LED Headlight
 

Mirrored at Instructables
http://www.captainslug.com/temp/ledhl_16.jpg
In order to reduce the power consumption of the lighting system of my electric vehicle, I took it upon myself to change all of the lighting to LEDs. When it came to replacing the incandescent 18 watt 310 lumen headlight bulb, none of the drop-in LED replacement bulbs looked good to me. And none of them offered output levels that were comparable to or better than the bulb I was trying to replace.
So, I shopped around and decided to make my own. The approach I took was probably more complicated than what most of you will actually need, but since I put both available options in one headlight I can explain how to implement both.

DISCLAIMER
This guide assumes you will be using an input voltage between 12 and 14 volts. If you are using a different input voltage or LEDs of different ratings than what is indicated in this write-up you should use an LED Calculator to determine what resistors you need to use.

I would recommend this LED calculator: LED Resistor Calculator

Part 1: LED Array Running Light
This option will be the most cost effective and easiest to assemble with basic tools. It's adaptable to whatever size, shape, or style of headlight you decide upon and if needed you can tailor the output level and pattern as well.

To calculate the potential output of the array you are going to make take the rating of the LEDs (6000mcd = 6 candela = 6 lumens) then multiply by the number of LEDs you intend to use.
I used 20 of the 6 lumen LEDs, so 20 x 6 means my output is approximately 120 lumens.
If you want more intensity it's best to start by using LEDs of a higher rating. Also keep in mind that even 6,000mcd LEDs will be painful to look at directly in the dark and will need to be diffused somewhat.
You can diffuse LEDs
1. by sanding their lenses with 600 grit sand paper
2. by making a soft diffusor sheet out of 1/16th or 1/8th inch clear or tinted acrylic or polycarbonate and then sanding it with 600 grit sand paper
3. by making a heavy diffusor plate out of 1/16th or 1/8th inch thickness white polyethylene sheet

Part 1 Supplies
1. Headlight fixture
2. Thin Polycarbonate or other suitable plastic sheet
3. Bulk lot of 50 to 100 white LEDs in 6000mcd or higher
You can order these cheaply from Chi-Wing LED product shop
4. Resistors (180ohm 1/4w for 13.4v max input or 220ohm 1/4w for 14v max input)
5. 22ga Wire
6. Pack of full sheet label paper

Part 1 Tools
1. 45w+ Soldering iron
2. Wire cutters
3. Power drill
4. Tin snips, band saw, or scroll saw (tool for cutting thin plastic)
5. Super glue
6. Hot Glue (optional)
7. Scissors

Part 1: Step 1
Disassemble your fixture and measure the parts.
http://www.captainslug.com/temp/ledhl_00.jpg
You will either be trying to mount your LED array off of the original reflector plate, or by replacing the glass lens with a plastic sheet that you can mount it on.

Part 1: Step 2
Use the dimensions taken to draw a CAD template of the array plate.
http://www.captainslug.com/temp/ledhl_01.jpg
Any CAD software will do. If you do not have any CAD software I would recommend getting a free trial copy of Alibre Xpress.
Draw the shape of the piece you want to make. Then add one hole the same size as the LEDs you intend to use. You can then duplicate that drilled hole in whatever pattern you want for however many LEDs you want. Just make sure to keep in mind that you will be wiring the LEDs in sets of 4, so the total number of holes will need to be a multiple of 4.
I went with a ring shape.

Part 1: Step 3
Highlight the finished sketch and then press the PrntScrn key
http://www.captainslug.com/temp/ledhl_02.jpg
Past the image into any graphics program such as GIMP or Photoshop and then select only the yellow sketch lines and blue sketch nodes. Copy that part of the image and paste into a new image, then fill those colors with black.
Save that image as a .png file.

Part 1: Step 4
Place the image onto a page in Microsoft Word or Open Office. Format it's size on the page to match the size of the part in the CAD file.
http://www.captainslug.com/temp/ledhl_03.jpg
Put one sheet of full sheet label paper face down into your printer and print out the page.
http://www.captainslug.com/temp/ledhl_04.jpg
Use scissors to cut out the template, then apply it to the protective film/paper of the plastic sheet.

