The lighting arrangement for my bench currently consists of a double 18W 60cm fluorescent lamp under the top shelf and a single 18W 60cm fluorescent lamp below the bottom shelf. Very old skool lighting.
I have decided to start a project to drag my bench lighting kicking and screaming into the 21st century.
LED was the natural choice and after a lot of research I settled on the Cree XLamp CXA2011 which was released earlier this year. It is an 11W LED array module. It's basically got loads of small LED's on the same die.
The plan is to have 10 of these LED's lighting my bench. Five will be mounted to a long (60-80cm) heatsink and then replace the fluorescent lamps with the heatsink setup.
Of course I had to have a little play with it to see how well it performs.
I set my camera up on a tripod so that I could get the same shot of my bench with fluorescent lighting and LED lighting. I also set my camera up manually so that I could have the same exposure settings for both shots.
The aperture was fixed at f4.0, shutter speed 1/20th of a second, ISO 100 and white balance set at 4000K for both shots.
Fluorescent lighting:
LED lighting:
The LED shot is 1 stop underexposed, so basically there is half the amount of light falling on my bench from the LED lamp compared to the three fluorescent tubes. This is just a basic assumption, the rear of the bench is in darkness because of the shadow caused by the lower shelf. It is still very impressive since this is just 1 LED, so by the time I have all 10 up and running, I should have some very descent light on my bench.
I am driving this LED at 250mA, just below the 270mA that the data sheet suggests. At 250mA the lamp is kicking out 10.27W. With it's temporary heatsink it's operating at about 45 degrees C.
Here is the lamp "mounted" more or less where it will end up.
Now I just have to design a driver for the LED's. It would be easier to wire them all up in series and have one driver for the lot, but the voltage across the series string would be over 400V - not very good. I am thinking of having one driver for each LED but running from a single power supply, unless anyone else has got a better idea.