LED under-cabinet lights

November 17, 2007

The price looked good, I thought I would give them a try. They’re a clear win; for this kind of lighting, LEDs are the choice.

I bought these from LED Supply. They are one-foot by half-inch strips, each emitting 200 lumens of LED light, running on 12-24 volts DC. The price is pretty good; if you price out 200 lumens, add regulators, etc, from discrete parts, it’s easy to exceed their price ($25 per foot). My goal is to get something that is energy-saving, non-hot (not a fire hazard) that I won’t need to mess with for a long time. We have some crappy halogen under-cabinet lights already; they’re a pain to change, hot, and the heat melted the fixtures. LEDs ought to beat all that, at fraction of the power (or, if we want to be light gluttons, we can get a ton of lot for half the power).

The light is pretty good; better than fluorescents, definitely, and there’s choices (I actually think that bright white is a little too blue). I put six (a mixture of cool white and bright white) in a string, and wired it experimentally to a cheap power supply (available from the same site, looks like they got a truckload from Kodak on surplus) and checked it with a power meter, and the whole rig (including the power supply) pulled 22 watts, with a power factor of around .6 (this, of course, is an artifact of the power supply). The lights come with a dimming input, but I’m not using it.

You could easily run this on a car battery, or off the grid, if you had DC.

And yes, the price looks a little high, but they’re only going to get cheaper and brighter in the future, and they’re good for 10 years of use, 24/7, with no penalty for turning them on and off.

This shows one-and-a-half strips, with the power supplied at the left. You’ll notice that they are tacked in place with white electrical tape; they weigh next to nothing, and are somewhat flexible.


This shows a joint between two strips (with the electrical tape removed). The yellowish dots inside the squares are the LEDs. Notice the exposed wiring — this is not for a splashy location, unless you waterproof with a little silicone, or a slim casing (I can imagine routing a channel in a thin piece of wood with holes drilled in it for the lights).


I did not take the trouble of using a constant exposure for these three photos, I just let the camera do its autoexposure thing. This gives you an idea of how bright they are.


Notice how much the camera had to boost the exposure to compensate for the missing light.


18 watts of LED light (net 22 at the wall socket). You can see where one of the strips is drooping.


It would be a little pricey and delicate, but you could make a heck of a string of Christmas tree lights out of some of these.

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