Undercounter LED lighting first try

[SafetyBob]

Well I finally finished putting together some undercounter lighting. I can't remember who did it before but I should have paid more attention to what they posted. I will tell you why as I go down the pictures.

Let me first describe what and where I am doing this. In our kitchen we have a built in desk area the is normally quite dark and with a 60w equivalent CFL, it still didn't get much light. So I told the wife I would "fix" this problem. She has gotten nervous with all the small packages coming to the house over the past couple of weeks that I had to do something. Oh, and the 3C M@g with UCL, stippled reflector, and Malkoff drop-in didn't seem to impress her the same way it did me. So solve the dark desk problem here we go.....

First. I used aluminum as a heatsink. I planned on and used Cree Q5's just to see how good they would work in an undercounter lighting situation. I will spare you alot of the machining pictures other than a couple. The heatsink was 1 inch aluminum round stock milled in half. So I ended up with a 1 x 1 1/4 inch half round blank to glue my emitter to.

Below is the alum. U channel that was cut to a half an inch.

http://i225.photobucket.com/albums/dd94/reverding58/100_0507.jpg

Here is the final operation on the mill getting that precision distance to fit in the U channel.

http://i225.photobucket.com/albums/dd94/reverding58/P1010009.jpg

Next up, all components finished and ready for assembly.

http://i225.photobucket.com/albums/dd94/reverding58/100_0509.jpg

Here it is assembled.

http://i225.photobucket.com/albums/dd94/reverding58/100_0509.jpg

By the way. At I think around 50% power (yes I will get the meter out later), these heatsinks are warm to the touch. This suprised me. I didn't think they would get this warm. They are wired 4 in series.

Taken apart it was time for some gluing. Artic Alumina 2 part epoxy for this.

http://i225.photobucket.com/albums/dd94/reverding58/100_0509.jpg

Here is everything wired up with Cree optics glued on. Here is the problem with Cree optics. Unless you have a circuit type board that you can have power applied to from below, you have to fight soldered wires. So each lense had to be filed or in my case Dremeled in order to go over each wire and get close to sitting flat. I took the adhesive strip off the optics and just epoxyed it on. Thought about hot glue, but I would have had to of gotten out of the chair and there was the epoxy right infront of me.

http://i225.photobucket.com/albums/dd94/reverding58/100_0514.jpg

Sorry this isn't the best picture of the results but it shows some stuff that you really need to know before you go down this road. Here is the picture, then we can discuss this below.

http://i225.photobucket.com/albums/dd94/reverding58/100_0514.jpg

Unfortunately the left most light is glaring right at you off the phone. That is what the wife wanted and received. Infront of it and to the right, a lighted area to use to write messages. I guess I should mention that routinely our kitchen is dark in this area. Great lighting everywhere else, just not here. The big dark spot in the middle is the laptop. Don't want that illuminated. The mouse is nicely illuminated along with the right side of the top. All of these lights will remain on all night for general night lighting also. I have some Northstar led's in the hallway to make a nice pathway at night if you have to go to the bathroom or kitchen. They also come on automatically if power goes out (yes I was bored). Here is a link to them.

http://www.theledlight.com/northstar.html

No they are not state of the art, but work really, really well for night lighting. I use a 12VDC regulated power supply to power them. Idiot proof.

But on to our discussion. What I wanted most to explain and warn you about is what I would do different. I powered these Crees (four of them) with a Mircrodrive9 at 350mA. You can also drive it at 700 or 750mA also but it was to bright. After the Microdrive I used a Zane ADM-34L-12V PWM dimmer. You would be better off to use a 12VDC wall wort and this dimmer (and I may do this project over and will use that) because the dimmer only function to about 30% then it just goes out. This same dimmer with power from a regulated 12 volt supply (for the Northstar hallway lighting) functions perfectly. So there is change one if you are keeping score.

Next.Optics. The two lights on the left were 8 degree spots as I recall and they give about a 6 inch circle that is a spot and it is a very good spot. The lights on the right are the diffuser, kind of egg crate looking thing. Look at the Cree optics and you can get the real name. I should have used the diffused lenses for everything. Unless your light is going to be 3 feet from the object you wish to light in the kitchen, use diffused. I am going to take a real 18 inch Chinesse Lowes flourescent fixure and strip it clean and put some Seoul P4 stars I have here in it with another Microdrive I have here and see how just the star lights up the plastic lense of the cheap light. I think the new generation of LEDs are way to bright to use without putting them in some sort of fixture to tame them down unless you have over 3 or 4 feet to kill before lighting something.

