I concur with Amanda's statement regarding the resistor values, voltage, and 3 LEDs per string. A just charged battery will have higher voltage and the current will rise dramatically. I usually design for 18ma at 14.4V.
Simple line powered LED bulbs are a problem. For 120VAC, it could handle 50 white LEDs in series. 220VAC could handle 100 LEDs. The problems are, if one LED fails to an open state (common) the bulb is shot, and if one LED fails to a shorted state, the voltage rises on the other LEDs, raising the current, leading to more LED failures.
Line power into LEDs could often be better utilized. The 20ma at 120VAC is 2.4W, and 4.4W at 220V. A CFL gets my vote for better use of power and longer life than very long strings of LEDs.
LEDs can be line powered other ways, but it can get complicated. The losses get higher and there are more parts to fail. Personally, for grid powered LEDs, I would prefer to grid-charge a battery for the LEDs. It's easier! G- [ Parent ]
Ok, ok, I got it. I overrun the LEDs a little. Next time i'll be more cautious. They were cheap anyway :-)
I got the point that line powered LEDs are not such a great idea. But what about the commercial bulbs? How are the made? I never opened a 220V one so I don't know what they use in terms of electronics. There has to be some better way of using line powered Led's as the LEDs business over here starts to grow dramatically.
I see building lighted with leds, I see commercial signs illuminated with LEDs too...
Here's my LED supplier. The page is in english too so it should be easy to get my point. http://www.zexstar.com/english/index.php?cat=26#[ Parent ]
The saddest part is the owner bought it to run it from a 12V inverter. G- [ Parent ]
I'll head for the fluorescent department now. No more fancy 220V LED bulbs anymore. In fact, I did made some fluorescent inverter bulbs for 6 and 12V but they were a little power-hungry for my taste. The consumption depends on the light output. It's all about a pair of resistors. A 12V/0.5A bulb I made will give enough light to stop you from bumping into things but if you really want light, 0.8-1.0 Amp/h is the way to go. This also comes with heatsinking so bye bye economy.
Yes, it's sad what that owner did. I imagine that bulb wasn't cheap. I feel sorry for him. [ Parent ]
Vawtman, I never saw those bulbs. I would not have much confidence in the warranty unless the brand name is old and common. I was pleased with the factory LED strings I looked at. Makes me wonder why... they include extra LED replacement bulbs? LOL
G-[ Parent ]
I couldn't get that link to work. Check them out at the link below, 50 , 5 led bulbs for $70.oo for the c-9's. How do these compare to the ones you found?
http://www.creativedisplays.com/siteresources/modules/webstore/scripts/prodList.asp?idCategory=37
Gordy[ Parent ]
So one day i thought maybe they made c9s led bulbs and found them.Seems lots of companies(sights getting in this).Maybe the price will come down has a result.
Thanks for helping [ Parent ]
The only commercial LED sign I ever saw up close must have a supply for each LED. "Each LED" was a cluster of 3 LEDs, red, yellow, and blue. I have a closeup photo, somewhere. It is in New York City in the NBC building. This photo is not so great, but it's all I found on the internet. http://www.nbcnewmedia.com/gallery/nbcExperience/globe.jpg G-[ Parent ]
From an energy perspective it still makes sense to use CFL over LEDs. The lighting of buildings with LEDs has a high gadget-factor, but is not the best thing if you want to minimize power consumption.[ Parent ]
This is true most of the time except when just a small amount of light will do. The smallest CFLs are about 3 watts and not all of them are useful. So if low light or highly concentrated light is needed LEDs can best CFLs. John..[ Parent ]
