Building A 1300 Lumen Bike Light

[Brainiac27] isn’t going to let the absence of sun prevent him from biking. He has no trouble lighting his path with this 1300 Lumen bike light he built.

The light source is a 3-up star by Cree. It puts off a lot of light, but also generates quite a bit of heat which is the reason for that large heat sink. It is meant to be used with a CPU but works well for this purpose thanks to the adhesive thermal paste used to unite the two parts.

The mounting bracket is a custom job, bent from 1″ by 1/8″ aluminum bar. [Brainiac27] had some issues with length the first time he tried making it. For his second attempt he started with an overly long piece, made the bends from the center out, and only made cuts once the bends were all completed. The bracket makes it easy to mount to his bike, with the battery stored in a bike bottle and a remote switch (with attaches to the jack you can see on the project box above) hidden underneath one of the brake hoods.

The intensity of this light nearly doubles one of our other favorites.

48 thoughts on “Building A 1300 Lumen Bike Light

  1. Awesome, a floodlight that blinds everyone and puts light largely where you don’t need it.

    Check out Busch and Muller bike lights. They have focused optics so you a)don’t blind everyone else and b)get more light where you actually need it (the ground in front of you)

  2. Pity the biker or pedestrian coming from the other direction. They’ll be completely blinded by the unfocused, unshielded light. That blinding will continue long after they pass you.

    If it is 1300 lumens, some would say that light is “assault”. Some might even intentionally hit you. Or they might accidently hit you as they close their eyes. And you’d be the one at fault.

      1. Ooh, thanks for that ageist dig. I certainly try to be a considerate cyclist & driver when I’m out, all my headlights are aimed correctly. Not everyone is currently equipped with 20 year old eyes.

  3. I’d hate to be driving past this ass in the middle of the night. That light is going to blind a lot of drivers. Especially if he’s lane splitting and the lights so bright that I cant tell if it’s one of a cars headlights behind me or a bike.

    1. I’m sure that if it’s an issue someone will call the cops and they’ll confiscate it. Fortunately.

      He himself does say in closure “There are many things you can do to make it you own or even better. Most of all, it desperately needs a cutoff shield so you are not blinding car drivers. But beyond that, enjoy your LED bike light much brighter and cheaper than most bike-specific light”

  4. This is pretty bright, but it’s not going to cause drivers to go and crash. The high intensity car headlights (those blueish ones) can be around 2500 lumens each, and they aren’t killing anybody.

    1. They “kill” me even on low beams. Try driving around in a s-series saturn for a while. My head can’t be more than 1 meter off the ground. Now get a escalade with the HIDs that are mounted 1.1 meters off the ground and let me know how well you see when at a stop sign when they are behind you, or in front of you.

      I’m about ready to install front and rear strobes that I can fire when someone with them is near me.

      sorry for all the hate, but there is no reason you need to be able to see for 1km in front of you in the city during rush-hour.


    1. I am frequently blinded by run in the mill current bicycle lights, especially since so many people don’t even bother pointing them down…

      Thankfully a particular stock-light that was popular a few years back that was by default designed to point up by the idiotic designer has been phased out though so it’s getting less and less.

  5. I don’t have a problem with the mega-wattage, as long as he has a quick way to instantly-dim when a car is oncoming. A photoresistor plus a manual dim switch could accomplish that.

    As a cyclist, I would rather have both a spotlight and a wide angle light.. something to light the tarmac in front of my wheel, and something to shine ahead.

  6. Why is a heatsink needed on something thats exposed? And MOVING?

    He also cant see the simple solution to his bolt-falling-off problem, which would be to use a bar or coat hangar wire between the bolts.

    1. Because those LEDs generate enough heat to burn up in seconds with out a proper heatsink.

      Having played with high powered LEDs I can attest to the heat buildup. Sure its not generating as much heat as an incandescent, but its still enough to warrant a heatsink.

      I agree that the light output is a bit much but it all depends on how/where it is used. Though a decent set of optics never hurt. Give the guy some credit. Hackaday seems more like trolladay.

      1. Then I’m glad I bought a torch with a claimed output of 3800 lumens for £40 on eBay from a chinese seller. It does appear to put out a hell of a lot of lumens, lighting up an entire 100+ metre alleyway quite clearly. 3x Cree XM-L and uses 2x 18650 Sennybor cells. Trustfire 3T6

  7. Thanks for everyone who commented. As I said in the conclusion of the instructable (for you that did not care to read it first), “Most of all, it desperately needs a cutoff shield so you are not blinding car drivers.” I also use it hand-held most of the time so a shield was not top priority. Any PVC pipe or cap that fits over the current lens cover could easily be a workable shield.

