Tuesday, April 14, 2015

An LED "Fluorescent" light for the kitchen

Years ago, we took out the normal Fluorescent light fixtures over the middle of the kitchen and put in a skylight.  For kitchen lighting, we put shop lights on top of the upper kitchen cupboards, pointing up, so that the light reflects off the ceiling and down into the kitchen.  The shop lights each have two 4-foot fluorescent light bulbs.   Every now and then, I have to replace the bulbs.  Power is supplied by outlets that were added in the walls above the cabinets and controlled by the standard 3-way light switches from before the change.

Lately, one of the fixtures has not been working well.  When we turned on the lights in the kitchen it would not come on.  Or not for a while.  Or not until I went and hit the fixture lightly a couple times.  I replaced the bulbs, but it didn't get any better.  So it's probably not the bulbs, but the fixture.  Now the fixture itself is little more than a switch, some wires, and a ballast.  The ballast is apparently a transformer, and sometimes they go bad.  So I need to replace the ballast.

I've replaced ballasts in the past.  It's not easy work, and the replacement ballast typically costs about as much as a new fixture -- $20 to $40.  So there is really little economic reason to replace a ballast; better to get a new fixture.  So, off I go to Home Depot.

Of course, the current fixtures, even for something as mundane as a shop light, are not the same as they were decades ago.  And we are in the transition from incandescent and compact fluorescent bulbs to LEDs.  I have a small flashlight with 27 LEDs that is really bright.  If only they could do that in an even bigger fixture.  And they can!  I can get a new fixture that is roughly the same as the old one in size, but with two LED strips instead of two fluorescent bulbs.  In theory it will last forever (or at least decades), so no more bulbs to replace.  $130.

While I was pondering this, an employee of the Electrical/Lighting department comes up and asks if I needed any help.  I said I was looking to move over to LEDs from my current fluorescents, but that what "they" should really do is develop a drop-in replacement for a fluorescent bulb that used LEDs internally.  And the employee said, "They did!", and took me over to a separate stand with a bunch of triangular cardboard boxes.  Each box had a replacement bulb from Toggled.

But it is not really just a drop-in replacement.  Rather the LEDs run off regular 120V 60-cycle wall plug power, so you have to remove the ballast.  Which is perfect for what I need -- the ballast is my problem!  And I figure I know enough wiring to be able to make the necessary changes.  So I buy two bulbs.  $35 each.  Not cheap, but less than the cost of the new LED fixture.

We start then with the light fixture and the two new bulbs.

 The first thing we do is open open of the boxes, to get the instructions and anything else.  The box is not easy to open -- I guess it was designed for sturdy transportation, but inside is the bulb, the instructions, a sticker, a couple of wire nuts and ends for the bulb -- duplicates of what is already in the fixture (apparently there are cases where the existing ones may need to be replaced).

The instructions say to open the fixture and cut the wires to the ballast, which is what I was expecting.  The instructions say to just leave the ballast in place, but I don't see the point in that -- it no longer serves any purpose but to add weight, so I removed it completely.

Now things get a bit more complicated.  For regular fluorescent bulbs, the reason there are two ends, and it does not matter if you put the bulb in one way or the other, is that both ends are powered.  For the LEDs on the other hand, it just gets power from one end -- the other end becomes just a way to hold the bulb in place.  The instructions have a little diagram.

The important thing to notice here is how the wiring for the LED bulb is just a simple power and ground situation.

Understanding that makes it a bit easier to modify things.  I can go to the far end of the fixture and just clip all the wires off.  And the near end can be substantially simplified from what was there.  Power comes in on the black wire, goes to the pull-switch (which we don't use) and then is distributed to one side of each of the two fixture lampholders.  The other wire from each lampholder is brought back and tied to the white (ground) wire.

In our case, the black power wire goes to a yellow wire nut to a yellow wire that goes to one lampholder.  A white wire right next to it carries the power over to the other lampholder, and then another white wire (from the other side of the lampholder) brings the ground back.  The lampholder with the yellow power wire has another yellow wire that takes the power back to another yellow nut with the white ground wire, to complete the circuit.  If I had to do this for show (instead of just for function), I would would change the color of the wires to make it clear which are power (black) and which are ground (white).  But even with the confusing wire colors, this is pretty simple, and no one should see it again for decades (if we are lucky).

Since I can, and just for over-kill, I both used the wire nuts and soldered the wires together -- solder them first and then put the wire nut on -- so the connections should be very solid.

Once the wiring is done, I can put the cover back on and install the two LED bulbs.  This is more difficult than necessary.  The LED bulb only has one side with lights (why have lights on the back side?), so it has to be rotated correctly to get the lights on the outside.  And it only gets power at one end.  The bulb has two aluminum strips along the side and engraved in the aluminum at one end is a suggestion that that is the end which needs power.  A more obvious marking would make it easier to be sure the right end is being put where the power should be.  (But, presumably, putting it in backwards just means it would not work; it wouldn't hurt.)  And with any luck, I will probably never replace this bulb.  (Of course, by the time I have to, I'll have forgotten all about the fact that power comes from only one end).

and then turn it on to see that it works.

Once it is back in place, I can test it out with the normal kitchen light switch and see how it works with all the other kitchen lights.

It seems to take just a moment to come on, but no more than the old fluorescent bulbs did.  The light is very bright.  I had a choice of 3 different "temperatures" for the bulbs -- 3500K (Neutral), 4000K (Cool White), or 5000K (Natural Light).  I choose the 5000K (Natural Light) and it's a bit brighter and less "orange" than the other fluorescents we have in the kitchen, but I would probably change the others to be this color, instead of going the other way; I might step down to the Cool White 4000K color.

This all took about 30 minutes.  Check back in 20 years to see how long they last.

Did a second kitchen fixture in May 2015.

Changed out one of the garage light fixtures in July 2015.

I had been having trouble with this light fixture for months; it was not coming on when I flipped the switch, but flipping the switch repeatedly would eventually get it to work.  Now it turns on every time.  Seems like there is a slight delay before it comes on, but it does come on consistently.  The 5000K (natural light) works really well in the garage.