LED wattage

[tabbypurr]

almost entirely

NT

[tabbypurr]

some can, many can't in both cases

for smpsu ones yes, for CR psu ones what's wanted is a series capacitor.

NT

[tabbypurr]

you have to have an amazing depth of ignorance of electronics to think that.

[The Natural Philosopher]

Unless its a rubbish design of lamp

With most designs the LEDS are mounted on some kind if internal heat conductor that then is connected to the base whilst there is no direct connection to the envelope. So the base gets hotter than the envelope

In a general bulb even with a SMPSU about 5% of the input will go into PSU heating, about 10% of what's left (9.5%) will; go out as light and the rest (85.5% appx) will go out as LED heat.

[tabbypurr]

I don't think I've ever seen an LED PSU that is under 50% efficient.

NT

[Johnny B Good]

And that's also the case with CFLs (in this case, the compact fluorescent tube).

The cheaper LED lamps use a lossless (literally!) capacitor dropper usually with a low value resistor in series to limit inrush current. It's this resistor that introduces a modicum of loss into the ballast circuit

- maybe 5 or 10 percent of the energy dissipated by the LEDs themselves.

The more sophisticated switch mode ballast circuits probably account for less than 5% of the waste heat energy in an LED lamp so in either case, just as for the CFL, the majority of the waste heat comes from the LED string itself.

The good thing about LED lamps is their potential to achieve efficacies five times greater than the best CFLs ever could. Cree Lighting demonstrated a laboratory 303 LPW LED lamp some four years ago which, contrary to the head of Cree's marketing division's claim of "it takes 18 to 24 months to go from laboratory samples to marketable products" this process, according to Cree's own graphs, is more like a decade from lab to shop product.

By that reckoning, we might see such 300LPW LEDs by 2024 or shortly thereafter. However, more realistically, we might see 160LPW lamps in just another year or two which should produce a "drop in" LED replacement for the 150W incandescent GLS lamp capable of lasting the promised 15 to

25 kilohours in all but the most poorly ventilated luminaires.

[Scott]

Problem solved. I now have a full refund but no explanation.

[Scott]

What about Philips?

[Johnny B Good]

No idea. Perhaps Big Clive has stripped some down?

[Johnny B Good]

The important thing here, is that your money was refunded. I wouldn't be too concerned as to the 'why' of the refund; just be grateful that you

*got* a refund at all and move on.

As I've already mentioned, the main benefit of better efficiency LED GLS lamps is their ability to provide more light without overheating. Those cheap Poundland 6W 470/510 lumens lamps run cool enough to survive to their claimed hours lifetime rating so are useful in cases where its "40W incandescent equivalent" of lighting suffices.

However, I'd steer clear of the Golfball version since it lacks sufficient surface area to keep the LEDs cool enough to last more than a few weeks in a ceiling batten fitting. Likewise, steer clear of the 5W candle lamps and buy the 3W version instead (assuming the 220Lm suffices, eg bedroom wall light or a five or six lamp chandelier).

[Scott]

Agreed - case closed.

Thanks for your good advice. My requirement is somewhat unusual. My bathroom lights are E14 (smalll Edison screw) and I am trying to install cool white LEDs. Philips produce a warm white of 806 lumens. I contacted them and they say there are no plans to produce a cool white version.

I have therefore bought two B22 > E14 converters and two A60 Philips lamps. Provided these fit the globes (which are quite large) I am hoping this is a competent solution.