Part 1: Step 5
Drill the holes where indicated by the template, then cut the part to the shape indicated using tin snips, a band saw, or a scroll saw.
http://www.captainslug.com/temp/ledhl_05.jpg
If you are making the part out of thin plastic such as 1/16th" thickness polycarbonate or ABS it will be very easy to cut with tin snips, so a power tool won't even be required. However a band saw or scroll saw will produce much cleaner edges and will allow you to cut more complex shapes.

Part 1: Step 6
Once the piece is made, test fit it in the fixture.
http://www.captainslug.com/temp/ledhl_06.jpg
I wasn't complete happy with the look of the first piece I made nor did I like the lens that the fixture came with.
I ended up making a replacement out of gray PVC and the clear base disc from a CD-R spindle.

Part 1: Step 7
Place the LEDs into the array plate you made making sure that they are appropriately oriented with their leads bent to make series sets of 4 LEDs.
http://www.captainslug.com/temp/ledhl_07.jpg
Solder the sets of 4 LEDs together. Solder a resistor onto the positive side of each set. I would recommend testing each set with a battery or variable power supply to confirm that you have them wired in the correct orientations. If on LED is wired in reverse orientation that particular set won't turn on.

Solder all of their negative leads together to make the Neg- input, then solder the leads of all of the resistors together to make the 12v+ input.
The wiring should match the following diagram.
http://www.captainslug.com/temp/ledhl_07a.jpg
Solder leads of wire onto the Neg- and 12v+ inputs. Mark the ends of the leads with tape or heatshrink.

Part 1: Step 8
Use a battery or variable power supply to test the fully wired array.
Once confirmed that it's wired correctly, use a dab of super glue or hot glue at the back of the LEDs to adhere them to the array plate.
Once the glue is dry, Assemble and test assemble the array into the fixture. Test again with the variable power supply or battery.
http://www.captainslug.com/temp/ledhl_08.jpg
If super glue is used, make sure to take the fixture back apart and let the super glued parts dry out in the open for several hours. The fumes that super glue produces in the first 2 hours of drying will in enclosed spaces stick to and whiten fingerprints as well as fog up most clear plastics.

Part 1: Step 9
With the glue dried, do the final assembly.
http://www.captainslug.com/temp/ledhl_09.jpg
If applicable, solder the connector onto the bare leads and you will have a completed LED array headlight.

Part 2: High Power LED "High Beam"
If you want even more intensity from your LED headlight you can add a High Power LED. These are available in outputs ranging from 100 to even 600 lumens! The LED I chose is a Luxeon Endor Rebel rated for 430 lumens at @ 7.5 watts.
You can order them Cree LEDs - Led Driver - Led Fixtures - Led Optics - Luxeon LEDs - LED Supply.com which also stocks the optics for them if you want a certain output beam.

Part 2 Supplies
1. High Power LED
2. Lens (optional)
3. Small Heatsink
4. Resistor (8ohm 5w for 14v max input)

Part 2 Tools
1. 100w+ Soldering iron
2. Wire cutters
3. Power drill
4. Tapping bits (UNC #4-40 and whatever preferred size you want to use for mounting the heatsink to your fixture)
5. Super glue
6. Hot Glue (optional)
7. Scissors

Part 2: Step 1
I tore a heatsink off of an antiquated video card, sanded the base, then drilled and tapped holes for mounting the heatsink and retaining the LED onto the heatsink.
http://www.captainslug.com/temp/ledhl_10.jpg
The LED and lens are held in place by the mounting screws.

Part 2: Step 2
Using a 100 watt or higher soldering iron, solder the 8ohm 5w resistor onto the positive pad of the LED, and a wire lead onto the negative pad.
http://www.captainslug.com/temp/ledhl_11.jpg
The negative pad is thermally conductive onto the back of the LED PCB so you will need to keep it off of the heatsink when soldering. Because of the thermal transfer rate that results, a soldering iron rated lower than 100 watts is not likely to be able to keep the pad up to a high enough temperature to make a decent solder joint.
Once soldered, apply heatshrink to the connections. Then apply thermal past to the back of the LED and place it on the heatsink. Retain it by affixing the set screws to the heatsink.

