LED lamps

[Scott]

I have a couple of early LED lamps, with fins and very heavy. Are these as good as (or better than?) the present generation?

[Tim+]

I find plenty of heat-sinking reassuring in LEDs. Generally found in more expensive/better designed ones.

Tim

[Brian Gaff (Sofa]

Well if they are generating heat then that is wasted power. However, they are most likely electrically quiet, whereas the modern switch mode ones pulse the leds hard and can be a swine if you want to listen to any am radio! Brian

[Dave Plowman (News]

Unlikely to produce as much light. May be longer lived, though.

[polygonum_on_google]

As I understand, the lower the efficiency, the more heat dispersion will be required, so the heavier the lamp.

Quite likely not as good as current generation but might well not be worth changing them.

[Paul]

Looking at some numbers, I have an old bulb with fins that uses 15W. And a new bulb that uses 8.5W. Both produce the same amount of light.

I would use the wasteful 15W input 800LM LED bulb in the laundry room. The laundry room light does not remain on.

For the kitchen light, the 8.5W input 800LM bulb would pay for itself in one to three years or so. It depends on exact usage pattern. But compared to the 15W one, the payback on buying that newer bulb is worth it.

The old bulbs cost 7x what the new bulb cost, in terms of purchase price. But since I've already paid for the old one, that doesn't enter into the math.

All bulbs need attention to details. The LED bulbs should not be used inside a "globe". They would overheat. The old bulb in my example, the 15W one, says on the side of it "for operation upright, only". So not only does it have fins, it also has instructions on correct orientation. Inverting the bulb makes it run hotter.

Paul

[Andy Burns]

I have three Philips 806 lm 8W LEDs in the kitchen, they were saying

75mA at 230V, one of them "went" the other week, so I picked-up a couple of replacements, still Philips 806 lm 8W, but now saying 70mA so I guess Johnny B Good is going to be waiting a long time for his 240 lm/W LEDs to hit the shelves ...

[Andy Burns]

But that 75mA (and the newer 70mA) are clearly bollox, maybe someone printed the current for 110V lamps on the 230V lamps?

[The Natural Philosopher]

Clearly bollox? depends on what '8W' means,and how much of that current is in phase with the voltage.

8W = 16VA is not unknown if a capacitor dropper is in play.

[Andy Burns]

I thought they had to meet a decent power factor these days?

[The Natural Philosopher]

Well there is so much inductive load on the grid a little capacitance is always handy :-)

I dunno what the Law says ... and anyway its worse than that because of the proliferation of SMPS, most of which only draw power at voltage peaks.

[Paul]

Hot off the Kill-O-Watt

Old finned LED 60W dimmable 100W nondim 40W nondim

VA 19.4 11.1 21.1 8.4 W 16.5 8.8 12.5 5.0 PF 0.85 0.80 0.58 0.60

For some reason, the non-dimmable have worse PF.

The three on the right, are Philips purchased in the last month.

Paul

[Chris Green]

Presumably that's 100w equivalent, etc. When are we going to get back to simply giving the actual power consumption as the basic parameter, or possibly the light output?

[Peter Johnson]

I find leds acquired in the last couple of years to be to be considerably more reliable (none have failed) and brighter at lower wattage than their predecessors.

[PeterC]

Perhaps when 25,000h life isn't claimed to be 25 years when it's <3 years. On some packaging it's quite a search to find the wattage; also, why does the blurb claim 'high power' when I'm looking for lowest power for the required output?

[Paul]

The rating system, the "class" of bulb, is to make it easier for shoppers to "replace by application". The bulb in the refrigerator for example, we only need 25W for that one, so none of the above would be suitable in the fridge. Knowing that it uses 3W real power, wouldn't be as useful info.

The Philips I just bought, work down to -20C. Which means those particular ones might be OK in the fridge, as long as nothing condenses in the base. Maybe that's a good reason to have potting compound in the base.

And the color temperature and CRI, tell you what the light will look like. The three on the right above are

2700K 90CRI, which means roughly "almost the same as an incandescent". A warm-ish light, suitable for reading. The 5000K 85CRI bulbs I bought, the floods, those are dreadful, and I can't use those for anything. And I don't really understand what goes on with those, as the light is "white", but it's also "bleh" and indescribable in any meaningful way. They don't look bluish, as the 5000K would hint, there's no sign of blue the way some bulbs at that color temperature look. But the light is just awful and you just want to turn it off. It's "poke in the eye" awful. I'd rather light the room with a magnesium flare.

Paul

[alan_m]

I find the exact opposite. Those horrible 2700k orange/yellow monstrosities are far inferior to the cool white/daylight bulbs for reading (and for any other lighting)

Some of us can and find them much better than traditional bulb (colour temperature) equivalents.

[alan_m]

In my experience with the early type it was often the electronics in the base of the bulb that failed, probably because it got too hot in traditional light fittings - especially in downlighters with a limited free air flow and very little facility for heat sinking.

With more efficient LEDs and with the use of LED arrays dropping 70+V rather than single LEDs the electronic components are less stressed and hence more reliable.

As I'm going through my house re-decorating each room I'm replacing old light fittings with LED panel type (fancy "designer" type rather than utilitarian). These all have fairly large metal back plates to which a LED strip and the driver are attached giving a more than adequate heatsink.

[Scott]

My fridge needs the light to be permanently on when running below a certain ambient temperature to force the compressor to keep working. There is a winter switch for this purpose. I assume an LED light would not produce enough heat for this to work. Is this an unusual arrangement.

[Andrew]

My Liebherr fridge has this. It has an Invensys electro-mechanical thermostat. Maybe modern fridges with a 'chip' and circuit board do it more intelligently.