Downlighter advice needed

[Roger Mills]

1. About 20 years ago, I installed some downlighters in an upstairs office. Each has a 35w 12v MR16 bulb, and they are all powered by an electronic transformer. The downlighters are not fire rated, so I dutifully left a gap in the loft insulation around each lamp.

If I were to replace the bulbs with 4W LEDs - either mains GU10's with no transformer but replacement bulb holders, or 12v MR16's with a suitable transformer for LEDs - could I then safely cover the lamps with loft insulation on the basis that the heat generated would be at least an order of magnitude lower than before?

1. Having temporarily removed one or two downlighters to examine them, I've found that, with their sprung retention arms, they're a right sod to get out without damaging the plaster around the hole. Anyone got any tips for making removal easier and less destructive? It might be easier from above, but I need to do it from below.

TIA.

[Animal]

I would think so, 4w is very little.

Just don't make a habit of it.

[David Wade]

I would leave space. Whilst they don't produce as much heat, my feeling is LEDs don't react too well to it. I have one in an enclosed glass "difuser" and it seeems to fail every 6 months or so...

They are no easier from above. As some one else said just take care.

Dave

[nothanks]

I found that I could remove the bulb holder section (mine had "eyeballs") so that the outer ring stayed in the ceiling hole and the (much smaller) fire-rated LED replacement fitted into the outer ring. This saved messing-up the ceiling and also acted as a hole size adapter. Could you do the same?

[alan_m]

The problem with downlighter fittings not designed for LEDs is the lack of ventilation and/or heatsink. LEDs bulbs have electric components in the base of the bulb which don't like getting hot, nor do the LEDs themselves.

[ARW]

No.

It's impossible on some makes of light.

Got you fingers snapped as if they were in a mouse trap whilst trying?

[Animal]

Once you repair the edges with filler, paint on pva

[Paul]

Some application notes I've seen in the past, for fitting LEDs to pots, they show the pot being open at the top, for air movement past the LED. Of course, if the pot was meant to seal the ceiling space from warm moist air, you cannot easily do that, so the application notes are just silly. But, they're written by a company making LEDs, so what else could they do ? But make silly ideas.

Some of the LEDs with silicon carbide substrates, are claimed to "take the heat". It's the SMPS and the electrolytic capacitor in the base, that can't really take the heat. Most LEDs will fail because of the base electronics, rather than the LEDs automatically giving up. Some LEDs can have bond failures, but that's only certain types arranged like that.

Sometimes you see LED panels flashing on and off a couple times a second, and that's likely the SMPS. We see that here occasionally on the LED street lighting. They didn't do all the streets here, just a few main ones, and lots of the stuff my city does, are termed "experiments" so they don't have to pay to do the whole city that way :-) For example, a street near me, got a custom road-cracks repair, and that will be yet another experiment, involving the usage of silicon rubber (ugh!). Riding a bicycle on that stuff, is dangerous, because it wiggles like jello.

Paul

[Roger Mills]

Possibly, but I was planning on keeping the eyeballs so that the new bulbs could be angled, like the old ones. I was only planning to replace the bulb and bulb-holder - the latter being just a GU10 inline connector with a couple of wires. [The bulb itself is held by a spring-clip, with the large end sitting in a recess in the eyeball.]

If I did decide to buy complete new fittings - with a smaller diameter than the current ones, and use the outer ring as a size converter as you suggest, how easy did you find it to remove the eyeball without taking the whole thing down from the ceiling? And didn't the old spring clips and sticky-up bits get in the way of the new spring clips?

[nothanks]

It was fairly straightforward to get the eyeballs out. Once the bulb was removed it was apparent that the eyeball had two spring-loaded pins which ran in a groove, allowing it to tilt and swivel. The new LED unit has a much larger beam width so I haven't felt the lack of tilt/swivel (but it's a high'ish ceiling) - either check the specs and do the sums for your situation, or buy one and try it. The ceiling is lath'n'plaster, so fairly thick, but wasn't a problem.

(Mine were 12V (MR16?) so I had to remove the power supply)

[Animal]

IME led lamp failures are almost 100% due to a bad LED, flashing lights likewise.