At home we have 2 outdoor motion sensors that drive the outdoor pathway lights. However, the lights are non-dimmable 6W LED GX53 bulbs, and half of them died within 2 years of use. I suppose because of frequent on/off cycles.
I am now wondering how I could smarten the outdoor pathway lights and at the same time lengthen their lifespan. Would it make sense to use dimmable lights and finding a way to smoothly power on the lights (even at low dim level) to this end?
LEDs should not suffer fron on-off any more than any other electronics; they are electronic too. Likely you just had poor quality bulbs, this happens sometimes. More specifically, LEDs themselves are perfectly fine but their power supply died.
Try buying a different brand from different vendor.
I also believe the power electronics died prematurely.
The main problem is that these lights are mounted on the façade and are exposed to weather. So I guess humidity and low temperature may have killed the lights.
I may have to replace the current lights with weather proofed light appliances.
The LED lights have a GX53 fitting and are mounted in an outdoor proof fixture mounted on the façade. In replacing the defective lamps, I noticed no humidity at all in any of the fixtures.
My reasoning was that, if I could run the lights at lowest power when it’s cold, then I could avoid thermal shock in the fragile power circuit (which basically converts 230VAC to 5VDC).
I could then write a rule that would manage light intensity (dimmer) depending on how “cold” the lights are. I could factor in outdoor temperature with the last time the lights were switched on, for instance, in an OH rule.
I don’t believe a dimmer would be able to solve the problem. LEDs are not incandescent, traditional dimmers for them are just a legacy thing, and dimmable LEDs have hard times pretending to be incandescent. That’s why they don’t dim so well; dim only halfway down, then start to visibly blink, then completely shut off.
If you imagine a typical AC sine wave, the dimner works by interrupting the power faster than a half period completes. As a result, sine wave turns into somewhat triangular “spikes”. But electronics really doesn’t want that,it wants a nice constant power supply. Yes, the bulb has a rectifier and a big capacitor to keep up with that. And shorter power bursts mean it actually has to draw more current to keep the cap charged. Increased consumption also causes a buzzing sound in the dimmer on low settings.
So, legacy AC dimmer is not a solution.
I agree that a simple legacy AC dimmer won’t work. I’m more looking into electronic dimmers that will cut the phase, either in the up or down slope.
No, a dimmer is not working. The LED runs on about 2 - 2.5 VDC (depends on the actual material compination used and very much on temperature). Your mains AC is transformed and rectified to obtain a DC supply voltage.
The cheap way is to use a resistor to reduce the voltage to the required drop at the LED. The expensive way is to use a constant current source or sink to supply.
To “dimm” the LED, you use PWM (pulse width modulation), that is a very fast switch on/off of the LED which you can’t see with your eyes.
LEDs get destroyed from local overheat and a “thermal runnaway”. The thermal connection of the semiconductur die to the heat spread is the key for lifetime. Design and process quality have a huge impact on this. Thermal cycling + humidity and frost may have a damaging effect on the thermal connection.
Well, it’s impossible to qualify such a product as a consumer. So you need to put your trust on brands.