Issue with bathroom LED downlights

[masamune]

Three years ago I had the bathroom redone and fitted four Aurora IP65 downlights with LED GU10 spots.

Something like these:
http://www.arrowelectricals.co.uk/c...-downlight-in-satin-nickel-240v-no-bulb-p2474

The GU10 LEDs started failing one after the other intermittently after a few months, mainly flickering and then failing. I had them all replaced eventually and after a few months some of them failed again.

In October last year I bought 4x Megaman 4W GU10 PAR16 240V, which I consider reputable and have used throughout the house. Either dimmable versions in the living room or non-dimmable fitted in two exterior IP65 tube lights. None of these LEDs have failed in over two years. The outside lights turn on every night and are exposed to all weather conditions.

The first "bathroom" Megaman failed in February and I had it replaced, I wanted to believe it was just a bad batch. But now two more lights have failed, within a space of a week. One is totally dimmed and the other one went off.

This is driving me crazy, it is just too coincidental to be attributed to the LED spots. Is somehow the bathroom moisture affecting the LEDs? It is not the ones above the shower going first thought.

Or is the bathroom circuit somehow causing this. I found that the work was carried out by the bathroom fitter, although at first glance wiring and connections appear ok. Shall I measure/test for potential issues?

 

[flameport]

What's above the bathroom? Piles of insulation over the light fittings?

 

[masamune]

What's above the bathroom? Piles of insulation over the light fittings?

Yes, it's the loft and a couple of loose layers of rockwool specifically over the bathroom.

But there is no heat generated by the LEDs and I have not noticed any moisture/condensation within the IP65 fitting (which also has a rubber seal around)

 

[flameport]

LEDs require air space to avoid overheating.
Fit these over the lights: http://www.wickes.co.uk/LoftLeg-Loft-Lid-Downlight-Protector/p/148851

 

[masamune]

LEDs require air space to avoid overheating.
Fit these over the lights: http://www.wickes.co.uk/LoftLeg-Loft-Lid-Downlight-Protector/p/148851

I was just about to edit to add that I have bought these but they are still sitting in the loft 2 months later

 

[ban-all-sheds]

But there is no heat generated by the LEDs

Au contraire, mon ami.

 

[masamune]

Au contraire, mon ami.

....meant to say "substantial" heat

 

[ban-all-sheds]

Well - that's an interesting thing to say, because:

LEDs do produce heat. In absolute terms, very little, that is true, but they are also very intolerant of heat, so the heat they produce is meaningful, significant, important....

What little they do produce has to be got rid of, or it will cause the lamp to fail. LEDs have a negative temperature coefficient - unlike a piece of wire which increases in resistance as it heats up, LEDs pass more current as they get hotter, which makes them hotter still, which makes them pass even more current, which makes them hotter still. http://www.luxdrive.com/products/what-is-thermal-runaway/ Keeping them cool is essential - it's why you'll see big heat sinks on many MR16-type LED bulbs

If you install your caps to provide clearance under the insulation (you may need to get some more insulation because of the extra distance it will have to travel) it might well solve your problem.

 

[ericmark]

What BAS says is very true, my bathroom is only room in the house where LED's have failed, in pods so easy to cool and 12 volt at 0.58 watt, once replaced they were OK.

So why is the question? I can only guess, I suspect in my case it was because they were very cheap, and likely because the large 200W transformer resulted in high voltage.

It is possible you also have a high voltage, which if combined with poor ventilation could cause the lamps to fail, there are two very different ways to limit current through a LED, one is a capacitor or resistor which is selected assuming the voltage and frequency is stable as stated on the package, the other is to use a electronic device which will allow a huge variation in voltage, typically 100 to 250 volt, these would likely last better, but normally are not dimmable.

I would be really interested to know the outcome.

 

[masamune]

Well it is definitely very useful to know and an interesting background on LEDs, I have fitted the caps now except one (see below why). For clarification my LEDs are standard GU10 @ mains voltage (230V).

I suppose it is difficult to ask for a replacement bulb before determining the cause now...

The problem with the overheating theory is that I had LEDs fail in the middle of the winter and my loft is only insulated on the floor i.e just above the downlight, not the rafters. Of course 200mm insulation was covering the fitting but it was really messy above the bathroom and there were some gaps. I wonder if the ambient temp of less that 5oC in the loft would allow for the LEDs to overheat.

