Standard A19 format light bulbs, found today in most lamps and luminaires, are now available in LED versions that retail between $20 and $40 per 40-W- or 60-W-equivalent bulb. Some bulbs are dimmable, some not, and some only with specific dimmers. They all advertise 25,000 to 50,000 hours’ expected lifetime, based on three to four hours’ daily usage. If you use them appropriately and sparingly, you might expect your light bulbs to outlive you.
But why are the bulbs so expensive? Do they provide real value for the price? And why are some bulbs twice the price of the others?
In our scientific quest for answers, MuAnalysis Inc. tore apart five A19 LED bulbs: a Philips 60-W equivalent, at 12.5 W and 800 lumens, and 40-w equivalents from Feit, GE, Pharox and Sylvania. Our examinations of the five bulbs raised still more questions. (For the full report, go to www.muanalysis.com.)
Each of the bulbs comes in a specially designed package, unlike tungsten filament and CFL bulbs, which ship in nondescript shrink wrap. The fancy packaging adds to the overall cost.
These bulbs clearly are not yet positioned as commodity items; they are expensive and are expected to last. But the price of electronic gadgets has dropped so much of late that longevity is no longer the main concern. So why is a common light bulb more expensive to buy than a cheap digital camera?
Looks count in a category as simple as light bulbs, and each of the bulbs we examined has a unique appearance. For example, the GE bulb has a ceramic neck and fins and a glass bulb, and is more costly than those using plastic and metal.
All of the bulbs have a small printed-circuit board contained within the neck, relying heavily on large electrolytic capacitors and transformers. The reliability factor of LEDs has increased tremendously. But how long will electrolytic capacitors perform under such hot operating conditions?
All of the bulbs have a small pc board within the neck, relying heavily on large electrolytic capacitors and transformers.
The manufacturers are probably not counting on the bulbs meeting the specified life but rather replacing them in the future with cheaper to manufacture products. Or just counting on consumers to not follow up with early failure replacements, as we were trained to accept with CFL bulbs which failed to live up to the marketing claims.
I have two remarks:
1. 105*C capacitors are commonly used in PC power supplies and PC mainboards. They still die in much lower temperature than 105*C.
2. 105*C capacitors are more expensive than typical one (like 85*C). I don't think if typical LED bulb goes higher than 80*C, so why someone should use 105*C capacitors?
I guess problem is not in high temperature but capacitor quality.
If you develop a PFC LED driver, you can use the deramic cap instead of the E-Cap. The E-cap life time shrinks one half for every ten degree ambient temperature. We have been designed the ACDC offline LED drivers for the LED lighting and to reduce the BOM cost. If you are interested in the products, please check out the web site.
We design our products in the 700V process, so the 500V HV NMOS and the 700V Power MOSFET can be integrated.
Please send email to Phil.Lei@sqme.com.tw to find out more.
I just picked up your query about my design. Yes it is still an application but has no objection raised as yet. It applies to UK, Europe and USA. If you can tell me a little more about what you'd like to know I'd be happy to help. email@example.com
A concern that I don't see addressed is vibration. I have had a CFL blowout in a ceiling fan installation. I haven't seen vibration ratings for CFLs. I These board designs with the air-chassis electrolytics don't look to have reliability in a vibration environment such as a ceiling fan fixture.
I've liked this article as it has answered the same question I had: Why the LED lamps are so costly and I understand, more than electronics, the manufacturers need to do something on the heat management and the casing part to bring down the cost.
Like many of my fellow readers, I am also surprised to see the claim of high lifetime with the electrolytic capacitors in it.
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