Introduction: 700-Lumen LED Bike Light

Picture of 700-Lumen LED Bike Light

Equivalent light output of a 70-watt halogen bulb but only uses12-watts of power.
Beam shots show a building at night 100-ft away illuminated by this LED bike light.

Detailed Specs and Parts List are given at the end of Step 8.

Step 1: Building the Enclosure

Picture of Building the Enclosure

Step 1: Enclosure
A. These are the parts needed for the enclosure and shown before cutting to size: Lexan MR10 plastic, 1/16-inch x 3/4-inch aluminum L-bracket, Hammond enclosure, heat sink.

B. Cut parts to size: 3/4-inch section from enclosure, aluminum back bezel, Lexan front bezel, heat sink slices.

Step 2: Attach the LEDs

Picture of Attach the LEDs

Step 2: Attach LEDs and Heat Sinks

A. Trim LED stars to fit inside enclosure.

B. Position stars on back bezel with an extra piece of L-bracket which is same thickness as Hammond enclosure.

C. Rotate center star 180-degrees so the + and - tabs are next to each other on adjoining stars.

D. Glue stars with Arctic Silver thermal adhesive, then clamp until cured (five minutes).

E. Good thermal management is essential for LEDs. Glue heat sink slices to top and back of L-bracket using Arctic Silver thermal adhesive.

Step 3: Wiring the LEDs

Picture of Wiring the LEDs

Step 3: Wire the LEDs and glue on the lens holders

A. Wire stars together (two small red wires) between + and - tabs.

B. Drill another hole in back bezel for incoming power. Add shrink tubing for strain relief on each side of bezel.

C. Drill holes in base of lens holders to route black negative power wire.

D. Glue lens bases to stars, preferably with Loctite 460 superglue.

E. Solder incoming power wires to stars (white + and black -).

Step 4: Final Enclosure Steps

Picture of Final Enclosure Steps

Step 4: Finish the Enclosure

A. Glue lenses onto lens holders with Loctite 460 superglue (regular superglue will frost the lenses with a white film caused by vapors as it dries). I used a flood lens in the center and spot lenses on each end.

B. Glue on a washer-nut to bottom of enclosure with JB-Weld epoxy to hold handlebar bracket.

C. Screw on aluminum back bezel and Lexan front bezel after lenses dry.

D. Attach a bracket such as the one pictured from old Vista Light, or any bracket that can fit the 3/4-inch enclosure base. I also used washers so the light can be adjusted right and left.

Step 5: Building the Power Supply

Picture of Building the Power Supply

Step 5: Battery pack is made from four 18650 Li-ion cells.

Overview: LED driver and on/off switch will be placed inside water bottle with battery pack. Battery terminal leads use a Molex connector for charging and connecting to driver.

A. Parts Needed: 18650 battery pack from Battery Space with built-in poly-switch and PCB for protection, Molex wire connectors, on/off toggle switch, buck-puck LED driver with pot for dimming.

B. Assemble the wiring harness with solder and shrink tubing. Shown in the third photo is the wiring harness; clockwise from top: dimming pot, LED driver, blue and white wires to LEDs, on/off toggle switch, Molex connector to battery.

C. I used a two-pin connector between the power supply and LEDs, but any good connector will work and preferrably one that can keep out moisture and dirt.

Step 6: Final Assembly

Picture of Final Assembly

Step 6: Add the finishing touches to the power supply

A. First photo shows the wiring harness bundled and zip-tied underneath the bottle cap. JB-Weld was added to dimming pot wires for strain relief.

B. Drill holes in bottle cap for on/off toggle switch and dimming pot as seen in second photo.

C. I padded the battery pack with pipe insulation for protection inside the bottle.
Shown in the third photo is the 2-pin connector that came with the charger. This was soldered onto the coiled wire coming through the bottle spout to connect to LEDs.

Step 7: The Completed System

Picture of The Completed System

A. Shown is the completed LED System: Li-ion charger from Battery Space - 3-hour charge time. Charger wire which had 2-pin connector was replaced with Molex connector to charge battery.

B. LEDs give a very bright white light. Bright portion of beam projects to a distance of about 100-ft and total throw is about 150-ft. These LEDs give 700-lumens of light or equivalent to a 70-watt halogen, but only use 12-watts of power including 1-volt for driver.

