Since the fluorescent tube located in my kitchen soffit wore out, I decided it was time to upgrade that part of the lighting system with newer technology, and the availability of inexpensive line voltage powered L.E.D.'s seemed like a logical choice, given their new- found reputation for high efficiency with low power consumption, and remarkable lifespan.
Step 1: Determine the Illumination Needs
Old school thinking was in watts, but that's a very inexact way of determining modern levels of illumination, a better method is to think in lumens. Charts indicate lumen levels in square feet or meters by room designation or function, such as kitchen (general): 300- 400, kitchen (task): 700- 800, etc. I chose a level of 400 lumens as the area I wanted to light up is only occasionally used for tasks. Pulling the ballasted fixture and installing a receptacle for the power plug was all I needed to do for the new makeover, and goodbye to the 1980's look.
Step 2: Determine Fixture Style
I like the "puck' design as it is very easy to install- just cut a round hole 50- 55mm (2"- 2 5/16") diameter, either with a hole saw or saber saw for mounting. It is held in place with spring clamps, and can be rotated and swiveled to put the light cone where needed. Each fixture is rated for 90 lumens x 5 = 450 total lumens. It should be noted that this output will lessen over time, but not as dramatic as incandescent or fluorescent, so a little extra makes good sense.
Step 3: Verify the Calculations
I constructed a lighting gantry that replicated the height above the countertop- 48" (1220mm), thus allowing me to determine the best spacing for optimum light convergence by mounting the fixtures in plywood tabs and shifting the center distances until I felt comfortable with the result, which turned out to be 18" (457mm). I let the array burn overnight just to monitor the heat- none, and state of current- stable.
Step 4: Fabricate the Mounting Panels
Since I had an odd number of fixtures to mount, a simple 50/ 50 split of the length would have made an awkward middle position of one of them, so I broke it out into 3 panels which I butted end to end, found the center, and spaced out the requisite center dimensions both left and right. Two inverted "T" supports cover the joint lines as the panels simply drop in place, and I made use of some scrap 5/16" (8mm) CDX plywood. Holding the plywood at an angle incident to the light discloses any surface imperfections, which were filled and sanded level with joint compound. They were then given a coat of primer and finally a finished paint job.
Step 5: Some Electrical Data
The ballast labels shows the normally expected current draw to be .55 amps, and the 1st meter reading is with the dead fluorescent lamp installed. The second reading is the total power consumed with all 5 L.E.D. fixtures powered up, about half that of a dead lamp.
Step 6: Parting Thoughts
My total cost for this upgrade was $30, the other project materials were on hand. At 50,000 projected life hours, 12 hours a day (way more than I will do) gives a total of 4,167 days use. That's 11 years before burnout should occur, but by that time something else will have appeared that will probably make these seem like energy hogs anyway.