The other observation that makes me sceptical is that my roof is overhung, so one of the four downlights is placed exactly at the corner of the vaulted ceiling in the bathroom. In the loft this translates to being just below a hip rafter (if I may call it that?). So there was no insulation over that tiny gap, it vents directly from the soffits around it. Also, there is no space to fit a cap to protect it.

That said, two of the LEDs went out a couple of weeks ago and temperatures in the loft were quite hot as it holds warm air in the summer.

I guess the best thing to do now is replace the bulbs and keep an eye on it to check if the caps help with the overheating theory.

 

[GoodDIYjob]

Interesting this. Appears very coincidental to my problem. I have 8 gu10 megamans in the kitchen in an open fitting and have had 1 fail in 3 years.

However, I replaced the bathroom gu10s on a 3 spot open fitting, with exactly the same megaman gu10s and over a shorter time about 4 have failed. So into second replacements in under 2 years.

They don't make the exact megaman any more but the replacement economy range items have lower light output lumens and less warranty. Maybe that is telling me something.

Reading your post and my experience I think they must not like moisture.

Edit: The megaman gu10s I used were the 4w par 16 320lm 246211 (last 3 digits depends on colour, mine were warm white) items now no longer available

Update 2: looking a bit closer at my fittings, my description was a bit generic. In the kitchen there are two banks of 4 spots on a surface mount arm. The bulb holder surround for these is enclosed for the first cylinder part of the bulb but all the rest is completely open air including the taper up to the lens.

The bathroom fitting is a surface mount 3 fitting spot, which is why I called it open (in open air). However, the bulb holder surrounds are more enclosed than the kitchen. They are like metal egg cups and cover the whole bulb. But surely, the bulb holders themselves being mounted in free air would act as a giant heat sink anyway for the minimal heat that seems to be produced....

 

[masamune]

Interestingly enough the caps have not helped, with pretty much under 10oC in the loft, another one just failed. This one failed quick, it started flickering and within a few minutes it was gone.

My Megamans are LR1204DGv2-WFL / 4 Watt / 210lm , which also appear to be very cheap now...

I think the heat abduction or lack of it is partly the problem but the main cause must be relating to constant exposure to moisture.
If the heat theory holds true, then LED units in my living room ceiling would get a lot warmer and fail. They are inside the plasterboard void, surrounded by insulation and carpet with underlay from above in a heated house. None of them has failed in over 3 years.

 

[Iggifer]

Interestingly enough the caps have not helped, with pretty much under 10oC in the loft, another one just failed. This one failed quick, it started flickering and within a few minutes it was gone.

My Megamans are LR1204DGv2-WFL / 4 Watt / 210lm , which also appear to be very cheap now...

I think the heat abduction or lack of it is partly the problem but the main cause must be relating to constant exposure to moisture.
If the heat theory holds true, then LED units in my living room ceiling would get a lot warmer and fail. They are inside the plasterboard void, surrounded by insulation and carpet with underlay from above in a heated house. None of them has failed in over 3 years.

Get yourself to screwfix, get some Enlite 5w lamps, bin the megamans and you'll be fine. I fitted 4 of these in my parents bathroom in some generic fire rated downlights covered with insulation about 3 years ago and they're still going strong.

We fit those lamps on a daily basis (or the integrated equivalent) and I don't remember ever having to change one because it's failed. BG and Luceco we've had multiple DOA/first 100 hour failures. 210lm for a 4w is disgraceful. The Enlite is ~500lm for 5w. You might not want to go that bright - and they do do a 4w but never used it so can't say how good it is, but even that's 420lm.

I think the fact they've got DOUBLE the lm/w ratio says something about the quality.

 

[GoodDIYjob]

Will give them a go, seem to be a little cheaper at toolstation at the moment cw Screwfix, for the non dimmable anyway.

 

[GoodDIYjob]

My Megamans are LR1204DGv2-WFL / 4 Watt / 210lm , which also appear to be very cheap now...

Yes, that is actually the same as what I've got, also on packaging is "(246211)". Mine must be a newer model though as mine clearly state 320 Lumen. 4W consumption. Anyway, as they fail out of the bathroom fitting, I'll now to try something else. I'm going to try those Aurora Enlites. If that doesn't work I'll have to go back to halogens. They were lasting as long, albeit with higher consumption.

Think I still have a stock pile of Halogen GU10s somewhere!