Step 8: Specs and Parts List

Three Cree XR-E R2 LEDs, 700-lumens, 3-hr run time on high using 14.8V 2.4Ah battery, dimmable with adjustable pot., light with mounting bracket weighs 0.22-lb (99-grams), 4 batteries weigh 0.40-lb (184 grams), 1.5-A Li-ion charger, LED parts cost $75, battery and charger $100.

PARTS (US Dollars)
Part - Price - Supplier

3 Cree XR-E R2 Lamps - $6 each - Deal Xtreme
3 Polymer Optic Lenses - $3 each - LED Lighting Supply part #170, 171
Hammond Enclosure - $8 - Newark Electronics part #1455B1202BK
Half brick heat sink - $4 - Newark mfr. part #241202B92200
Lexan MR10 12x12 inch sheet - $12 - Piedmont Plastics
36-inch Aluminum L-bracket - $4 - Home Depot
Buck Puck 1A driver w/pot. - $20 - LED Supply
Arctic Silver - $12 - LED Supply
On/off switch - $0 - Had one; only a few dollars at Battery Space

18650 Li-ion 14.8V 2.4Ah - $74 - Battery Space
Li-ion Charger - $27 - Battery Space
Molex connectors - $0 - Had some, only a dollar or two

Totals: $75 for light and $100 for power.

Final Note:
A month or two after I built this light which cost $175 in parts and was enjoyable to build, a company in China called 'Magic Shine' came out with a 900-lumen LED bike light for $80 including charger, battery pack, and a very nice enclosure. It has a three hour burn time on high and is slightly brighter than this light. It can be purchased from Deal Extreme in China or GeoManGear in the U.S.

"...a lamp to my feet and a light unto my path."


C.S forK (author)2016-11-16

very very thanx for instructables to help me in making some curiositiful projects

Babloo412 (author)2014-11-03

my bike has 12 Volt AC power system, and no battery . sir please tell me , how to use this led headlights in my bike.

ajaen1 (author)Babloo4122015-01-04

attach a diode before the LEDs to make it a square wave DC

hanlin_y (author)2012-07-23

Nice work! I really want to make this.

For cell balancing, you can use 18650 battery holders. Perhaps glue two 2-cell holders back to back and wire them in series.

mwarren_us (author)2012-01-15

Luis Leonardo's $88 Nova Star project on Kickstarter ( or ) looks very much like this too.

rprough (author)2011-09-15

The arctic silver thermal adhesive can be found on any computer supply website. for example. Just remember to get the adhesive and not the "paste" which is just for heat transfer properties that might be disassembled later.

spaghettikid (author)2011-07-24

Hi, I have finished this bike light, but whilst assembling the battery/bottle part the wires snapped off the potentiometer, and there is no way of re-soldering them on, is there any specific type of pot i should get??

nerbaneth (author)2011-06-23

Great design!

AAah! Don't insulate batteries! you want the batteries to loose heat quickly if necessary. This will shorten battery life.

snowluck2345 (author)2011-05-07

This isn't as powerful as a 70 watt halogen. Halogens are 20-40 lumens per watt.

spaghettikid (author)2011-04-17

Where did you order your lenses and lens holders from, i cannot find anywhere that will only sell 3, they only accept big +50 orders.... ?

Found it =] RS components did them in the end, but they didnt show up on google when i searched it =]

spaghettikid (author)2011-04-17

Does it matter which way up the LED's go as long as the middle one is the opposite as the others?

spaghettikid (author)2011-03-17

For the arctic silver adhesive which glue is it exactly because they have arctic silver of several types, arctic alumina of several types, the arctic alumina is much cheaper but will it still work?

700lumenLED (author)spaghettikid2011-03-24

I used the premium arctic silver from LED Supply. Any good thermal adhesive should work or contact them for recommendations.

spaghettikid (author)2011-02-23

Hello, great instructable, i am in the process of locating the parts and the hammond enclosure is the only part i am missing, could someone give the link to it as previous links given in comments have not been the right ones or are no longer available =] thanks

700lumenLED (author)spaghettikid2011-02-24

Step 8 shows all the part numbers which should still be valid. Hammond enclosure is Newark Electronics part no. 1455B1202 in silver or black. Also see 'Final Note' at very end: you can buy a Magic Shine LED light for under $90, although GeoManGear is still working on a replacement battery. They had 3 failed batteries out of 20,000 which might even be acceptable by Six Sigma standards.

knektek (author)2010-08-03

I went to lidl yestorday and I had found 2 'D' sized rechargeable cells for £2.50! The best thing about them is that they hold 4700 mAH each!

