LED failure

MX5huggy

I replaced 16 50w MR16 12v spots with Crompton 5w Led. 2 years later one has dimmed (when filmed it has a flashing effect when played back) and one is flashing on and off like a disco light. Both have cracks in the back of the lamp. Have I messed up by not considering the transformers? Should I try to get them replaced as they are not lasting as expected? Photos of the lamp, transformer and unknown connection block between the two.

Cisco001

I don't think you need to change transformer, your lamp stated it works for both AC/ DC.
However, i don't know the reason of your broken light.

almillar

The transformer is capable of 4.9A and if it was happily running 50W halogens, and has worked with the LEDs up until now without any flickering, it's fine, it's just the LEDs that have failed.
There's a better choice of GU10 LEDs these days, and the good thing about them is that they take AC (transformer inside) so that that external transformer won't be necessary. Should be an easy job for an electrician to replace the fittings depending on access.

martinsurrey

that is a 60 watt equivalent transformer (60VA)

you've got 80 watts of LED on it.

4.9amps at 12v its 60VA

MX5huggy

martinsurrey wrote: »

that is a 60 watt equivalent transformer (60VA)

you've got 80 watts of LED on it.

4.9amps at 12v its 60VA

No there is a transformer for every lamp.

MX5huggy

So it's a fault with the lamp we think. Not the installation?

I don't really want to change them, the light they give is good and new fittings would be more money I am using LED save money.

martinsurrey

MX5huggy wrote: »

So it's a fault with the lamp we think. Not the installation?

I don't really want to change them, the light they give is good and new fittings would be more money I am using LED save money.

not yet, while the transformer may not be overloaded, it might not be compatible with LED lights.

if the transformer is of an older type, they don't work well with LEDS, and I cant find anything on that transformer...

http://www.ledconnection.co.uk/blog/category/leds-and-issues-with-transformers/

Bluetobits

For what its worth...
The cracking indicates a possible overheating issue which would certainly cause premature LED failure. LEDs generate a lot less heat than tungsten halogen, but are far less tolerant to withstanding the heat they create and sufficient airflow to dissipate this heat is more critical. This overheating could be as a result of one or more of the following

1. inadequate air circulation around the rear of the lamp[LIST=2]
2. smoke/fire hoods - these are usually necessary to restore the fire barrier properties of the ceiling which has been compromised by cutting the fitting mounting hole, rather than the function of protecting of the the surrounding area from the heat given off by tungsten halogen lamps. The lamps should not be fitted in any event should this be a risk.
3. thermal insulation , Rockwool, Kingspan etc.
4. enclosed and confined void space. (between narrow spaced or low height joists etc
5. enclosed fitting. Some TH fittings are fully enclosed. These negate the need for hoods, but in their nature are poor at dissipating heat.

[*]Defect within the lamp - [LIST=2]
[*]inadequate heat sink/thermal paste
[*]Incorrect or out of tolerance limiting resistor
[*]loose/poor internal connection
[*]mechanical damage resulting in any of the above
[/LIST]
[*]loose connection at lamp holder[LIST=2]
[*]Failed or weak wire to lamp holder connection
[*]Oxidisation on lamp pins
[*]Loss of temper in the sprung steel lamp holder connection
[/LIST]
[*]Faulty transformer. Nothing can be done about this.[LIST=2]
[*]Voltage drift
[/LIST]
[/LIST]
In my home I replaced around 30 MR16 lamps with LED and have found that at least 7 have failed within 2 years. Most of the failed ones are running from the original wire-wound transformer so I suspect they may be suffering over-voltage. None of the blown lamps showed physical damage, but all are well ventilated, some are branded, others not.
I hope this helps.

freshfruitbandit

I had MR16 halogens in my kitchen and when i found an LED company who knew what they were talking about they told me to change the fitting to GU10's. MR16 LED's need a transformer fitting for each spot and not all transformers work with all LED's. If you want them dimmable it's more complicated.

Never had a problem with any GU10 LED's i've got yet.

stator

It looks like a heat issue.
What is the clearing around the back of the lamp like?

almillar

not yet, while the transformer may not be overloaded, it might not be compatible with LED lights.
if the transformer is of an older type, they don't work well with LEDS, and I cant find anything on that transformer...

mx5huggy has confirmed there's a transformer for each lamp, so they're certainly not overloaded.
If they're all the same transformer, I'm under the impression that they've been running fine for years, and have only just started flickering. That would rule out the transformer being incompatible (due to UNDERloading) as that should show up within the first few minutes.
The damage to the LEDs themselves points to overheating and/or damage inside - a 'defect of the lamp' as Bluetobits says - replace the lamp.