LED: Longevity

[yeldogt]

I'm sort of a light freak .. always go a bit overboard with my lighting design/layout. I like the layered light "look". Previously, with incandescent, everything had a dimmer .. even the timed stuff.

When the CFL's started to get better and came w/ frosted covers we changed out most of the outdoor fixtures w/ lower Lumen output CFL's and just had more of them on ...more of the time. I have two weekend places -- both in very dark locations. So we have a lot of lights. One of my places is an old stone farm house and we have a light in just about every room that runs 24/7. None of these are dimmable bulbs.

So to my point. A few years ago we started to change out the CFL to LED ... The 60w = LED's are about 8w ... so even with 10-15 running it's not much to worry about. What I'm finding .... the LED bulbs are not lasting any longer vs the CFL's and the CFL's never made it even close 20k hours.

I replaced all the exterior bulbs at my beach house before the summer last year -- all have timers and run all night. Some are floods hidden in soffits others are in various wall and ground fixtures (all 110v) . So last weekend one of the soffit LED's was out. When I replaced it with an extra I had (same bulb) -- it was so much brighter .. I was shocked. So, I tried one of the wall lights with a typical A19 LED bulb (I had extra) ... same thing ... all the others are noticeable with a lower light output.

So ........other than the cost of running the bulb they are not giving me much. I can't have different output with a string of 8 wall lights -- all the bulbs have to match ........ never an issue with the 60w incandescent.

Back when we did the CFL's -- we switched back to incandescent on some with the dimmed wall lights .. because the CFL did not last as long as the dimmed incandescent. I would need a spreadsheet to figure out what -- if any I have saved over the years switching out all these bulbs. Some exterior fixtures are a pain to switch the bulbs -- lots of time.

 

[dogdog]

I have 2 CREE brand 60 Watt LED bulbs from HD and 1 Feit or sylvania that went bad....yea. But weird as it is.... all in the same rental apt, the ones in my own place are ok. So not sure about the common denominator if it is the bulb or the people....

I find the GE brand ones is brighter and better.... the light stick or something.

 

[ForceFed70]

That's one of the big differences between florescent/CFL and LED. While both loose light output over time, LEDs loose much more.

Combine that with the failure rates being much higher than advertised (50,000hrs my ****) and I still shy away from LEDs except in some very specific applications. My experience has been that CFL is still cheaper overall.

 

[American Locomotive]

The problem is those screw in Edison base bulbs all run way too hot. Many of the LED bulbs are running the LED dies well in excess of 100°C, some bulbs push them over 120*@#$°C. As a result, it heats everything else up inside the LED to around 90-100°C as well.

That in turn is hard on both the LEDs, and the driver circuitry controlling the LED. An LED at 40°C may last 150,000 hours, but at 120°C, that can be down to less than 20,000 hours. An electrolytic capacitor at 40°C may have a 100,000 hour lifespan. At 100°C, that's often reduced to just 5,000 hours.

 

[ForceFed70]

The problem is those screw in Edison base bulbs all run way too hot.

Yes, I've come to the same conclusion. Same goes for CFL lamps.

Classic example - some of my CFL's that have lasted the longest have been placed in outside motion light fixtures with no cover. Despite the very high number of on/off cycles - they tend to last the longest because they're able to keep cool.

 

[Platonic Solid]

I had a CREE 60W equiv medium screw base LED bulb in my foyer. The dang thing got so hot that the potting melted into the bulb. Having the LED driver right behind the LED array is the worst combination. If you want to realize 50,000 hrs. + you need to buy new LED fixtures, not LED screw base bulbs.

 

[yeldogt]

I have specified a few LED recessed fixtures in my new house. Figured they would be the ticket for spots that would stay on most of the time - now i'm not so sure. The LED modules are large with heat sinks ... they are extremely expensive ($400+) and I'm sure the LED module is most of the cost. But, if they start to dim in 5 years what good are they. At least with the MR16's it's a $8 fix.