Lightimes Online News and Resources for the LED and Solid State Lighting Industry and its Supply Chain

April 3, 2008...Based on the 300% uptick in email comments we experienced in reference to our last commentary, it's fair to say that we hit a nerve by sharing the disappointing results experienced from some of our LED-based Christmas lights. The quick catch-up is that we subjected them to a little "slow to take them down" stress-test, and discovered a combination of corroded and non-interchangeable connectors, and several real live LED failures (at the packaged "lamp" level... it's unlikely the actual chip in there failed unless it was cooked or broken by package or design deficiencies). I wanted to share some of the comments with you all as they both reinforce some past points we've made, as well as to lay some groundwork that might help us glean some realizations for the larger solid state lighting industry.
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Dear Tom,

I pretty much agree with your findings on LED Christmas lights. This past holiday season I went nuts buying LED Christmas "everything". The 3-tree musical set with RGB globes and light show synched to the music worked well. It sat in my front yard filling the hearts of rush hour motorists with joy while they were stuck on my side of the railroad crossing. This is now packed away and waiting for Thanksgiving to roll around again.

The two LED deer and one 6-foot multi-colored LED spiral tree (brand names, from a major retailer) also faired pretty well, as did the 7.5 foot indoor pre-lit LED Christmas tree, purchased online. The LED strings let the whole team down, though. I bought LED strings, net lights and Icicle strings from both the same retailer (again, brand name) and a "big box" home improvement store (their own brand). Fortunately, I am can be both optimistic and completely cynical, so I kept the boxes.

All failed and for the same reason. None of them had any form of sealant at the point on the LED lamp housing where the leads exited. Water was sucked into the housings via capillary action. This then corroded the contacts; they rusted and the LEDs failed. All were returned for full refund, so no big deal financially to me, but it was a dent in my hopes of an LED holiday season and a hassle to keep going up and down a ladder in the depths of a Midwest US winter.

Lessons learned: I will have a tube of sealant handy next time and spend the time closing up the wire entry holes before hanging the lights. Also, it appears not to matter whether you save your money and buy generic from a big box store, or pay more for a name brand.

Just thought I'd share so you know you're not alone.
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Tom,

I feel your pain, brother. But unfortunately, the facts regarding LED Christmas lights are grim. Also unfortunately, they are probably the first experience most people will have with LED "lighting". The manufacturing process for LED Xmas lights can be described in three words: cheap, cheap and cheap. All manufacturing is in China and they use the lowest grade off-spec blue LED chips from Taiwan. (There is one spec - the chip has to light up when you put a voltage across it). And the assembly process is likely the lowest quality imaginable. No matter whose brand is on the box, they are all made in China with pretty much the same processes. I doubt if anyone is going to take ownership of this problem. To make truly good quality lights would push the price up so that no one would buy them.

You aren't the only one to notice. There was an article recently in one of the electrical engineering pubs panning LED Xmas lights.

I don't know what the solution is. Hopefully, when the Solid State Lighting Industry Trade Association gets up and running, it can try to counter some of the bad publicity and educate people on the difference between "bad" LEDs and "good" LEDs. But I'm afraid it will be "once burned, twice shy" for many folks.

By the way, I don't mean to disparage the Taiwan LED chip industry. They make a decent revenue from selling chips to China for Christmas lights. But even they would agree that these are far from their best products, and can be cheap because there are so few specs required. Some of them are actually quite good chips, but don't meet a voltage, wavelength, or other spec that a customer such as a cell phone handset maker would require. Others are not so good. I suspect it is the packaging, soldering etc. that causes most of the problems.
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Tom,

The series-parallel blocked LED strings sold as Christmas lights since the early 2000's that are based on Allen's/ForeverBright's patents are all prone to the same failure mode. Thanks for reporting about this mess honestly for a change. We've been saying the same thing for years and we were so sure that the direct-AC powered LED holiday lighting based on parallel-series blocking was doomed to fail from the outset that our commercial system was designed to run on DC using REAL UL1310 drivers, etc. from the start just like "real" SSL fixtures.

Imagine that. Hindsight is 20/20 for some of us who misunderstand what an industry leader actually is, huh? Its not about who sells the most or who hypes the most its about the products. When I talked to the early manufacturers of these holiday lamps long before most people had even heard of them I realized that it was a consumer hype driven joke. Still is.

The problem is, to do this thing right requires real LED drivers, attention to wiring runs, etc. that these direct AC powered consumer systems will never address. The same industry-damaging failures are being reported in other manufacturers holiday C-7 and C-9 screw-base "incandescent replacements" sold in the last two years. The battle cry for those cheap pieces of junk are "No power supply needed!"...God help us.

Again, nobody listens - nobody cares - they just go for what's cheap. You get what you pay for.

J.S. Callahan
Carpenter Decorating Co., Inc.
www.carpenterdecorating.com
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So there you go. The good news is that they shouldn't break due to the minor roughhousing that most light strings experience while you untangle them on the sidewalk, they won't lose the glass and leave the hot leads (a reindeer set me on my butt and triggered the GFCI a season back when I grabbed the leg with an exposed set of bulb leads), and they sure do use a lot less electricity. When they are truly as cheap as the incandescent strings, maybe as soon as next year, we'll have something the probably fails at about the same rate, and saves us a noticeable amount on our utility bill. Replacement "bulbs" are included, so what the heck.

The danger of all this is the damage to the overall reputation of SSL for general purpose applications. Especially when you might have a GE, Osram/Sylvania or Philips selling holiday light strings or flashlights that are created by their consumer products division rather than the actual lighting division. A little research has revealed that it is almost assured that even the brand name products were neither concepted, designed, spec'd, supplied or marketed by the lighting side of the house. It looks like none of those big names, who also have a mix of LED manufacturing or packaging capabilities, sell those types of packaged lamps. It's very unlikely that they even made the die (chips) that were used in their own brand of light strings. The problem, of course, is that the consumer doesn't know the difference. When they see any of the big 3 promote SSL and weigh that against the experience they've had with what turns out to be a sister division's poorly engineered product, the industry begins to gain a reputation that could take a while to undo.

Hopefully, headquarters will be taken to task by the lighting divisions for letting the consumer group produce mediocre products when it is actually the lighting divisions' reputations are on the line. A little ownership by the leaders and things could likely get on a better course very quickly.

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