Part 2: Step 3
Assemble the light unit. If needed, secure the wires to the array plate using hot glue so that any tugging on the wires won't stress the solder joints.
http://www.captainslug.com/temp/ledhl_13.jpg
These pictures show the unit before I added the polyethylene diffusor inbetween the lens and the light array. A diffusor is highly recommended because the focused output of a High Power LED is literally blinding.
http://www.captainslug.com/temp/ledhl_14.jpg
Test the unit with a battery or variable power supply.
http://www.captainslug.com/temp/ledhl_12.jpg

Part 2: Step 4
Install the finished light unit into the fixture and if needed solder on the connector.
http://www.captainslug.com/temp/ledhl_15.jpg
A comparison of the custom LED headlight and the headlight it is replacing.
http://www.captainslug.com/temp/ledhl_16.jpg
Comparison of the "running light" (Left) and "high beam" (right).

Part 2: Optional
If you add a capacitor to the circuit where appropriate, you can produce a fade affect when the headlight is switched from the "running light" to the "high beam".
http://www.captainslug.com/temp/ledhl.gif

And that's it! LEDs allow you to make extremely long-lasting, highly efficient, vibration-proof, unique, and inexpensive headlights. The same process applies to making turn signals and brake lights.
However those won't require as high of an output level and most available drop-in replacements will work fine. But should you want something unique for those too, there's always the option to make your own.
http://www.captainslug.com/temp/xb-600_024.jpg

Nice write-up!

Be prepared for lots of people to comment on INSTRUCTABLES saying how the headlight isn't DOT approved!

Added that to the disclaimer section.

Hi,

I may have missed it -- but how much power does the LED light save?

Original incandescent: 310 lumens @ 18 to 21 watts
LED Running light: 120 lumens @ 2 watts
LED High Beam: 420 lumens @ 8 watts

With the huge improvement in the uniformity of the headlight output from the LEDs, even the running light makes it easier to clearly see the road surface at night. I'll have output comparison photos up later tonight.

For the whole light system on the scooter I replaced 100 watts of incandescent bulbs with 20 watts of LEDs.

http://www.captainslug.com/temp/ledhl_17.jpg
I may have to repeat the test outside. All pictures were taken with the same ISO, shutter speed, and aperture to ensure that automatic adjustments didn't distort the results.
While the incandescent is much brighter at the center of its focal pattern, the rest of the output is fairly dim and widely scattered which makes distinguishing details difficult. The uniformity of the light output from the LEDs makes it slightly easier to see details, and the light output is a much cooler white.

Awesome write up!

Do you have any kind of reflector behind the LEDs?

Nope. The 3mm LEDs emit hardly anything backwards and the high power led emits all of its light forward in a 30 deg cone. There's a negligible amount of light to reflect.
If you want to utilize all possible light from the LED array then you'll want to make the array plate out of something translucent, like white polyethylene. Doing so will make the array much more visible when viewed at an angle.
http://www.captainslug.com/temp/xb-600_022.jpg
http://www.captainslug.com/temp/xb-600_025.jpg
LED array turn signals made with white LEDs and fluorescent orange acrylic.
Yellow and orange LEDs are difficult to find in ratings higher than 3,000mcd.

This is absolutely great! :thumbup:

captainslug -

This is fantastic work. Would LED-size interior-mirrored "cones" allow the light to be "aimed" and focused more forward?!?!?!?

CarloSW2

I doubt it would help much. Collimators/reflectors would take up space that could be used for simply adding more LEDs. The element of the cathode itself is cone shaped and each LED has its own lens.

Highlight works fine. Street signs are very easy to read when hit with white light. Here's a picture taken in the only part of the neighborhood that wasn't aglow with Christmas lights.
http://captainslug.com/temp/ledhl_18.jpg
Does a fine job of replacing the 21watt incandescent bulb.
For a faster bike I would probably want a minimum of 800 lumens.

Interesting!

Yeah, but not DOT approved. :)
It'd be interesting to see what lighting patterns would be approved.

While I love this idea - I don't have a bike anymore.