How about that color. These are way to cold. I was thinking about cleaning up one of our Candlepowerforums vendors Seoul P2 stars, I think they were warm white in the 2700 to 3500K temperature. They would have been much more appropriate to use in the kitchen with undercounter lighting than these 6500 to 7200K Cree Q5's. Another mistake....

So, when I redo this again, let's say this summer or fall. I will make the heatsinks much bigger, say in the 2 inch by 2 inch area and maybe a fin or two also would be OK and diffuser lenses unless I can find something else that diffuses even more. I will try to experiment with the cheap flourescent fixutures and see if that makes them a better choice too. I wil also use a warm white color too. I like the higher temperature colors for general lighting, however, I will shoot for 3500K for undercounter stuff.

Hope this saves someone from making the same mistakes I have, although for now, I like the concept and results. Now I need to fine tune this stuff.

Bob E.

 

[SafetyBob]

Time for a little followup. I was really not happy with the incredible lighting from the Cree's. It was just so narrow that it was not as satifactory as I wanted.....or should I say what the wife wanted.

My search brought me to Lowes and to the lighting dept. I went there searching for a very small flourescent fixture (cheap too) that I would just simply slap some Seouls (USWOH) into. What I found was a nice all metal halogen fixuture that swiveled and had nicely frosted glass. The display units looked horrible as lighting goes, but as a fixture, they seemed to fit the bill exactly. Since this was an emergency, I paid the price and went onward out the door with two fixtures. If I would have had the time I (and you too) could have easily made these fixtures out of simple sheet metal and some time. A small shear and brake would be required. I have a neighbor that has these so I need to get busy once it gets warmer.

Don't laugh or cry to bad when you see how simple this is. Here is the fixture partially torn apart.

http://i225.photobucket.com/albums/dd94/reverding58/100_0571.jpg

Here is what I did to my Seoul stars. Simple, simple, simple.

http://i225.photobucket.com/albums/dd94/reverding58/100_0572.jpg

I did not show you the epoxying of the starts to the reflector. Will try and get one in the next couple of days. It did take alot of epoxy because there was quite a valley to fill. I used Artic Allumina two part epoxy.

Study the completed redo of the project carefully. You will note from the picture you cannot really make out the individual leds due to the frosting of the glass. And they swivel in order to aim your lighting as you wish. Wife much happier with this setup. The cree setup would have been perfect to light up artwork or something on a wall.

http://i225.photobucket.com/albums/dd94/reverding58/100_0573.jpg

Hope this helps someone out.

Bob E.

 

[Mash]

Thanks for the write up and all the details!
I completely understand you regarding the cool tint. I find it awful for domestic living area use, makes me feel Im in a hospital! Some have suggested that using one red LED would make things more palatable. I've also experimented with gold reflector sheets which also warm up the tone a lot. As a quick and dirty test try using cut photographic filter sheets over your lenses and see how it goes.

 

[Gene43]

That is really cool. I like it!

 

[moon lander]

nice work! dont you love it when the wife actually wants you to buy leds?

i had previously done under cabinet lighting, but i wont link to that thread, since it was my first project and was mostly me asking things like "why does it need a heatsink?"

in the end, after much advice from the more experienced CPFers, i ended up with 2 aluminum strips 18"x2" maybe about 1/8" thick, each with a bare WH Q5 driven at 600ma from a 9volt ac-dc adaptor and a few ohms of resistance.

i like the WH tint alot, it is warm enough for me, more on the yellow side. since the cree has a narrower viewing angle, i left them bare and they illuminate the counter top very nicely.

i settled on 600ma because thats the most i can run them at before they overheat. next time ill use larger heatsinks or a third LED, but to be honest they are bright enough as is.

 

[SafetyBob]

Moon lander, you were the inspiration for all this on my part anyway.

I didn't realize the Cree's put out such a narrow beam until after I built it and then read about it here a few days later. I still don't know what I will do for actual undercounter in the kitchen. I think it would be nice to have a dim function, but really, why? When I do a small room that has our espresso machines in it, then I will know. As posted elsewhere here, I will just epoxy Seoul starts (unless I get warm Crees) to the base metal of the flourescent fixture I am modifying.

I am planning on getting some aluminum like you had and putting it in the same fixture I am modifying and seeing what happens to the light when the leds are against the top or base of the fixture and then what happens when it is almost against the white plastic lense. I think that will be invaluable information for us all. We would then have evidence as to how to quickly and effectively change out our existing fixtures with leds.

Bob E.