    Most of all, there is a 19 degree lens on the LEDs, it is not unfocused. The spot is very tight, I have it set at a lower than my car headlights.

    To those who are concerned with 1300 lumens, the driver used is set up for 3 levels of illumination. I stay on about 700 lumens while biking, 1300 is reserved for high-beams. Level can be changed quickly with the remote switch.

    And to finish it off, I admit simply mounting the LED star to the bracket would have been adequate heat dissipation for biking. The heatsink just absolutely minimizes heat build up and damage to the LED, even when over driven to 1500ma.

  8. Ever consider for trails not for road? I was planning on building a couple of lights like this for cross country mountain bike training for the winter. 150$ is cheap for a bright light when name brand is over 300$ for equivalent…. I was gonna use a rc car battery for close to 6 hours of bright light :)

  9. A while back when I was modding my own MTB bike light, I remember seeing some optics that projected a horizontally oval beam pattern which would be less prone to blind people traveling in the opposite direction. This may be worth looking into if the light is meant mainly for use on public roads.

    In my experience convection cooling while riding allows driving the LEDs pretty hard, with a moderate heatsink, even in hot climes. But you need to dim the lamp during extended stops to prevent it from overheating: this is trivial with commonly available multi-mode drivers.

    Otherwise this simple build is a good example of the amazing progress high power LEDs have made in recent years, and what they enable hobbyists to achieve – kudos to the engineers at Cree etc.

    If you don’t bike, you may find it difficult to understand the quest for brightness. If you do, you already know that you can never really get enough.

  10. Honestly, who cares? I have a 3000 lumen otf light i put together, using a bunch of leds, using a computer heatsink for the leds and a custom cast case to cover the rest of it. Its 5 cree xpe r2, 1 ssc p7, and 2 xml leds.

    1. Nope, you are wrong. What you see as ‘overkill’ complaints, everyone else sees as constructive feedback that the author REALLY needs a light shield and aiming system… which the author readily admits. It’s not so much overkill but an obvious fact that a lot of blinding, directional light is not going where it is SUPPOSED to.

      In most of the USA (and Canada), it’s perfectly legal to kill a cyclist and then say you did not see them. Motorists will swerve and scream at you to get off the road unless you can MEET the road’s posted speed limit (and they believe that is the actual law, or it “should” be the law if they can ‘enforce’ it). It’s foolish to do -anything- that may antagonize or impair the vision of caged road users. All that said, the author notes (here) at least he has multiple power levels for the light, so it’s not 1300 lumens at a driver.

  11. Funny the overkill comments, since I’ve been running 3x cree Q5 on my bike for about three years now — powered by home-brew packs made from 18650’s pulled from dead laptop packs. I’m pushing probably a hair more light than his, and I’ve got it in a nice reflector from DealExtreme… I used copper VGA RAMsinks on the back of each LED for heat management and wrapped the whole thing in the head of a dollar fifty radio shack flashlight with the handle cut off. Battery Box is just a buck and a half walmart fishing tackle box, and I’ve got a rear mounted lamp under the seat that’s ANOTHER Q5 inside a cheap walmart trailer lamp housing. The wiring was even recycled from old PC power cords (of which I have several dozen for lord knows what reason)

    Home-brew Cree lamps for bikes are pretty common — and if like me you go riding at 3 in the morning, damned straight we’re lighting ourselves up like christmas trees. 1000+ lumens front, 300+ aft, and pedals that light up as you pedal…

    My qualms with his build is the lack of a proper reflector/diffuser/lens. The in-built lenses on the star are cute — but I’m not even certain they’re road legal since there’s not enough distinction between directional light and castoff. Here in NH anything over 300 lumens is subject to the same rules as cars… so the top of the fullbright should be pointed at the horizon — so oncoming vehicles and pedestrians aren’t in the line of fire.

    1. Any idea what the top end lumen rating for car headlights is? I have been looking into rolling LED headlights with normal, high and Lucifer settings. The latter of which I would only be using on NH16 N, way out in the boonies to see deer and moose, and where there is rarely any oncoming traffic

    1. You’d have to judge if this light is brighter, and if you have the capability to cool this LED when it is placed inside the projector.

      This is cheap to build, and as the author notes it is adjustable output. Assuming refit is not an issue, you could try it.

    2. A problem you may run into is replacing a single LED for several. I don’t know too much about optics but I think projectors rely on a single point of light to work. The same driver could run a single Cree XP-G LED at about 450 lumens, if that is brighter than stock.

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