Could my LED bulbs be overheating?
- Thread starter MisterBoy
- Start date
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So today I took the chandelier down and took all the shades off. Used contact cleaner and compressed air to remove any dust and muck and wired it up in my garage on the bench.
Left running full power on the dinner switch for 20min, not a single flicker.
Brought it back inside and connected it back up without moving any bulbs... Immediately the same issue, within seconds of turning on I have bulbs intermittently flickering but not in sync with each other.
So now what? Only differences seem to be:
Left running full power on the dinner switch for 20min, not a single flicker.
Brought it back inside and connected it back up without moving any bulbs... Immediately the same issue, within seconds of turning on I have bulbs intermittently flickering but not in sync with each other.
So now what? Only differences seem to be:
- In the garage it wasn't hanging just lying on the bench
- The garage is a different circuit... But nothing else on the house lighting circuit has any problems
The different lengths of cable between dimmer module and chandelier might be the problem.
The dimmer and LED drivers may be "upset" by the stray capacity between cores in that cable and between the cable and other cables.
The dimmer and LED drivers may be "upset" by the stray capacity between cores in that cable and between the cable and other cables.
change the switch as it's easy ?
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I've already changed it... In fact the one I took out thinking that was the problem is the one I used in my test rig in the garage.
I'm currently trying hardwiring the light ie no switch at all, in case as suggested in the previous post.
If that works I guess I'll just not have dimmable lighting! What I really don't get is why the lights don't flicker in sync though, I'd love some scientific theories!
Each lamps has an LED driver, these are switch mode.
Some switch mode drivers take a constant trickle of power from the mains. Others take the same power but in short bursts of power that is put into a store ( capacitor ), When the store in almost empty they take another burst of power. Taking these bursts of energy can cause a transient dip in the mains voltage on the circuit and this dip affects the operation of other switch mode drivers fed from the same source.
And presumably the dimmer has maximum power output as well as clever electronics... Could the flickering be something along the lines of two lights trying to take a short burst at the same time, and one doesn't get any?
I can confirm that operating without a switch all the problems go away.
Does this mean something in my wiring in this room is just incompatible with a dimmer (since it works in another room) or could a different switch overcome the problem?
Yes, and complicated by the probability that the dimmer creates a wave form that is not suited for drivers taking bursts of power. The dimmer may not be providing power when a driver wants power.
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It sounds electrical, but it could be a thermal issue in that light fitting. There will be no convection cooling as there is no air path for the cool air to get in so those lamps probably won't last long anyway.
Can you purchase another lamp from a known good brand and see if that behaves the same?
Can you purchase another lamp from a known good brand and see if that behaves the same?
Misterboy
My reading is that you have
So as you say, an untested area is the circuit.
At the chandelier, in the ceiling rose, do you have Neutral, Live and the Switched Live (ie one cable providing the power and one cable going to the switch)?.
I ask, as I would next try connecting the chandelier to the cable providing the power and ignore the cable going to the switch.
The chandelier will of course then be permanently on, but if it works flawlessly then this will suggest that there is an issue in the cable going to the switch.
SFK
My reading is that you have
- tested the chandelier
- tested the bulbs
- tested the dimmer
So as you say, an untested area is the circuit.
At the chandelier, in the ceiling rose, do you have Neutral, Live and the Switched Live (ie one cable providing the power and one cable going to the switch)?.
I ask, as I would next try connecting the chandelier to the cable providing the power and ignore the cable going to the switch.
The chandelier will of course then be permanently on, but if it works flawlessly then this will suggest that there is an issue in the cable going to the switch.
SFK
I've already replaced all 5 bulbs once with a different brand, and had 3 of the new ones replaced like-for-like. There might be thermal issues as well, but considering they start flickering immediately when turned on I don't think that can be the predominant cause. I have left the shades off when re-fitting it in the house too.
Finding exactly where the wires come and go is likely to be tricky as it is old wiring - the switch has red/black/green wires, the rose has blue/brown/green. An electrician fit a new light in another room and spent a while trying to find where the live was!
Maybe this is not quite what you're saying, but I could connect the chandelier directly to the wires at the switch? This would cut out some of the wiring at least. Beyond that I think we're pulling up carpets and floorboards.
Out of interest what could be wrong in the cables? Someone mentioned this above but the low power nature of LEDs surely means the wires are not going to be too thin. Are we talking capacitance effects or something like that, messing up the seemingly delicate interaction between dimmer and drivers?
I coud test that with my garage test-rig by adding a long extension lead I suppose?!
MisterBoy,
Okay, the fact that you have only one cable with "blue/brown/green" at the Ceiling and one cable with "red/black/green" suggests that there is some interesting wiring there - and that my method will not work. And I am not sure connecting it to the light switch cable will gain any knowledge - but I would try it anyway just for interest sake.
I cannot think of a wiring issue that would damage a 240V LED bulb in the manner you describe (overheating, flickering).
Okay, the fact that you have only one cable with "blue/brown/green" at the Ceiling and one cable with "red/black/green" suggests that there is some interesting wiring there - and that my method will not work. And I am not sure connecting it to the light switch cable will gain any knowledge - but I would try it anyway just for interest sake.
I cannot think of a wiring issue that would damage a 240V LED bulb in the manner you describe (overheating, flickering).
Is there another light operated by the same switch?
Good question, but no.
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