As someone said here the other day, what does a lumin look like and how accurate are the human eyes in judging actual brightness. It has a lot to do with the spectrum obviously, so we really do need some kind of rule of thumb way to tell with so many different sorts of lights around these days. Not much use to me, but interestingly, I am still affected by flicker and grainy lighting even thoug I can only see light and dark. Brian
I was looking on Ebay, so no BC adapters? That's odd as BC is more common.
only in the UK. Everybody else uses ES.
You do an awful lot of guessing. If only you'd stop stating it as fact.
Makers are all very happy to confuse. I've yet to see any low energy device which claims to have the same output as a ***W tungsten to actually be a direct replacement. They've obviously found the most inefficient tungsten to use as their baseline, if not plain lying.
I've found Megaman CFLs very good. I'm using both golf-balls and some of the spotlight R series. OK, you don't get instant light, but after 3 or 4 minutes you can't really tell the difference. Excellent for fittings that are on for 6 or more hours.
Strange, as BC is superior.
They use the same CREE LEDs inside. If you put on 50% more power, you get 50% more light. Therefore it's a fact. Anyway, I said "GUESSING".
Spotlights are rubbish, lights facing upwards are rubbish. Half the lumens are eaten by the wall or ceiling.
Unfortunately the LEDs flicker. The only non-flickery bulb I've seen is an incandescent, so I don't think energy saving bulbs are for you, unless you can find one with a decent power supply.
is that "eaten" in the same sense that calories eat away your clothes so they don't fit any more?
You're wrong about that too. That would only truly be the case on a 100% efficient device. If it's not that, the actual output could be lower - or higher - than you've guessed.
Can you preface all your posts with that?
Bullshit! You would only get 50% more light with an infinite heatsink. If held at ambient by magic and even then only approximately true.
The graph of relative luminous flux at constant temperature is also less than ideal - even in that case you are *WRONG*. see p6 below.
See the derating graphs for Cree LEDs light output as a function of junction temperature and current. This site has the graphs on p5/6.
But if you run them at maximum rating the junction ends up at around 60C in practice which loses about 10% of the luminous output and if it goes above 100C then losses are about 20%. Their actual working temperature depends a lot on airflow around the lamp - more is better.
Getting rid of the waste heat from LED lamps is difficult if you have to still match the physical shape of the classical filament bulb.
That would be a guess too? Or do you think all walls etc are the same colour? And all colours reflect light the same?
You really should stop buying things from the pound shop.
That's a good excuse.
Why would efficiency change when using the ame LED component?
Only when applicable.
WTF? Why infinite? The heatsink used is proportional to the number of LEDs they put in, so the temperature is the same.
The one I showed has an enormous heatsink. Don't get the GU10 spots, they get too hot to touch. They don't get dimmer when they warm up as you seem to think, but they do die fairly quickly. I'm really getting on the nerves of the supplier I bought some from 6 months ago, as I'm constantly getting replacements under warranty.
They certainly reflect nothing like 100%, that would be a mirror. And I've got both types here, so I have seen a comparison with my own eyes. Same bulb (the LED one with the hemisphere output) placed in a fitting with the bulbs facing up, then in a fitting with them facing down. The room is MUCH brighter when they're facing down.
I buy decent LED lights from Ebay. The difference is I've got better eyesight than you. I can see the flicker on almost every car LED light. They really should design them properly, distractions while driving are dangerous.
That's wrong there is no direct comparison between watts and lumens, otherwise my kettle would be really bright. And remmeber a 1mW laser can blind you for a while. So there is no real graph of watts verses lumens
It's not watts versus lumens. It's showing you what to expect from standard tungsten bulbs. It's relating the power consumption of a tungsten filament to the light it gives out.
One probl;em is that the human eye isn;t very good at recording brightness or colour as teh eye and the brain adapts. Trying looking at a bulb in daylaight.
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