I couldn't use it on my car, for obvious reasons, but I could consider using it on the CR-X EV that I plan on building, since I will need to get a title for it anyway, I may just title it as a kit car in PA, meaning that as long as the LED light array meets or exceeds both the OEM specs for the car its' based on, and the specs laid out by PA vehicle code, it will be legally in use!

I love loopholes. :)

I saw this in another place, ahead of its time. I guess it is time to dive in. The link even has free resistors, the rest is imagination.

I keep a real low idle on the downdraft sube...upon changing a bulb up front, I noticed no power dim at said low idle. Eventually back into the hog of the classic 1157 bulbs and it power dimmed again ..... There is another means to fix this, but this post has got me thinking

I bet these leds, perma-resisted do justice for this. Great post.

I'm sorry, but why exactly are these not DOT approved? Does DOT require non-LED lights? That sounds rather odd to me, that they would have a requirement as to the specific bulb type. Or perhaps it is something else?

Anyway, those look exceptionally sharp and clean. The uniform light output is something I always wished for on my motorcycle! Great lights, and great instructions!

The only reason they're not DOT approved yet is that they haven't been tested by SAE/DOT under the requirements for headlights. end of story.

Eventually, they'll get tested, and provided the people who provide the test platform can do their job, they'll be certified for use and most likely retrofitting.

Don't look at those LEDs. Period. They are literally bright enough to burn your retina.

It comes down to lighting pattern and intensity. There is nearly 100 years of research behind lighting patterns and how they interact with the human eye. The reflectors and fluting you see in the headlamp of your car or motorcycle was designed by teams of engineers and tested rigorously to make sure it meets code for the country it's being used in. They use machines that measure very accurately how much light is going where, this allows a pattern that allows you to see in nearly all situations without blinding on-coming traffic.

Daniel Stern Lighting Consultancy and Supply

The link above is about those silly HID kits people put in their cars, but it goes into what makes a light legal/illegal. The links and PDF's will help you understand more about what regulatory bodies are looking for.

LED lights
 

This is an awesome post!

I would like to add something that the "average joe" doesn't know.
If you need a great diffuser and you have (or can get you hands on) an old lcd computer monitor/ lcd tv set that is dead/ cracked screen, etc., dissasemble it carefully, and on the very bottom of the stack of the lcd array, there is a piece of custom made diffuser for the backlights, which are a couple of very small florescent bulbs taped to the sides. be careful removing these, they break easily and contain a microscopic trace of lead!! Ha Ha... so does your solder!! LOL

The CCFLs in LCD screens have mercury

Fantastic, I vote STICKY for SURE!!!

I am seriously thinking of doing this as everything you said is well within my capabilities and the writeup was nothing short of awesome!

One last note

Typical Motorcycle Headlight output: 700 lumens
High end Motorcycle Headlight output: 1200 lumens

Achieving equivalent intensity requires using arrays of high power LEDs, in groups of anywhere from 3 to 9 individual LEDs.
You also have to be mindful of the angle of output of the LED. The model of LED I intend to use for my next electric motorcycle project has a 180 degree output and will require a collimator in order to utilize all of its light output.

As such I may end up making a second chapter of this guide to cover such models that do not have factory optics options.

What is the average output of a typical car? I drive a toyota corolla...

I found some 55,000mcd LEDs on eBay for double the price you paid for your 6000mcd but their angle output is only 20 degrees plus or minus 10 degrees.

Does that mean that for 1000 lumens I only need roughly 18 of these LEDs?

Typical automotive halogens output 1500 lumens per bulb at 55 watts.

1,000mcd = 1 candela = 1 lumen. So a 55,000mcd LED is only 55 lumens.

to get 1,500 lumens you will need 30 of those 55 lumen LEDs per headlight, but you will only get the same intensity level if you have optics to go with the array, or make the array so that the LEDs are focused to converge at an ideal distance. If you can find the datasheet for those LEDs it will tell you want the drop-off distance is for their output.

You may not be able to replace your automotive high beams with LEDs, but fog lamps or running lights are very possible.

