Lights for Shed - These are Very Good

**BobL** · 31st December 2016, 12:03 PM

There's some interesting info on LED running temperatures, fitting LEDs and associated longevity of LED lighting on the web.

Some comparison temperatures under normal operation.
In fluorescent fittings the tube ends run from ~70 to 120ºC while the ballast should be no more than 60ºC.
Fluoro fubes should be replace when the tube end temps discolour or reach 130º - how many of us even know do that?
CF globe circuits operate at ~ 105ºC
Depending on the their wattage and to a lesser extent on their fitting Halogens and incandescents typical operate from ~125 - 300+ ºC

On this site LEDBenchmark - Unbiased LED lighting reviews., the performance characteristics of a very wide range of LEDs is tested and listed
Typical operating temps for higher wattage LEDs are around 80ºC, with the Osram (non-dimable) 10.5W said to operate at 92ºC which was the second hottest LED on the market at the time of these tests. The dimable version of the Osram is slightly derated, most likely so it runs cooler hence allowing the circuitry to last a bit longer

With lighting devices like CFs, Fluoros and LEDs, problems in the associated circuitry cause by excessive temperatures is a major contributor to failure and problems.
The problem is exacerbated when this circuitry is very close to the heat source i.e. the light itself..
Initially CF looked like the ducks nuts in lighting but then repeat failures of the circuitry, which usually lead to failure of the tubes, meant that very few of them reached their rated longevity. This is because these circuits are close to the heat source operating at too high a temperature, so while the tube itself may last, the circuit components don't.
The cheaper the CF the cheaper and less temperature tolerant the circuit components usually used, which lead to the higher than expected failure rates.

While LEDs run a bit cooler the same is expected to happen to LED lighting especially as lamp output is expected to increase further in the near future.
It's only because LEDs haven't been around for long enough we have yet to really see this effect.
To save money, cheap LEDs use even less temperature intolerant circuit components, so they will have a higher failure rate.
Compact LED lighting that runs direct off mains voltage, rather than via a 12V transformer, is also liable to have a higher failure rate because the rectification circuitry is right up near the LED which is where the higher temps are being generated. When things go wrong the readily available 240V is also likely to cause further problems, especially in an encapsulated downlight fitting. Hanging the LED from the ceiling on the end of a cord will be a better arrangement And although it's more inconvenient, running 12V lines for LEDs still has merit.

This temperature effect is very significant, hence purchasing cooler running LEDs, and fitting them so that they run as cool as possible is really worth considering, or the anticipated 20,000+ hours of operation will never be reached.

**Robson Valley** · 31st December 2016, 01:03 PM

I run a few 45W LED fixtures, about 45 device junctions (5 in each) in each lamp head. Brighter than 400W incandescent.
All of the circuitry at the screw-in lamp base is enclosed in a really prickly finned arrangement of heat sink fins.
I know for a fact that I can easily handle 50C and some 55C for shorter periods.
As I need to move and re-angle these lights for wood carving, I have never found them too hot for my hands.

CF are a liability in cold weather.

**BobL** · 31st December 2016, 01:22 PM

Originally Posted by Robson Valley

I run a few 45W LED fixtures, about 45 device junctions (5 in each) in each lamp head. Brighter than 400W incandescent.
All of the circuitry at the screw-in lamp base is enclosed in a really prickly finned arrangement of heat sink fins.
I know for a fact that I can easily handle 50C and some 55C for shorter periods.

LEDs with fins might be superior, OTOH this might give them an excuse to use less heat tolerant of heat components and so they are covering their behinds by fitting fins. If these are enclosed and not allowed access to cooler air there could be a problem down the track.

**Ubernoob** · 31st December 2016, 02:11 PM

Originally Posted by BobL

LEDs with fins might be superior, OTOH this might give them an excuse to use less heat tolerant of heat components and so they are covering their behinds by fitting fins. If these are enclosed and not allowed access to cooler air there could be a problem down the track.

We used to go through 20 incandescent globes a year at home then went to CFLs and we'd be replacing probably close to one a month. For us our voltage was too high. Voltage would peak at around 255Volts so after a couple of complaints the supply company did an adjustment at the local substation and we have bulbs that last for yonks.

