want to build a simple light

Hey folks:

I'm thinking about building a very simple DD K2 light as a room-flood-light, driving somehting around 29 K2's in series and can plug directly into the wall. If I use UxxN K2 LEDs, 110v/4.5v(Vf)=24.4, so say use 28-29 LEDs to be safe. I am going to use an aluminium block and thermal epoxy the LEDs and wire them in series. What should i do beside connecting + terminal of one to the - of the next one and use the right terminal to match to wall outlet when I put them together? (of course I will plug it into a surge protector and use a fan to cool it)


And where can I get a large al block for the thing? I'm thinking of 11" x 8" x 4"

(of course I am also aware that I may sound like an idiot for wanting to connect that many K2s together, I'm just dreaming)

thanks,

Nick

Sure you don't need an electric space heater.. cause that's what 30 K2 leds driven at spec are going to do.

eh, that's about 100-120 watts of power, no worse than a conventional incandescent bulb.

But can the K2s take that much power in series

I suggest you convert the AC to DC with a full wave bridge rectifier (600V rated). Otherwise the K2's will only conduct on one half cycle and the other half cycle will reverse voltage them and blow-out at least one. FWIW 120V RMS is 170V peak. So each of the 29 K2's would have 5.86V peak across it assuming they all are equal... A fuse and a series current limit resistor (about 50 ohms 100W, you'll need to play with the value a bit) are also wise additions.
The block of AL you describe can sink a fair amount of heat, but it needs surface area to dissipate that heat. A smaller mass with many fins would work better.

My opinion is worth every cent it costs, but that many K2's in series rattles me.

Definately AC-DC Try a CPU-heatsink, maybe 2 next to eachother, in a regular 300w or 500w Flood-light housing you can find at your hardware store...

Cheers !

Maybe perhaps a set of Luxeon3 stars mounted to an aluminum girder that stands up like a floor lamp.
Then you can put a wrap around diffuser of some kind over the leds.
The electronics can then go in a pedestal at the bottom of this.
Is this kinda what you had in mind? :thinking: