aluminium or copper as those metals are good heat conductors.
You DO have to worry a lot about the heat. The leds will die or get damaged if you don't keep them cool. 

If you overdrive the leds they will loose in efficiency: more heat less light for the watts.
The P7 may be hard to find a suitable driver for. It's easier with a MC-E.
There are lots of threads about suitable drivers for those two in this forum.


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## fire2727 (Dec 19, 2008)

Im lost, I need to start makeing this headlight,

Yellow & gillestugan your help has been astounding, thanks for your time

with both of your help im starting to understand this magic, but i need to start buying and building before I become disheartened.

Im asking for a list of components that will give me a light that will equal or dare I say better this light 
*Tiga SL-12 Headlamp*

*Tiga SL-12 Headlamp*


*TIGA SL–12 Headlamp* - supercedes older SL-10, now with 12ah battery!​ *Normally £139.99*​ A lightweight and extremely powerful ‘Flood’ headlamp offering excellent peripheral vision for maximum safety and good visibility up to 250M.​ 

*WEIGHT:*​
 Plastic headset with foam backing and wide adjustable straps for perfect fitting and maximum user comfort. 240g 
*REFLECTOR:*​
 High quality, high reflectivity anodised aluminium​
 Dia. 103mm​
 Vertically adjustable 
*POWERFUL:*​
 Twin halogen bulbs​
 6V 6W and 20W halogen bulb. Bulb base: G4 
*LIGHT INTENSITY:*​
 6W - 120 Lumens​
 20W – 440 Lumens 
*LIGHT BEAM:*​
 Flood 
*RANGE OF BEAM:*​
 Approximately 250 metres.​
 Dia. of light disc at 1 metre:​
 Central beam: 35cm​
 Overall beam: 240cm 
*RELIABILITY:*​
 Though not waterproof, will keep working in heavy rain​
 ​




As ive got the 11.1v 4800mAh battery and charger lying around im hoping to use it.
The looks of the finished light are not an issue i'll work on that as soon as ive got a working light.

Hope this is not too much to ask:twothumbs

If the componedts can be sourced in the U.K. great if not then thats ok as well.

BIG thanks in advance :thumbsup:


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