Author Topic: Eternal Lamps  (Read 823 times)
flyoffacliff
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Eternal Lamps « on: March 10, 2019, 11:30:37 PM » Author: flyoffacliff
Anyone ever have a lamp that just won't die?

I bought these CFLs (https://www.amazon.com/gp/product/B0030CW3C8) years ago, and put one of them into service in the spring of 2015 in an outdoor post light. Rated for 6,000 hours, and it's now run over 17,000! I know it only cycles once per day (although it used to come on during the day sometimes before I replaced the PC), and it's a dimmable lamp running at full brightness all the time, maybe that makes the difference.

Also, one of the few incandescent lights in my house is a recessed light. I remember my dad replacing the lamp when I was in grade school about a decade ago, and I remember the box saying "double life", and it's sure lived up to that title.

Also had some very old lamps on a rotary dimmer in a bathroom, which I think extended there life, because they got turned up to full brightness slowly. You could see the filaments sagging a bunch between the supports! I used to set the dimmer as low as it would go and look for "hot spots" along the barely glowing filament.
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Medved
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Re: Eternal Lamps « Reply #1 on: March 11, 2019, 02:07:12 AM » Author: Medved
It is not eternal by far. Just the 6000hour rated life is not dictated by the hours alone, but by the switching cycles.
So the 6000 hours means 2000 starts life (and that means just 50% failed lamps). Because you operate it likely with 12hours/start, with 2k starts it means 24khour life expectancy in your service.

The thing is, these cheap CFLs are designed to be start cycle limited (because cold cathode starting, so the circuit remains simple, the electronic gets the killing stress only after the tube is wearing out). So to achieve reasonable rating, they have to design the cathodes so they are rather robust against wear. That means when not stressed bythe frequent starts, it has all the expectation factors to last the 24khour. So when not screwed up with the assembly quality, it will last so.
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