We still have some sort of noise or something as you can see the LEDs and incandescent globes flicker a bit at full brightness and A LOT as they are dimmed, it also comes through cheaper stereos and a weird oscillating noise.
If you are very concerned about the effect of heat on LEDs the best bet would be to buy the LEDs and drivers individually and make your own 12V lighting system, loads of people have transformers(AC or DC) from old down lights that would run a multitude of LEDs.

**Robson Valley** · 31st December 2016, 05:27 PM

I can't get interested in hypothetical suggestions of future problems.
So far, they have performed as expected for daily operation for several years.
I plan to buy nothing but CREE 5X LED device lamps made in the United States.
Unfortunate if all you can find is offshore Pacific Rim goods.

In the usually weekly event of total power failure here in the village, I watch my Inverter measure the
increasing load from multiple LED lights and other essential electric motors.
Kind of a giggle, the inverter doesn't notice the regular domestic LED light loads at all!

Your mileage is sure to vary.

**BobL** · 31st December 2016, 05:38 PM

Originally Posted by Ubernoob

We used to go through 20 incandescent globes a year at home then went to CFLs and we'd be replacing probably close to one a month. For us our voltage was too high. Voltage would peak at around 255Volts so after a couple of complaints the supply company did an adjustment at the local substation and we have bulbs that last for yonks.

We still have some sort of noise or something as you can see the LEDs and incandescent globes flicker a bit at full brightness and A LOT as they are dimmed, it also comes through cheaper stereos and a weird oscillating noise.

The test site I refer to above also provides the % flicker for all the LEDs tested. The Osram 10.5W does really well on this test with less than 1% flicker whereas the Nichia 9W LED spot I have on my WW bench light has a 83% flicker! Folks wanting to set LED spots up over operating machinery might want to take that into account before buying.

**Ubernoob** · 31st December 2016, 06:30 PM

Originally Posted by BobL

The test site I refer to above also provides the % flicker for all the LEDs tested. The Osram 10.5W does really well on this test with less than 1% flicker whereas the Nichia 9W LED spot I have on my WW bench light has a 83% flicker! Folks wanting to set LED spots up over operating machinery might want to take that into account before buying.

I haven't read it as yet but in the house we have Lucci LEDlux which only output 700 lumens and consume 11Watts of power, we are not using certified dimmers so that may be part of the issue. There seems to be a decent capacitor as the lights are quite slow(for LEDs) to turn on and dim nicely when switched off. I haven't noticed any strobing when dimmed, the light may have the capacitor after the driver which would possibly explain the low lumen to watt ratio as it mean the LED sees constant current. I don't know a huge amount about how they work so I could be completely wrong but I am happy they don't strobe as it drives me nuts. A few new cars have day running lights and tail lights that strobe and I find them hard to look at.

**BobL** · 31st December 2016, 09:00 PM

Originally Posted by Ubernoob

I haven't read it as yet but in the house we have Lucci LEDlux which only output 700 lumens and consume 11Watts of power

They look alright! Low flicker% and relatively cool operation

LucciLux.jpg

**Robson Valley** · 3rd January 2017, 10:54 AM

LED are DC devices, if they strobe, the power supply might be an unbelievably crude square wave (just guessing)
I'm absolutely delighted with the American made, CREE LED lights. Upstairs and in my carving shop, 8W and 11W lights are adequate.

My power system inverter displays load. One single 60W incandescent is measurable. Up to 40W total LED does not appear in the load.
Not really relevant to the bigger issues of total power failure.
CFL are useless in the cold, they're frustrating crap. You people probably don't ever need to care. Tassie, maybe.

**BobL** · 3rd January 2017, 12:01 PM

Originally Posted by Robson Valley

LED are DC devices, if they strobe, the power supply might be an unbelievably crude square wave (just guessing) .

As has been mentioned before, if used it could also be the dimming circuit.

**Ubernoob** · 3rd January 2017, 09:36 PM

You can get a lot more light out of a LED if it's not fed DC, it just has to strobe quicker than the flicker fusion rate but I think the on time alters this a bit too.

It's sort of like a speaker, give it a square wave and it gets hot and turns to smoke at fairly low levels, switch it quickly and you can increase the output by quite a lot, with a LED it's also more efficient as the light isn't on for 100% of the time and you get less heat.

Lots of older(and some current) bike lights had massive strobing issues when dimmed, if you turned the handlebars quickly in the bush you'd see a few snapshots of the bush and your brain goes crazy trying to fill in the missing info.

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