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LED Lights
- Thread starter savage
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MontyPython
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Goobie and rsd,
please send me your email addresses to
[email protected]
and i will send you the 2 catalogues.
ps:
http://af.reuters.com/article/topNews/idAFJOE66R0NW20100728
MontyPython
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ROFLMAO
. . . . . . .
4 years ago, that was correct.
2 years ago the factories started to make dimmable LED's,
some with their own transformers for the 12V types,
some able to dim with standard wall dimmers.
the non-dimmables were cheaper than the dimmables.
currently non-dimmables are being phased out due to the demand for dimmable LED's.
Jola
Honorary Master
Yes, those 280 lumens SMD LED's turned out to be pretty good, and are about as bright as a 50w halogen light.
I originally only ordered 3 lights, but then ordered 5 more and now have 8 of these in my kitchen.
They are expensive, but I think that they are worth it.
The amount of misinformation regarding LED's amazes me. A 50W halogen produces more 800 lumen. Therefore, for a LED fixture to be a 50W equivalent, it needs to generate at least 700 lumen, surely?
And I can tell you now, such a device does not exist at the moment! I had a conversation with a local vendor, trying to convince me that their 10W LED, which produces 1200 lux at 1m from a 30deg beam, is equivalent to a 50W halogen producing 2600 Lux at 1m, from a 38deg beam. That's 260lumen versus 880 lumen!!!! More like a 20W replacement....
Earlier today I tried to get guaranteed fixture lumen output from a Chinese vendor on a 6W device, proclaimed to be a 50W replacement. The fixture output turned out to be 30% less than claimed.
Things to watch out for:
1 ) Lumen output claimed is for the LED's, usually cool white, which produces more. And then ignores the lens loss.
2) Wattage numbers mean very little... Lumen/w mean more, but only if it is at the temp(K) you need, and of the fixture, not LED.
3) Check the Lux rating, from which the lumen can be extracted, give the beam angle and distance: lumen = 2*pi*r^2*(1-cos(beamangle/2/57.3))*lux
or use this online calc: http://www.ledrise.com/shop_content.php?coID=19
4) High wattage fixtures need to dump more heat - if not, don't expect 50000hrs.
As said in a tv series long ago: "Be careful out there". There are a lot of snake-oil salesmen.
Ian
And I can tell you now, such a device does not exist at the moment! I had a conversation with a local vendor, trying to convince me that their 10W LED, which produces 1200 lux at 1m from a 30deg beam, is equivalent to a 50W halogen producing 2600 Lux at 1m, from a 38deg beam. That's 260lumen versus 880 lumen!!!! More like a 20W replacement....
Earlier today I tried to get guaranteed fixture lumen output from a Chinese vendor on a 6W device, proclaimed to be a 50W replacement. The fixture output turned out to be 30% less than claimed.
Things to watch out for:
1 ) Lumen output claimed is for the LED's, usually cool white, which produces more. And then ignores the lens loss.
2) Wattage numbers mean very little... Lumen/w mean more, but only if it is at the temp(K) you need, and of the fixture, not LED.
3) Check the Lux rating, from which the lumen can be extracted, give the beam angle and distance: lumen = 2*pi*r^2*(1-cos(beamangle/2/57.3))*lux
or use this online calc: http://www.ledrise.com/shop_content.php?coID=19
4) High wattage fixtures need to dump more heat - if not, don't expect 50000hrs.
As said in a tv series long ago: "Be careful out there". There are a lot of snake-oil salesmen.
Ian
MontyPython
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BRILLIANT!!!!!!!!!!!!!!!!!!!!!
Thats what i've been saying all along
280 lumen is NOT the same as 280 lux, and vice versa!!!
igeorge, you're my hero
Jola
Honorary Master
I don't know, I have 280 lumen SMD LED's (GU10's) installed, and visually they give the same light as a 50w halogen.
Maybe if you measure it, it would be slightly less, but it's not noticeable. So I'm happy with those, at about R180 each.
Canafrican
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Smd light stays on?
I bought the mr16 21 led cool white and they are good for very small room ssuch as toilet/bathroom
Now this is my problem - i bought a 48 led (3528) smd off ebay, got it today but when i connect it the light turns on but very dim, and when i switch the light on it is fine. In other words when i turn my light off the smd bulb is still on but very dim. Is everyones like this. I dont mind it staying on dim but it might shorten its life?
Thanks
I bought the mr16 21 led cool white and they are good for very small room ssuch as toilet/bathroom
Now this is my problem - i bought a 48 led (3528) smd off ebay, got it today but when i connect it the light turns on but very dim, and when i switch the light on it is fine. In other words when i turn my light off the smd bulb is still on but very dim. Is everyones like this. I dont mind it staying on dim but it might shorten its life?
Thanks
MontyPython
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Hello Abid,
it could be 2 things:
1: your LED is "on but very dim" is due to the LED getting current from somewhere else. probably some sort of short circuit, but not enough to trip the breaker. the live connection on the light fitting/socket is picking up live current after the switch from the live incoming connection and then its "leaking" throught earth or neutral, and the LED is sensitive enough to be able to give a very dim light output.
2: i take it these are downlights (MR16 or GU10).
take the lights out and rotate them 180 deg so that the pins connect to the other contact. again the LED's are so sensitive that if the "live" pin on the globe connects to the "neutral" contact in the socket the LED starts to light up, "but very dim".
my garage motor light does the same with one of my LED globes.
Professor Farnsworth
Well-Known Member
Be careful of having the power source far from the LED if they run off 12V - the low voltage and high power consumption imply high current flow and thus a greater voltage drop through the transmission line (voltage drop = I²R). For 20W at 12V, you need about 1.7A of current, so you lose (1.7)² times the resistance of the wire in voltage. This at drop in voltage would dim the LED and also heat up the transmission line.
Jola
Honorary Master
Anyone know what the correct import tax is on LED bulbs ?
SARS usually just charge VAT, but the last time it was 20% plus VAT, of course.
As if local manufacturers need protection, they don't exist !
Sent from the MyBroadband iPhone App
SARS usually just charge VAT, but the last time it was 20% plus VAT, of course.
As if local manufacturers need protection, they don't exist !
Sent from the MyBroadband iPhone App
bekdik
Honorary Master
LED bulbs not as eco-friendly as some might think
http://www.gizmag.com/led-bulbs-fou...aign=f4889c9454-UA-2235360-4&utm_medium=email
http://www.gizmag.com/led-bulbs-fou...aign=f4889c9454-UA-2235360-4&utm_medium=email
Interestingly, I've just ordered a batch of MR16 and GU10 6W WW LED's from my supplier in China...
If you use them to replace 50W halogens (not exactly a lumen for lumen swop, I know
), in a 8hr/day, 6 day/wk business scenario, they will pay for themselves in .48 years, or less than 6 months!!!
A 200% ROI - beat that anywhere!!!
A no brainer for any business!
If you use them to replace 50W halogens (not exactly a lumen for lumen swop, I know
), in a 8hr/day, 6 day/wk business scenario, they will pay for themselves in .48 years, or less than 6 months!!!A 200% ROI - beat that anywhere!!!
A no brainer for any business!