LED strips outdoor with freezing temperatures

[Swake]

Does anyone has experience with IP68 LED strips performance in freezing temperatures? Do they keep working in the long run?

I'd like to permanently mount some RGB LED strips outside of the house. During winter time we have negative temperatures. Down to -10C  (14°F) en sometimes even somewhat lower and I'm concerned the strips would not be able to sustain this.
The LED strip would be mounted facing downwards in an aluminium (aluminum) rail along the walls at an height of about 30cm (1 feet). The power supply would be placed inside the house.

[matseng]

Looking up the Operational Temperature Range in the datasheets for a randomly chosen led from CREE it says -40C/-40F to +100C/+212F. The no-name leds in cheap leds strips might have a different opinion though, but most likely it would be in the same neighbourhood.

So the leds themselves would be just fine with a measly -10C.  Actually the leds gets brighter and more efficient at lower temperatures.  Then there are some current limiting resistors that will change their value as the temperature changes, but the base resistance tolerance of the cheap resistors would be much larger than the resistance change caused by the temperature drop from nominal +25 down to -10.

[tggzzz]

Does anyone has experience with IP68 LED strips performance in freezing temperatures? Do they keep working in the long run?

The LEDs will probably be OK, but they are the most reliable part. At least getting rid of the heat shouldn't be a problem!

For the strip, it will depend on the materials and techniques used in the encapsulation of the LEDs - and that likely to be dependent on the individual manufacturer and "grade" (if any) of the strip. If going for very cheap strips, they might be strips that the manufacturer binned as being substandard.

So, what guarantees does the manufacturer give?

[Psi]

yeah, id be more concerned about the solder joints cracking from thermal cycling than the LEDs failing.

Maybe LEDs on flat flex style boards would be better than the solid mount variety?

[Kjelt]

Ledbars are sold for supermarket refridgerators (-18^oC ) so no problem. The chinese outdoor ledstrips have this sort of jelly stuff put around it, I would test that first with a 50 to 100 cycles in the fridge to see how it behaves over time.

[Swake]

According to the specs -10°C is not a problem. However the specs are made in China too.... and that's the issue, how can I rely on this... even with reputable brands I would not rely on the specs alone for these strips as they just purchase some lot and rebrand.

The problem with the warranty is I don't want to have to hit it. The installation process itself takes so much effort that I do not want to have to start over or rebuild. It is not like changing a light bulb with an E27 socket.

[Kjelt]

Just looked at one of the led bars esp. Made for refridgeration, they state not to use above 25^oC. Probably due to the small aluminium carrier that is not enough of a heatsink for the 1W leds on it.
An isolated ledstrip will also have a max. Temp for operation but probably much higher.
If you want guaranteed spec. Ledstrips I could not advise you, AFAIK due to the chines ebay ledstrips the strips suffered extreme price erosion to the point that only the chinese build them.
Most ledstrips sold from western shops are the same stuff.
Only advise I can give you if you do not want to invest heavily is to buy one and try it, if after two years there are no visual and electric problems go to phase 2 if you by then still can buy the same strips.

[Zero999]

I don't think freezing temperatures will be the problem, especially only -10^oC which is not that cold, considering most electronics will be fine down to -40, even if they aren't specified that low.

What's the maximum temperature rating?  You may need to over rate this by 20^oC or more, unless they're in a very shady spot or never on in the day.

Is the LED strip UV resistant? UV can damage polymers, making them go brittle and opaque. If the answer is no, or it's not specified then they shouldn't be exposed to direct sunlight for long periods, whether on or off.