Wednesday, March 20, 2013

Surface Mount LED As Bulb

I walk the light bulb and recessed lighting rows at each visit to Home Depot, looking for something new. I don't know where else to see emerging LED technology. Yesterday, I picked out an example of a bulb-form LED that may fully reveal the light. There may be other LEDs for sale with full reveal where mounted in a can, but I don't yet see them. Salespeople don't understand my interest.

Knowing I would only test this light, I bought one that had been cut open. 

Marking resembles that of now-gone T91. Same wrong 75 watt incandescent equivalence. 
This is made in Mexico, for Home Depot, with bar code 74340 00111, and model ID 409 440.

I paid $24.97, relatively cheap. And, it is available now. But, beware loss of light where this fairly short bulb is recessed in a can. A short can might display all light. Much is lost as with all flood bulbs, where the bulb is deeply recessed.

I admit uncertainty what is under the glass dome. Surely it is a flat array of LEDs, that are fully displayed, surface mounted, if the glass projects from the ceiling.

 14 vs 14.5 watts power draw, 800 vs. T91 at 750 tested lumens.

LED bulb on the left, Philips EcoVantage 100-watt equivalent incandescent on the right. I'll give the LED Brightness Number 7. That's from accepting that stated lumens on a package are correct, and a standard of B6.7 for a straight-on 750 lumens 6" Glimpse/ T91. Then 800/750*6.7 = 7.1. 

Start with definition that a 100 watt incandescent with all of its spilled light, is B4. The incandescent is truly a point source, the bygone concept of an electric candle. Then, know that  narrowing a light beam is generally not helpful. Let it fall straight down, or perpendicular to an illuminated surface, without focus. I judge that the LED flood has a flat plate of diodes on the plane backing the frosted lens. All light is revealed.

Here a 600 lumens T47 is at the right, propped-up over the junction box and more-distant from the wall. B7 vs. B5? Same color temperature. I have guessed at 82% light transmission with the recessed diodes of the T47. 

0.82 * 600/750 * B6.7 = B4.4. Not B5? I admit here that this side-by-side comparison does not discriminate against recession of diodes, light at periphery not revealed. Official definition of Brightness Numbers as task illumination, will have complexity. I'm a little glib. Those applying lumens as brightness measure are irresponsible, perhaps willfully placing disadvantage in plate LED packaging. There is irresponsibility too, in not rating a bulb in a needful fixture that blocks revealed light.

All observed lights here are powered through a Cooper D106P dimmer, full-on. Buzzing? Yes. I haven't learned to rate noise, but here is a try. If T47/ T67 is level 10 on a linear scale, the LED bulb is 5. A 6" Glimpse is 3.

At end-October 2013, this post is edited as I update all of my blog posts, to replace phrase "plate LED," with phrase "surface mount LED." Phrase Plate LED is confused with license plate lighting, and is not accepted elsewhere as a brief statement that the luminaire may be wired directly into a junction box. In my definition, a plate LED is surface mounted, not recessed for foolish styling reasons, to look like a can-mount downlight. Can-mount downlights were a consumer adaptation of theater downlighting, where upon a black ceiling, there is nothing bright to divert attention from a stage. In any circumstance other than a stage center, there has never been a bit of virtue in recess setting of a light. It has been quite disastrous in our waste of the Earth's ready fuels, that many have loaded their can lights with bulbs that are simple point sources, with no reflector bouncing to usefulness, the light that otherwise does not beam downward; all such light and heat energy, totally wasted. Look for all content of this paragraph, and more, in a new blog post under construction. While I edit out the phrase LED Plate Light, I retain the label, temporarily. "Labels" are noted at the bottom of all blog posts, for collection of related topics of interest to a reader.

Friday, March 15, 2013

Looking Inside A First-Version 6" Glimpse LED Light

As a contractor, I have installed Glimpse LED lighting, proudly and with confidence. I have reported two failed lights in about six dozen experienced so far. Both were with the initial design of these lights, I will call Glimpse 6A.

6A is on the left. 6B, the only revision I am aware of, is on the right. 