GENERALCHAOS (author)2010-07-13

... Nice and BEEFY power output im crazy about led lamps i always look for good idea like this good show

johny875 (author)2010-06-17

My fav place for part is They ship world wide, free of charge Read the customer reviews to avoid getting lemons thou ;)

Vspec (author)2009-09-03

Could this be used without the power supply? like maybe wiring it into a motorcycle stator?

Simpson_jr (author)Vspec2010-03-16

Yes, it's possible, I was wondering whether you would need a 12 volt stator,  but according to the buck-puck specs they can handle an input of 5-32 volts _DC_.
Driving very slowly with a 6-volt stator (and no battery) might... give problems though. You might have to choose between a ticket for speeding or one for driving without light ;)

One can also ditch the buck-puck and just use a resistor. you'll need a resistor capable of dissipating a lot of power and you'll need to calculate the exact value in ohms. Just google LED-calculator to find one and enter the specs found in the datasheet of the LEDs used.  Most online calculators will  show you the schematic needed.

Most online LED calculators will start protesting that the amount of Milliamperes is very high (for a LED) or that the resistor must be capable to handle a very high wattage. That's because most of those calculators aren't written for high power leds (yet) although the outcome is correct.

I'd advice you to buy a resistor capable of handling 3-4 times the load. In most  electronics (not the extremely cheap stuff)  components used can handle at least twice the load of the design which  is indeed enough, but.... The resistor may still get very hot.

There are a few disadvantage to a set up without buck-puck, When your stator doesn't give a the same amount of volts at different RPMs, your lights will dim/brighten every time you shift gears. Although rated as an 12 volt stator it might... also generate more at  high RPMs which could ruin the LEDs.
A motorcycle with battery will give a more constant voltage and have less problems.  Anyway, measure what your stator (with or without battery) is capable of before building a resistor-set up.

The beauty of a buck-puck is that it delivers the exact amount of power to the LEDS whether the motor runs stationary or at 11000 RPM without having to know too much about electronics.

It is possible to drive leds in other ways as well, even quit cheap,  but those require a lot more knowledge about the components used.

HellaCaj (author)2010-02-17

How nice of our friends in China to scour sites like this for their latest and greatest "inventions." Great work Lumen.

bronxbomber (author)2010-02-13

The magicshine is sold out everywhere, it may be bright to specs but it is really the same as this one.  As the battery it uses is junk and goes out to battery heaven in less then a weeks time.  Now maybe if you buy just the head light and add this battery it should work great.  But this one looks more fun to build and can change led to high ones.  They do have 540 lum leds which should out perform that magic-hine and get a better batter for 80+ at the website above or build your own.  cheaper to build a battery then let them, you can save $10-30 on doing it yourself.

bronxbomber (author)2010-02-13

Those wanting to know more info on the case this person used here they are
Length  Width  Height
4.72      2.82      .75 INCHES
120       71.2       19  MM
with a cost of            1-5      6-49   Quantity
1455C1202BK 9C  $11.02  $9.33 each
Photo Gallary of sizes

Was a pain to find but did now to find where to get it in stock or cheaper.  But since we now have the dimensions we can find something close to it.  Since it will be cut into parts when spend the 11.02 plus shipping.

List of where to buy in different countries
cheper at for $9.99

This really wasn't hard to place when you did the instructions but I would have never learned to search the web this good.

bronxbomber (author)bronxbomber2010-02-13

Those leds are being discontinued so a replacement can be found else where or oem site.

chris2002rocklin (author)2010-01-17

I think you look for any old aluminum enclosure. Not to defend the poor (lack of) specific build list...try to see, they have some but not sure about sizes.  

John Culbertson (author)2009-12-06

nice Job. You gotta love Hammond enclosures.

giesken (author)2009-11-22

 Great job, thx

_Scratch_ (author)2009-11-16

The (Department of energy?) is holding a contest for a company/person to make a light bulb to replace the 60watt bulb. it has to have at least 90 lumens PER watt.... quite a bit, if you create 2500 working copys of your product, and it wins, you will win 10 million US dollars. pretty cool....

