LED Lighting Primer – Part 3 (Tube Lights)

Beyond normal screw bulbs in our house, we’ve got a bunch of florescent tube lights. The primary lighting for the family room, workroom, and garage are tube lights, and are old enough that their flicker and hum is something I want to get rid of.

Unlike with screw bulbs, we’re now in a part of the lighting catalog where the major manufacturers haven’t showed up yet. So there are a bunch of options coming from people you’ve never heard of before. It means you won’t find them in any retail stores. As such I’ve been trying a few things to figure out what’s gong to work for me in the long run.

LED Tubes

You can actually get T8 LED tubes which fit in a tube light fixture. You can even get it at 3000K, so you can get a much nicer color than tube lights typically produce.

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LED tube lights

The results are quite good. These are at least as bright as what I was replacing, the color is better. The only interesting thing is that these are on the same switch as a couple of SlimStyle bulbs, and the tube lights are delayed in flipping on by about half a second. I’m assuming lag in the transformer / rectifier.

Installation is a bit interesting, as the LED lights actually have the transformer built in, only have pins live on one end, and just take raw 120V AC across those 2 pins. That means that for a florescent light fixture you are going to gut and rewire it to bypass the ballast, and cut off anything flowing to the far end. This is a one way conversion of that light fixture. All in all it took me about an hour to figure out what I was doing and solder the internal connections appropriately.

But this whole process made me think, once I was all done, I was basically just using the tube light hardware as a holder. Tube light fixtures aren’t exceptionally attractive, so while this is fine the one place I did it, I’m not sure I’d do it again.

Tube Light Tasks

In our home the tube lights are used in 3 rooms: workroom, family room, and garage. I installed the ones in the garage to make it a place I could work on projects after dark. We have a bunch in the workroom for starting plants in the spring. These are used largely because they are cheap, throw a lot of light, and were about all that was available at the time.

LEDs have way less design constraints. You are are starting to get some really interesting designs coming out of Chinese manufactures, now that selling directly to international consumers is a thing. One of my favorites are these 1/2 inch thick illuminated panels that give off 900 lumens with 12W. From what I can tell they are a minimalist package built around a high end CREE (yes the same CREE) super bright LED component. They come in a few different shapes, sizes, and light colors.

Mudder LED Ceiling Panel

Which looks kind of like this in action (taking pictures of lights is hard).

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For overhead bulk lighting in places like the garage, this is probably going to become my go to device. You do need to build a bit of a box for the unit to hang in, but it will still have a lower profile than the tube lights. They’ll also be instant on and not flicker.

Grow Lights

The other place lots of people (including us) use fluorescent lights is to grow plants. We have a small side garden mostly for early greens, peppers and tomatoes. Susan starts everything inside in March and we transplant to the great outdoors mid May.

chlab

We have a lot of science around photosynthesis now, specifically what wavelengths of light are used for these chemical processes. We’ve had that information for a long time, but we couldn’t do much about it until recently, because our ability to create custom colors was limited. You now can actually buy LEDs that nicely land inside those absorption peaks. I was planning on building my own light pods from scratch a couple years ago (I even have most of the parts) but never got around to it. Now you can buy it off the shelf.

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I got one of these to experiment with, it’s currently just pointed at some African violets until we need it for seed starting. Definitely a little trippy. What looks like imaging artifacts… aren’t. The red and blue shadows are really there in real life.

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We’ll probably need 4 total for the grow area we have. We’ll also need to put heating pads under the plants as these don’t generate any heat (the fluorescent lights did) and soil temperature is important to germination.

So the net of all of this is that I’ll probably end up replacing the rest of the tube lights that I have with LED panels (or some other more interesting LED fixture), and use proper LED grow lights for that task.

Design Constraints

By the time I had gotten to tackling the tube lights in the house I was beyond what I could buy at retail, so have been experimenting with some one off purchasing on Amazon.

But modifying that tube light unit really made me think about how many physical constraints have shaped our thoughts about lighting for the past century. The light bulb is a curious set of physics that is about running too much current through a tungsten wire that lives in an evacuated glass sphere so that it doesn’t burn out. Which also explains most lighting fixtures, as they have to be built to protect these lights, and vent the enormous amount of heat they generate.

A very similar set of constraints apply to fluorescent bulbs, with slightly different physics. The CFL was a very odd set of tricks to do what you needed to with fluorescent bulbs in the design point for the Edison light.

LEDs are going to change a lot of the way we think about lighting. If the Edison bulb was stone, and fluorescents are wood, LEDs are clay. A building material that can be reworked into all kinds of shapes and sizes natively. But I’ll dive into this all more in the next section.

2 thoughts on “LED Lighting Primer – Part 3 (Tube Lights)”

  1. I have a passing curiosity that is purely academic/technical (?): regarding the use of a heating pad for the plants, what is the energy use factor with the LED bulbs when the pads are in use?

    It’s clear that without the pads, the LED units would be at minimum par with the fluorescents, and probably better in terms of use, but including the pads, over time, is the energy use better still? My instant thought says yes – as the pads are at worst intermittently used, and the energy use is only factored in when on, but I wonder what the percentage is?

    It would be “amusing” (and sad?) if it was a break even – and the amount we are talking about is tiny to the point of incidental, but hey – I SAID it was academic 🙂

    Seriously cool visual on the plants though.

    BTW: Are you aware that my wife, daughter and nominal son in law (Fabian) all work for Selux, a lighting company in Highland? Fabian is product manager and responsible for getting a new LED fixture in place here in the US months before Germany – something that has not happened before!

    1. Honestly, it may use more energy, but it will be put in the right place. The lamp heated the air in 360 degrees. At best probably 1/3 of the flux was hitting the soil, so the soil impact was probably minimal. I’m going to try to build a feedback loop so it will just keep the soil at the right temperature(s) (just found this interesting table that will be helpful – http://tomclothier.hort.net/page11.html)

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