I rarely use my high beams, if ever... I can't think of a single instance since I first started driving that I've actually NEEDED to use high beams... The closest incident was when I Was driving a 4x4 in bumf*ck nowhere in costa rica and there wasn't a light in sight (pitch black) but even then the low beams were just fine.

So you're saying the average HIGH beams are 1500 lumens or the average LOW beams? I would love to know both answers. Also, what do you mean by "intensity level" and "optics" ?

Also, I calculated that If I were to do 1500 lumens then the LED's would draw approximately 4 watts of power, are my calculations correct or am I way off? How much would they draw at 1500 lumens?

something is off your not going to get headlight brightness with 4watts. LED's are good but not that good :-)

I was thinking of multiple mini arrays on dual axis swivels so I could "align" and "tune" the lights to replicate the pattern of regular head lights. I also want to use WARM white led's I really had the bluish cast of the cold white units.

This is now my go-to replacement LED headlight.
http://www.captainslug.com/temp/streetmate_007.jpg
http://www.projectresponder.com/pse/...d-light-04.jpghttp://www.projectresponder.com/pse/...d-light-05.jpg
800 lumens @ 10 watts
Vision X Solstice Solo 2x2 10watt LED Euro Beam Off Road Light

A bit spendy at $119, but it comes with its own driver that accepts anything between 9 and 50 volts, is waterproof, and comes in three output options (spot, euro, and flood).

ohhhhh those are nice but man I would need 4 of them. Ouch $480 but drool for sure. I wonder if they have them in 4000k or so I hate the blue cast of the cold white.

Been looking at doing this a while back to my car, but there was no good write ups on how to do this. Now, i can give this a try.

Love these lights
 

I've been checking out lights for my bicycle ever since I started doing ultra events. Believe me, if this light is all that is advertised, it is a bargain. I'm pretty sure you'll see one of these on my bike next season. Thanks for posting the link.:thumbup:

Glad to see all the ideas! Thanks.

I used Philips LumiLeds Luxeon LEDs in a couple of non-automotive applications, and am impressed with their robust design, specified outputs, and overall quality of construction.

They have a new Luxeon Rebel LED designed especially for the automotive industry, should be an interesting little unit...

I hope to reverse engineering the existing daytime-running LED headlights from a new Audi. I learned a lot about signal light design by reverse engineering turn signals from my local junkyard.

Thanks again for all the information and expertise!

Excellent thread! I was just looking up information on installing LED bulbs on a headlight to maximize battery use.

I also came across these LED bulbs designed for autos. Maybe if you tinker around with a couple of them and align them just right, you might get some decent lighting. Well, maybe at least for driving in areas were its not pitched black.

They are pretty cheap, I think they might be worth a shot:

2 X H3 Headlight Fog Light 9 SMD LED Xenon White Bulbs - eBay (item 130352670433 end time Jan-14-10 15:49:07 PST)

H11 36-LED Car Fog Headlight Light Foglight Bulb Lamp :eBay Motors (item 160373677145 end time Jan-27-10 01:54:48 PST)

I think you've done a very good job here.

The only thing that I would add is this. Isn't your electric bike considered a "bicycle"? If so, being DOT approved lighting isn't really an issue, right? Also, for all that work, which is awesome, don't get me wrong, you could have just added 3-4 battery powered LED bicycle lights which can really light up the road.

I used to bike commute and I had a small "array" 3 lights which totaled something like 12 LEDs and then 2 small halogen bulbs inside of those. They made by Bell and only costs $12 each.

That would be zero draw on your electric bike's system and probably light up the road more.

Just food for thought.

I revisited this thread the other day and it got me thinking.

Pretty sure low beam is 55 watts, and high beam is 65 watts. The biggest difference is the aim. So if 55 watts is 1500 lumens, I would think 65 watts should be about 1773 lumens.

I looked up the ebay link on page 1 for the small LEDs and if this would work, it would be good deal. 5mm LEDs, 16000 mcd typical, 18000 mcd max. 100 for about $12. So at 16000 mcd, you would need 94 LEDs for low beam, 111 LEDs for high beam. Arrange them on a PC board into a 2 1/2" square or rectangle or round or whatever best matches your existing headlight, and add the appropriate resistors.

