| T O P I C R E V I E W |
| pfrank |
Posted - 05/14/2012 : 09:13:22 AM
Like others, I've encountered the issue that when attempting to use a controller on LED rope lights, the lights never go completely out -- just a low dim. For the application where I have the rope lights (above kitchen cabinets) I don't mind this, as they "disappear" during the day and provide a soft glow at night even when in the off position.
My questions: Since the LED rope light won't dim to a full off position, is it safe to leave these lights permanently on? They're supposed to last 100,000 hours (11+ years) and there is no heat from them since the're LED, so I don't mind... just want to be safe.
Thoughts? |
| 10 L A T E S T R E P L I E S (Newest First) |
| Geo |
Posted - 05/23/2012 : 06:40:41 AM
Out of curiosity I calculated, using the HDBK 217 model, the failure rate of an LED - the type used in rope lights. It comes at a whopping 2.208E-3, which translates into 4.529E8 hours MTBF (mean time between failures) or 51,700 years. If the rope contains 100 LEDs and a failure of any one makes the rope useless, then statistically the life of the rope is 517 years. Even if we add some unknown environmental factors, chances are we won't live long enough to see it die except due to a damage. |
| Geo |
Posted - 05/19/2012 : 11:32:52 AM
BTW, where does the 11 years life span come from? When the first LEDs came out in the seventies (by Monstanto) I built a couple of projects with them. They still work! |
| Geo |
Posted - 05/19/2012 : 11:29:55 AM
I've also had them for 10+ years outside without a problem. I did some work in Barbados where they have them all over the place, also around pools, exposed to the sun. I heard no complaints. |
| stusviews |
Posted - 05/18/2012 : 10:50:09 AM
More that two years outdoors in sunny SoCal. |
| oberkc |
Posted - 05/18/2012 : 09:56:30 AM
quote:
Citation needed.
Agreed. My experience with rope lighting is contrary to this. I have rope lighting that is outside (no direct exposure to rain/snow or sun) and has been so for over ten years without any apparent problems with the rope plastics. Furthermore, I am not even sure that degredation in the rope material would be cause for failure of the LED string.
Like many physical devices, however, life is very dependent on the environment. I would imagine that the biggest factor would be UV rays from the sun. |
| Tfitzpatri8 |
Posted - 05/17/2012 : 6:53:26 PM
Citation needed. I haven't seen any safety issues with LED rope lighting or any guidance to remove them after any particular number of hours of service on a dimmer. Where are you seeing something different? |
| mistrip |
Posted - 05/17/2012 : 6:38:04 PM
No, it's not safe. The LED can last 11 years, but the materials such as the rope plastics, can't last for a long time. |
| Sammer |
Posted - 05/15/2012 : 09:01:27 AM
quote:
Originally posted by Geo
LEDs DO generate heat just like any other load. The biggest problem with LEDs intended to replace incandescent light bulbs is how to dissipate their heat. In your case, however, because the current is quite low, the LEDs will not heat up noticeably above the ambient temperature.
There is a reason for some confusion here. As efficient as LEDs are they are not 100% efficient so some electricity is converted to heat. However LEDs unlike incandescent or fluorescent lights can not radiate heat so another way must be found to dissipate that heat (the LEDs must be cooled) or the life of the LED light bulb will be greatly reduced. |
| Geo |
Posted - 05/14/2012 : 3:35:38 PM
As mentioned many times here, just a small incandescent light or some other small load in parallel with the LED will get rid of the glow.
LEDs DO generate heat just like any other load. The biggest problem with LEDs intended to replace incandescent light bulbs is how to dissipate their heat. In your case, however, because the current is quite low, the LEDs will not heat up noticeably above the ambient temperature.
Incandescent light bulbs have limited life, usually around 2,000 hours, but that depends on how much current flows through them. For example, if you put two 7W bulbs in series, the total power consumed will be 1.75W and the life of the bulbs will be around 50,000 hours.
I'm using quite a few dimmers in my home - by reducing the lights' voltage even slightly, the lower light level may be imperceptible, while the power drain drops at the square of the voltage reduction and the life of the bulb increases significantly. |
| Tfitzpatri8 |
Posted - 05/14/2012 : 10:32:45 AM
As you no doubt already read in those other threads, small LED loads don't put enough of a load to overcome the 'load sense' feature on plug-in modules. To make the dim glow go away, or use a wire-in module or switch that doesn't have that load sense feature.
If you like the glow and the load you are using doesn't flicker, I see no downside to just leaving it be. |
