From 300W to 10W — A LED Lighting Solution

LED halogen light

Halogen lights are great — they produce lots of bright warm light, but they suck a lot of juice to run. [Sven] had found a nice floor lamp years ago that was in pretty rough shape — his wife redecorated it, and he fixed it up, but between the 300W power consumption and the lack of a dimmer circuit (this thing was bright!), he knew he had to upgrade.

Like we recommend for all projects, [Sven] started by setting some goals for the conversion. He wanted to keep the warm light color tone, produce over 700lm, allow for dimming via remote, and work with presence detection.

He sourced a 10W power LED which requires 12V @950mA to run, which almost stumped him as it turns out there aren’t many LED drivers of that specification even available! Luckily, he managed to find one from China that wasn’t too large and would fit in the lamp cover with the other components. He found a large heat sink for the LED, and for safety, has even wired it up with a temperature sensor to his Arduino in order to shut it down if it gets too hot. The Arduino also provides the dimming circuit and remote control capabilities.

[Sven] admits that the end result isn’t that pretty, but lucky for him, it stands about 6′ tall so no one can see the jumble of wires and components inside! This is also only the first iteration, as he plans on upgrading it further — as it turns out, 700lm isn’t quite enough.

Comments

  1. strevo says:

    to be fair, the 300w bulb PRODUCES MORE LUMENS BY A LONG SHOT – OVER 5000 LUMENS! so a better comparison would be 60 watts worth of those LEDs.

  2. Adam says:

    Very cool conversion. Really like the remote control and anything with a massive heatsink is awesome. But I’m not too surprised that 700lm isn’t enough light. That is less than a 60W equivalent bulb. Thats a big jump for 300W to 60W eqivilant. Also he would be better off to break it up into multiple leds vs one big one. Its much easier to deal with heat and source drivers for batches of smaller LEDs. Also Philips Lumileds has small leds capable of 900 lm powered by 6V@1400mA That sounds like a lot of current but a few of those running at 1A would provide a LOT of light

  3. Max Siegieda says:

    Well at least with those modules and that massive heatsink the upgrade path is fairly clear, there are 25, 50, 100, 300W LED modules that might serve his purposes. The driver thing is pretty tricky though, I had wondered about filling a ceiling with LEDs to get light as close to daylight brightness as possible but the power draw and drivers required are just immense.

  4. fartface says:

    This screams for replacing the ugly rounded top with an aluminum block so you can put 4 of those 10W LED elements in it and the electronics down at the base. That would make a very nice light spread and give close to 70% more light. Sadly LED is nowhere near halogen in power-> lumens output.

  5. Large heatsink is most excellent.
    I would not recommend using electrical tape in that sort of setting. Either use cable ties or heat shrink tubing depending on what you’re doing.

  6. lostengineer says:

    Hard to find power supply?!?!

    Just get any universal $4 buck-boost module from ebay, power it with any old wall wart or power supply capable of 12 watts, and set it 12v @ 950mA. Tap into the voltage pot and you have dimming without a microcontroller too!

    you can use these modules to power pretty much any high power led. Add transistors for PWM dimming. I’ve got a 100w RGB LED module, each color with a seperate small buck-boost because red needs less voltage & current than green and blue.

    http://www.ebay.com/itm/5-30V-to-0-8-28V-DC-Boost-Buck-Converter-5A-Constant-Current-Volt-Regulator-/301057850532?pt=LH_DefaultDomain_0&hash=item4618723ca4

    Good start though

  7. macegr says:

    Replacing LEDs in a torchiere lamp is probably not the most efficient approach. While incandescents are often omnidirectional, LEDs are often more focused (it’s easier to focus them because you can use cheap plastic optics since they don’t get as hot). LEDs can be brighter than their lumen equivalency would suggest if installed to take advantage of this. For example…downlights with a 90 to 120 degree dispersion angle. Or spotlights with a tighter angle. LED strips installed close to the desired work area. They make it easier to put light only where you need it, but most current fixtures are designed to light an entire room.

  8. Leithoa says:

    I understand it’s a work in progress but people should get out of the habit of leaving a dev board in their ‘finished’ product.

  9. HackJack says:

    There are much better options out there:

    http://www.instructables.com/id/Convert-a-300-Watt-Torchiere-Lamp-into-a-20-Watt-C/

    Converts a 300W floor lamp to use regular light bulbs. And then, you can put in your CFL or LED bulb if you want. You can easily top 3000 Lumens with less than 50W.

  10. pcf11 says:

    LEDs? meh, stick with the classics

    http://weddingfireworks.org/wp-content/gallery/flambeaux-torches/medieval-beacons-1.jpg

    It is a torch lamp right?

  11. qwerty says:

    Making a switching driver for a certain amount of (milli) amperes is not that hard. Most switching chips out there have a negative feedback pin used to regulate voltage. To turn it into a constant current regulator just feed it with a voltage that is a function of the current flowing into the load rather of the output voltage. Hint: connect the load to ground through a low value resistor and use the voltage at the link between the load “ground” and the resistor to drive the feedback pin.
    With schematics at hand about any switching voltage regulator can be turned into a current regulator.

  12. HazardX says:

    In my spare time I’ve been doodling out various plans for a constant-current CXA2011 driver (they are Cree LED modules with outputs ranging from 800-1200lm depending on color temp and stuff). I don’t have any particular plan for such a device’s usage, but its an interesting thing to think about. The current favored method is to boost a pre-regulated supply and use the inductor’s average current to directly drive the LED module…but I’ve never done something like this before so I don’t really know how to model it…most specifically this “high” voltage (38-48V), with decent current (~270mA+). But that’s why its fun :3

    • tekkieneet says:

      Ah the old current mode PWM controllers. Linear Tech has (free) LTSpice with some of the models of their chips as well as the usual passive parts so that would help in the modeling.

  13. schlackbob says:

    sorry for being fussy but shouldnt “an led” be the correct term and not “a led”? because led is spelled with a silent “a”.

  14. Bogdan says:

    I find it very funny the ratings of LEDs… see how that 10W LED needs 12*0.95=11.4W ?

    • Dave says:

      Is the 10w the rating of the actual LED – without the LED driver? …and 11.4w the measured IV with the LED circuit driver in place? The driving circuitry will certainly suck a bit of juice…

  15. Elmars says:

    I ran into the same power controller issue with similar LEDs. In my case, I found a current limited notebook power supply. Since the PS was 19v, I hooked up two LEDs in series and mounted them on a old PentiumII heatsink. Not dimmable, but darn bright.

    http://eositis.wordpress.com/2014/06/02/powerful-led-workbench-light-on-the-cheap/

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