I have a small collection of the tall halogen pole lamps with the dish shaped reflector which lights the ceiling. I'm actually fond of them and like the indirect light they provide. I don't like burning 500 watts of power though. So I thought I would try replacing it with LEDs.
A direct replacement for the halogen bulb gives of a fraction of the light, so I found some modules which are about 2 inches square using 50 watts with about the brightness of a 300 watt bulb. There are also 100 watt versions in the same package with the brightness of a 500 watt bulb, but I figured I'd start with a lower wattage to see how well I can get rid of the heat.
I decided to use some old frying pans as heat sinks. I started with the smaller 10 inch pan which could almost fit inside the lamp dish. But that would leave no room for the electronics so I left more space between the pan and the lamp dish. Just to get an idea of how well the heat sink works, I fired it up on the bench after sanding off the Teflon under the LED and applying a bit of heat sink grease.
warm. The frying pan... I mean heat sink it pretty warm to the touch,
right next to the LED. So clearly the LED isn't doing a great job of conducting the heat to the heat sink. The LED temp is reached pretty quickly, much faster than the heat sink warms up, so the limiting factor seems to be the LED and not the heat sink itself.
I am going to finish this, but I don't see how the 100 watt LED could possibly be used. Anyone used these before? The construction is a thin steel plate slightly large than the LEDs themselves, just large enough to have mounting holes. I can't tell how the LEDs are thermally connected to the plate. I suppose there is a circuit board inside which is not conducting the heat very well. I guess this may require building my own unit if I want the full light of a 500 watt halogen with a 100 watt LED.
I will say the 50 watt gives off lots of light. I wonder if it can be dimmed?