Ridiculously Over-Powered Quadrotor Spotlight Kills Battery, Blinds People


Flying quadrotors at night is awesome — but being in the dark tends to be a problem for not crashing them… Tired of not being able to get successful GoPro videos, [Diode] decided to strap a light to his quadrotor. A 3000+ lumen, 50W LED to be precise.

He found the 50W LED for $20 online with the driver! The only problem was it gets super hot. He salvaged a heat sink from an Xbox 360 which helps to keep the temperature at bay… but also increases the weight of the quad by a bit too much. Luckily his quadrotor is pretty powerful — but with the added weight, and 50W power drain, his flight time went from 15 minutes… to about 3 minutes.

Three of the most awesome minutes ever! Just watch the following video — the night-time possibilities are endless!

Now if only the Spruce Goose of Quadrotors came to fruition… It would have had no problem carrying the extra batteries and LED!


  1. ChalkBored says:

    Just as a warning, “Three of the most awesome minutes ever!” were not included in the video, so don’t get your hopes up.

  2. Bosse Sandholm says:

    I think the reducing the weight of the cooling for the led is where you should concentrate.
    Can you find a lighter heatsink and place it and the LED closer to the airflow from a lifting propeller?

    • Greenaum says:

      Even a separate fan can provide better cooling per weight than just a chunk of metal. This should be obvious for anyone who’s seen inside a PC. But yep surely there’s some airflow somewhere he can use without crippling the flight. Maybe the heating effect would make the airflow faster, tho probably not to any net gain.

  3. Alan says:

    Replace 1x 50W light, with 4x 12W lights. Each heat sink is smaller, for a greater combined surface area, so they should also be a tad lighter.
    Four lights are easier to balance for flight, too.

  4. kami says:

    Very cool, I just wonder what a liquid cpu cooler would do instead of using the heat sync from an xBox the weight looks to be all on the side with the light. possibly distributing the weight.. But for that price, one could probably get lights that weren’t as hot producing the same lumens

  5. Rich Grise says:

    Would some kind of engine/generator combo have a better energy/weight ratio than batteries?

  6. Diving Spagetthi Monster says:

    That thing needs two small heatpipes and a 2 small wide spaced air coolers with little air resistance, similar to the old round zalman GPU coolers: http://thumbs2.ebaystatic.com/d/l225/m/mcCBWwZMydEARjWQjDcklYw.jpg. Heatpipes start at the LED and the coolers are placed near the LED in the downdraft of the front rotors.

    Maybe hack a broken laptop CPU cooler (since these are small and have heatpipes), split the cooler and place each half under each rotor

    • Greenaum says:

      Yup, active cooling of some sort, even just a fan, is definitely the way to go. With proper design perhaps the fan could provide enough boost to offset the extra weight?

  7. danieljlouw says:

    I bought 5 of those LED’s for something like $17 shipping included to South Africa. They are really stupidly bright!

    Some things I’ve learned while playing with them: They tend to automatically regulate current if you are below the forward voltage. So the heavy CC driver circuit is strictly not needed. Get something like this http://www.amazon.com/LM2577-Adjustable-Step-up-Converter-Module/dp/B008HMETBE and undervolt the LED. I think their forward voltage is something like 33v? During my tests I’ve noticed that the current shoots up as you get closer to the forward voltage with very little increase in perceived brightness. So that leaves me to assume a lot of the power goes to heat == efficiency goes down as current goes up. You should get away with a smaller heatsink then.

    Remember your quad has got four big-ass fans on it. Try to mount the LED+heatsink in such a way to take advantage of all that rushing air so that you can use an even smaller heat sink.

    Happy night flying!

    • di0de says:

      Love the ideas, more testing to be done for sure.

    • AKA the A says:

      The way we humans perceive almost anything (sound intensity, frequency, light intensity…) is not linear, but logarithmic…That and the fact that all LEDs loose efficiency when driven at max rating ;-)

      btw a CC driver is must for LEDs, the voltage/current curve is way too steep to use CV regulation, the reason it did not blow up on you is because the regulators overcurrent protection is kicking in ;-)

      • danieljlouw says:

        True about the logarithmic perception! I read somewhere that for LED flash lights you need about 50% more lumens before you notice the increase in brightness.

        About the LED, for my testing I used a bench power supply in CV mode. The current setting was on about 3A, the volts set at 32V (IIRC) but the LED was only drawing ~1.5A. I knew that if I increased the voltage any more the current will shoot up to max that the supply can supply.

        These COB (chip on board) LED drivers have 50 individual 1W blue drivers covered with the yellow phosphorus rubber you see in the pictures. The LEDs are in a 10S5P config or something like that. The internal resistance might be sufficient enough alone to limit current at high temperature (>60C)?