Get a cheap set of junkyard headlight bodies to play with. So you can use the headlight glass as the diffuser, and can put in your old headlights if needed. Cut the back off enough to be able to mount the LED board inside the back of the headlight body. Make sure you mount the board so you can aim it as needed. Seal up the back of the headlight with caulk and rubber or whatever works.

Would this work?

Probably not.

While it's a great idea, and is the best way to build LED panels for lights that don't light the way, so to speak, the optics of headlights are designed to take light from a single point and focus it on a single point further back, it seems.

Of course, I guess this isn't necessarily true, either, because many lamp casings have a diffuser in the front so that the only light that gets out of the lens is reflected off the housing.

There is a thing about rounded top LED's that you can narrow their light output or expand it by changing the shape of the resin that the diode is encased in. If you file the top off, the light output is effectively straight out only. Not sure how that could help or hinder the experiment, but it may help with light focusing.

Are you interested in trying it? I'd like to see the results if you are!

I do have to ask, though - Is it just the lens that's DOT approved, or is it the entire light assembly? Please, if you're going to answer this question, I'd like to see some reference or data of some sort that proves one way or the other, not just a thought.

I would like to hear other's thoughts too but I would like to try it.

I know with a light bulb, light goes out in all directions. The housing is a parabola shape and collects whatever spills backwards and sends it all directly forward. The light that doesn't reflect off the housing can still go all which ways out the front of the lens. So I would think the diffuser in front of the bulb would send all that forward light backward to the housing so ALL the light ends up going directly forward. It's either that, or the diffuser in front of the bulb is there to avoid there being a really bright spot in the center of the beam, rather it spreads that light out over a wider area to reflect off the housing.

With LEDs it would already solve the problem of having to collect the light going backward, since there would be none.

If the diffuser in front of the bulb is there simply to avoid a bright beam center, and the light is OK to go out to the sides some, then LEDs alone would be fine since it would be an even light output over the entire square.

If the diffuser in front of the bulb is there to block the light that can go all directions and focus ALL the light directly forward, then filing the LEDs would so the trick. Seems like the best way would be to solder them all in place, then run the LED board over a flat sanding block.

Without filing the LEDs, light would go +/- 20 degrees according to the LED specs. That may or may not be a good thing, one would have to try it both ways.

Not sure about DOT approval. However my thought was use stock headlight bodies for a built in diffuser, an easy mount, keeping weather out, stock appearance, and easy reversal if needed. I would think that law enforcement wouldn't hassle you as long as they're aimed correctly, and according to calcs they should be a similar light output to other approved headlights. They would probably just look like the whiter lights of more expensive cars. I think what the cops are looking for is people who are using those super bright off road lights.

I do have one question. You wire four 3.3v LEDs in series so 13.2v is needed, which is close to alternator output. So why do you need a resistor?

to control current - wiuring series controls voltage while the resistor controls current. led's are current hungry give them current they heat up which makes them draw more current which makes them hotter which makes them draw more current - get it? till they melt down.

so you have to regulate the current to stop this runaway effect.

When dealing with LED headlights in general, why not aim the diodes away from the road, bouncing them off of a highly reflective rear cover that would work as a diffuser and an aiming mechanism. It seems to me it would limit the problem of being a very directional light. Enough LEDs would give very bright light while also being diffused and spread out over a larger lighting area area, like a standard filament bulb.

The design would be something like that of high beams on a tradtionally lighted car.
/ --------------------
l D )-------------------
\ -------------------

Something like that....

The "D" would be the LED while all other symbols would bascially be mirrors...

Kinda hard to fit 120 LED lights and 450ish mirrors into a common headlight housing, I'd think.

Wagonman76 -

I say go for it. I'll consider it on my next vehicle, since Cara is no longer an option for modding (totaled, being picked up at some point when I get my insurance check).

After some more thought, I'm fairly certain you're correct about the reflector pattern of the light housings. I'd want to be sure to mount the LED's on a reflective (mylar?) surface, though, because the diffuser lens will partially reflect light back toward the mounting plate. Best to salvage every photon we can, yea?

I'm interested to see your results here. I assume you'll be doing this with a spare square light? (From one of your GM vehicles.)