In the 6A failures, both were in the rather flimsy wiring. In one, the ultimate DC connector at the metal back, came off in the necessary step of squeezing and uncoupling the little black quick connector. Resetting the connector receptacle half with epoxy didn't restore electrical contact. In the other, the plate and its connector are good, but something is wrong in the two-block power converter. I can't ignite the light by wiggling wires, but surely the lost connection is in the wires, not inside the blocks.

I have at last drilled out the three posts securing the lens to the plate, of the light with the failed connector. The posts are held by Starlock fasteners, removable only by destruction.

There is an array of twenty nine little LEDs, and surprising hand marking. This light was manufactured in June, 2011, early in production, where first sales were in September, 2011.

A wet white grease thermally couples the diode plate to the metal body of the light. 

I won't throw this away. I have offered it to a friend, who will solder on new leads, and run it in a 24 vdc circuit. There is so much good workmanship to be honored. This is so much more repairable than an iPod. 

Here is the back-side view of a 6B Glimpse light:

I won't ruin a good light by detaching the lens. Yet,  I am able to make some comparisons to 6A.

The LED array is quite different, probably brighter and fewer diodes. All LEDs fit on a circle the diameter of the power block. Note four oval half-inch holes, where you can reach through and touch the inside of the lens. In some installations these holes might admit bugs. In a perforated can light or poor junction box, light may show in an attic floor or dark ceiling cavity, a magnet to bugs. Holes for ventilation? I don't think so.

At 4/30/2013, edit for the text now maroon. Some LED lights do not attract bugs. I can't remember a bug ever flying at these lights. I must do and report on, some careful observation.

I wish LSGC would promote public excitement about these lights. A sleepy marketing process through commercial distributors has failed them. Buyers will not accept multiple markups of thirty percent, in any consumer product. We need these lights, at lowest-possible cost, in very large quantities. In deserved frequent design upgrades, let there be trial of full-spectrum lighting, with a distribution of phosphor colors. (Is it simply variation in phosphor thickness?) Where a light will long outlive a cat, it should be of correct color. Wiring now as DC must be no big deal, allowing full control of humming complaints where dimmed.

Sunday, March 10, 2013

Review, Home Depot/ CREE T47 LED Disk Light

T47 LED disk lights still are not sold at my neighborhood Home Depot. Another store in Portland, Oregon, had several on shelves and in a display, with no fanfare.

The T47 and T67 differ mainly in rim diameter.

Inside, they have identical LEDs with 2700°K phosphor.

Identical LEDs are confirmed by the power draw, each at 12.5 watts without dimming.

The lumen number difference is real, where more-foolish diffuser angle throws away more of the available light with the T47. If the T67 is Brightness Number 5, equal in brightness to 125 watt incandescent, the T47 is 600/650 times B5, or B4.6, 115 watt incandescent equivalence. The steeper diffuser (same depth with smaller diameter) throws away another 8% for total of 18% efficiency loss, in the vanity of recessing the diodes. I now call the alternative lighting, not recessed, Projecting Planar Lighting.

With identical diodes and drivers the lights have identical and unacceptable hum, where tried with a dimmer (Cooper D106P tried). I wonder how many T67s and T47s have been shipped from China, with such degraded value where their brightness calls for dimming in most installations. How stupid that we don't make these lights within local markets, where error may be correctable, in limited trial production. Stupidity is accused against investor forces welcomed by government, that reward, not punish, export of jobs. Perhaps there is an energy loss in all stupidity, here delay of conservation efforts.

I have no use for these CREE lights despite some cute features as noted in T67 review. I have a T67 installed for a customer, over a kitchen sink, where the brown color temperature is noticeable, and the greater brightness of a 6" Glimpse is needed while working. I do like the clips that grab the ID of the found 6" can light. This can is missing features to pull up a Glimpse. Replacing a can light with a junction box is a hard sell, where the ceiling is not an attic floor.

Like Glimpse, the CREE lights include some wasteful hardware and are in elaborate and expensive display packaging. With the CREE lights it is  difficult to reassemble in packaging for return with the humming complaint. We need to greatly reduce costs in Contractor Packs of better LED surface mount lights. If used in a noisy environment or without dimming, even T47 or T67 already are a better value than any light bulb, including any CFL. It is so important that we get this right quickly for a weatherization campaign, and we are so close.