        I moved to a new house over the past two weeks, so all my toys are still in boxes and crates. When I have the chance I will do some more testing again and report back!

  8. Im working on a quad with lights and other bits for a project of mine, will have to check these LEDs out, will sure to post to gizmodo my project when completed :)

  9. Dodo says:

    Why did he solder the led so strangely? It seems he soldered it to the internal bus bar via a mounting hole. Normally the two metal bars sticking out are the pins you connect the supply to.

    WIth this type of package: The pin closest to the + sign is the positive lead (no shit… :P)

  10. soopergooman says:

    why not mount it so the down thrust from the blades does the cooling for you?

    • Stu says:

      That’s what I came to say, those props probably generate more cooling capability than a rack of servers on full tilt!
      All he needs to do is put the LED on the bottom of a short pole pointing downwards from the Quad body, and prop it all up on some legs. Could probably reduce the size of the heat sink too.
      And why do I get the impression that the Quad didn’t fly all that well to begin with? Seems he might have the PID settings all wrong. Either that or he’s a rookie pilot.
      Oh and next time, TAKE IT OUTSIDE IN THE DARK!

  11. Rustin Haase says:

    If I was to take up this hobby I would definitely want to 3d print my own propellers. It seems that one would go through a lot of them. :-)

    • Stu says:

      Not if you know how to fly.
      Sure you get thru a few in the learning process, but after you know how to keep it in the air and learn all the pitfalls, flying it around relatively risk free and safely, then you only rarely need to change them.
      I also can’t imagine a 3D printed piece having the smoothness that a prop requires, I was going to have a go at taking a mold of my props, then pouring PU Resin replicas.

      • Thinkerer says:

        +1 on this. Printing may or may not make more or less smooth finished pieces but I’m guessing they won’t have the necessary tensile strength nor the balance of a…er…prop-erly made one. (sorry)

  12. Rodger says:

    If we only had 4 high-power cooling fans… we could use a smaller heat sink… Wait,its a quad!

  13. x3n0x says:

    This is one of those cases where bigger != better. Do you really need 3000lm to see? A couple smaller LEDS would probably be a lot more effective if you want to be able to shoot video and get a worthwhile flight time. It would allow you to spread out the weight and heat load as well as illuminate a larger area. Though it is still pretty awesome to see a quad floating around with what amounts to a police searchlight (almost) hanging from the front!

  14. Chris C. says:

    The nighttime possibilities are endless. Or last three minutes. Whichever comes first. ;)

    I’m not sure you could put the LED/heatsink in the airflow from one of the props without causing some loss of hovering efficiency. Which would probably exceed power loss compared to running a separate fan. Propulsion requires creation of significant pressure differentials, which is harder than merely moving air, and not needed for mere cooling.

    • lastchancename says:

      I was hoping someone would point this out!
      He may get enough cooling by sampling airflow -above- the rotors, but still keeping in mind the need to balance any constriction or obstacle across all the rotors, Or possibly increasing the heatsink area – not using a block type,sink and waiting for sufficient airflow before turning the LED on.

      • Karl Wilson says:

        not a quad guy, so I have no idea, but I’m curious… would it be possible to build the frame out of a light metal and make it the heat sink? It would provide plenty of surface area that’s equally distributed across the entire craft and takes advantage of the built-in air-cooling offered by the props without getting in the way of airflow.

  15. Whatnot says:

    Attach a hot air balloon on top of such a LED and you got something going, the heat of the LED will extend flying time and you can use battery powered props to steer it around.

  16. CyberScann says:

    If you have the money for all this buy a second gopro mod it for night vision and add an ir ring it will require a lot less power and still get awesome shots and video

  17. strider_mt2k says:

    Interesting that an xbox heat sink provided usable cooling.

  18. El_AMPo says:

    This reminded me of something.. Oh yeah!: http://i1.ytimg.com/vi/xn0rrsweqog/maxresdefault.jpg.

    Anyway for the serious part of the post, try using a smaller heatsink and a EDF or a small 5×5 prop with a 800kv motor for the cooling, at low throttle it should be more efficient than the stock fan + heatsink, you don’t care about the noise do you?

  19. Josh Martin says:

    For positioning a 3 watt LED is enough (a nice directional halo results). But I also wanted a BRIGHT (numerous Cree XMLs with PWM dimmable driver) quad to be the UFO of the neighborhood.

  20. Dustin says:

    What I noticed in this video is the exposed XPS foam board on the walls. Which is a violation of building code almost everywhere due to the susceptibility of ignition from even small heat sources. That stuff should be covered.

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