When is 25k hours not 25k hours?

I accept in theory, in some circumstances, GU10 downlights can have a limited lifespan compared to an integral version.

However the the reliability benefits of Integral really would have to be quite large to justify them.

I know they are easy to change, but many people can change a light bulb but not an integral fitting. So if one did go wrong the cost would be very large compared to £1.50 to replace a GU10 bulb.

Also I like daylight bulbs, a lot of people don't, with GU10s it is a few minutes to swap the whole house.

I can't help but think if heating is a problem there are better solutions than integral fittings.

That might be a capacitor dropper. Capacitor droppers are a potential solution on low wattage bulbs.

But regular designs like that, they do not take kindly to transients on AC supply. A brief transient can cause the light to "flash" brightly in sympathy, and excess currents in the LEDs, lead to their demise. I'm not sure what would cause a "flickering fault" in such a setup - the main dropper cap (polypropylene?) has most of the drop across it.

Paul

Get a 1W rated resistor and dissipate 1W through it and see how hot it gets.

In this case the size of the bulb and the type of fitting are the problem. The LED equivalent bulbs have not been designed from new but as a replacement to fit in an existing fitting. The only physical connections are two lugs for the electrical supply and therefore cannot be optimised for maximum heat sinking. This coupled with their small size and usually in housings that fully enclose the bulb (apart from the front) makes getting rid of unwanted heat from the bulb difficult.

Both LEDs and power supplies fail if they get too hot. In the very small bulbs there may be a couple of capacitors, a bridge rectifier and a few resistors all packed into a space much smaller than the top of your little finger. Often one of the capacitors is an electrolytic type.

In panel type lights that have been designed for LEDS. the LEDS are bolted directly to some metal-work. In many of the ones that I've fitted there has been been a substantial metal backplate.

In outside flood light fittings the LED designs are completely different from the previous halogen models. The LEDs are bolted directly to the metal housing which provides the heat-sink.

Existing fittings are designed for different operating conditions. They are designed to survive high operating temperatures and not necessarily to cool the bulb.

Downlighters designed for LEDs don't have replaceable bulbs! This is how adequate heat-sinking is achieved because the LED can be in physical contact with the metal of the fitting. It also allows the power supply electronics to be removed away from the LEDs so one is not necessarily directly heating the other.

Yes, don't use fitting with such small bulbs.

Capacitor dropper (red blob), bridge rectifier (not transistor) , smoothing capacitor (4.7uF, rated at 105 degrees C) and resistors acting as fuses, inrush current limiters and bleeds.

In article snipped-for-privacy@perry.uk, Roland Perry snipped-for-privacy@perry.co.uk> writes

I had the same issue with our extension. So up in the loft I carefully created a space in the insulation around each fitting. Then when boarding over I cut a circular hole over each bulb to allow the heat to rise. Covered the hole with mesh to prevent the inevitable.