BRAVODOG (author)2009-09-27

Ok where do you get the Hammond enclosure ? is it a h/d one?

chadeau (author)2009-09-15 has an adaptable bracket---go to Accessories-Lights-subheading Light mounts and Brackets---cygolite Handlebar bracket @ $14.95

qwertyboy (author)2009-09-04

the second picture looks like a car ignition coil...

chadeau (author)qwertyboy2009-09-15

Just think-if you were to use a chromed 'coil cover to mount the plastic bottle...

nightmaresyndrome (author)2009-09-05

I'm a little confused about which buck puck to get...there isn't specifically a "1a"

Could you be more specific about which one you got from the above page?? Does anyone else know? Theres no clear picture.

The buckpuck driver I used is Part # 3023-D-E-1000P ('forgot to list).

Stephen87 (author)2009-09-04

this is pretty awesome and it also gives me an idea of how to possibly make some fog lights for my truck although I am not sure how long they can be on constantly

Simpson_jr (author)Stephen872009-09-05

LEDs have a life expectancy of 20.000 to 50.000 hours and you can keep them on constantly as long as that. LEDs like these do get quite hot though so a good heath sink is a must, just like the right buck-puck driver which ensures the LEDs won't get more energy as they can handle. Larger&smaller; LEDs (in terms of power) are available, just as LED-drivers (Buck-puck isn't the only one), some of those can be dimmed. I've seen manufacturers started selling LED-Applications to light sport-stadiums recently, so the sky is the limit.

Stephen87 (author)Simpson_jr2009-09-05

Awesome, Thanks for the info

JZ Price (author)Stephen872009-09-06

The small LEDs last for 10 years. but the newer super bright ones are "over clocked" and don't last as long. But it isn't like they will just go out. A cool white LED will fade to a warm white (while the efficiency goes down). and go out. Different Brands over clock more than ever. OSRAM doesn't overclock at all. but Luxen overclocks a fair amount.

camb00 (author)2009-09-05

Cant the back of the led short out on the metal ?

joejoerowley (author)camb002009-09-06

Not really. It is a ground/heatsink.

static (author)2009-09-05

Stating the obvious. What is called the dim headlights on cars is actually low beam. Perhaps the ultimate would be to salvage the lens from a burned out motorcycle sealed beam, and use it as the starting point for LED bicycle head lamp. Some of the early automobiles actually physically "dipped" the headlamp automobiles, that too may be an option with LED bicycle headlamps.

j-plan (author)2009-09-01

firstly, awesome 'ible. this is exactly the kind of thing ive been looking to make, secondly, could you please advise me on where to get these parts? preferably in the uk :) thanks

Blue_Dream (author)j-plan2009-09-01

My fav place for part is
They ship world wide, free of charge
Read the customer reviews to avoid getting lemons thou ;)

Mike Nelson (author)Blue_Dream2009-09-04

Yeah that place is great, I've built a few headlamps for caving. Everyone else i've been caving with keeps raving saying that it's the brightest light they've seen underground.. I need better packaging though. Your enclosure is awesome!! I want to to find one with that same shape, but only wide enough for 2 emitters, I really don't need 700 lumens underground.. it's almost a detriment to other people to have the 450 i've got now.. I blind people far too often.. :D Nice work!

j-plan (author)j-plan2009-09-01

sorry just noticed your parts list, thanks dude

Simpson_jr (author)2009-09-02

I like projects like this but would like to ask every builder to... align it very well. Driving towards someone with a light like this can be very annoying and even _dangerous_ when you're looking directly in the beam of light...

Berserk87 (author)Simpson_jr2009-09-03

second. im using a couple of these around the house and they are BLINDINGLY bright. if you look at them at all, you see purple for 5 minutes.

frollard (author)Simpson_jr2009-09-03

I was going to suggest this -- from the picture of the building, it looks like the 'round' beam is aimed with its center axis level with the ground - thus IN drivers eyes. I would hate to be on a bicycle driving toward a 2000 pound car that can't see because it's blinded.

you could make this EVEN brighter with bigger leds

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