LED lights for home use

[Tinfoilhatmann]

I am a bit of an expert with LEDs and some of them will glow for a time after being disconnected. Depending on how some of them are built, they have to convert from 110v AC to 12-24 volt DC and I suspect the power supply is storing a charge for some reason.

I was going to open up an LED importing business a few years back and had ordered hundreds of samples from China and did massive research. Long story short, LED technology for the home user is not where it needs to be to be viable. There are simply not enough lumens per watt. The higher the wattage LED, the more expensive it is and the more heat it will produce, thus lowering its lifespan. The higher wattage LEDs are very expensive as well and instead of lasting 100,000 hours they only have a 10 or 20,000 hour lifespan.

The tech does exist for higher lumen LEDs but it is still far too expensive for the home consumer to use.

Some of these LEDs were great, although pricey. At the available lumen levels, you need a 10-15 watt LED to replace a 60 watt incandescent to achieve comparable lumen levels. Also, any LED that is warm white as opposed to the cool white (bluish) will have 10-15% less output because of the coating used to make it warmer. Of the dozens of manufacturers that I looked into, some of the samples were utter crap. They were DOA or stopped working after a few dozen hours. Some of them sparked a shorted out... a wonderful fire hazard. Some of them were dim and bluish and others simply fell apart. I think the ratio of bad to good was 40/60. I'd ordered 200 10 watt floods for a customer and within 6 weeks half of them were dead and I had to give them their money back. I gave up after a while.

On the flip side, there is some spectacular high end LED stuff. We use them constantly in show business and they are ahead of the curve. Pricey, but worth it if you get them from the right manufacturer.

The LEDs used here are 36 watt RGB. Twelve 1 watt ,15 degree diodes in each primary color of red, green and blue for a total of 36 watts. All 3 mixed will make white with a total power use of 36 watts.



Here are the same LEDs using only blue at 12 watts.



LEDs have endless applications but the problem with LED/incandescent replacement is it hard to cram in enough LEDs to make it bright without burning them up prematurely on a tiny platform like a screw in 60 watt light bulb. It is coming , but not for a little while yet. Another thing to consider is that over 90% of all LEDs are made in China.

[Katie]

Tinfoilhatman, those pictures are amazing.  Thanks for sharing your expertise.  Very interesting stuff. 

So far I've had decent luck with the LED's I got at Sam's Club and Lowe's compared to what you describe.  All the LED's are still working that I put in when I first posted about it.  I'm not comparing them to regular lights, since I got them thinking about lighting ATOC.  In the kitchen, I got the 5.5 watt LED strip from Lowe's over the counter top and it really gives me good task lighting at the counter.  I can chop veggies on a cutting board easily.  I have three 1.1 watt LED bulbs in the overhead fixture.  It gives me enough light to do normal things in the kitchen, like get a glass of water, etc.  I could chop veggies with the overhead if I had to, but it wouldn't be very comfortable.

I did get one set of the candelabra type that I think have some problems.  I put in a new ceiling fan, then put in those lights and they seemed to flicker, so I took them out.  I'm still not sure if it's the wiring in the fan or the lights, so it's all turned off until I have time to check it out.

I don't know how long these will last, but for now they are working better than expected.  They are not too bluish.

Now if we could figure out how to make those lights keep glowing for a long time after they are unscrewed, we'd have technology that would make peak oil irrelevant 

   

[Tinfoilhatmann]

Another important thing to remember about drop in LEDs is most of them are NOT dimmable using conventional fixtures and dimmers. Most LEDs require precise voltage and if it drops too low it can cause them to fail prematurely.

[Chip Haynes]

Sounds like I'll have to check out those 5.5 watt LEDs at Lowe's!

Mostly, we're waiting for marketing to catch up with application. A year from now, we should see a much wider variety of LEDs for home use. Until then, we take what we can get.

[Zac]

Another important thing to remember about drop in LEDs is most of them are NOT dimmable using conventional fixtures and dimmers. Most LEDs require precise voltage and if it drops too low it can cause them to fail prematurely.

That's a limitation of the driver circuit that converts 120VAC to the voltage (~3.6V for blue/white LEDs, ~2.2V for green, ~1.8V for red) the LEDs use. 

A bare LED cannot be damaged by too low a voltage.  It will just be dim or not turn on at all.  LEDs are ideally driven by a circuit that maintains a constant current.  A white LED driven at less than the rated current will last longer than when it is driven at the full rated current.  This is often what is done with white LED backlights that need to be kept illuminated continuously

[Katie]

Sounds like I'll have to check out those 5.5 watt LEDs at Lowe's!

Mostly, we're waiting for marketing to catch up with application. A year from now, we should see a much wider variety of LEDs for home use. Until then, we take what we can get.

They have a few different ones.  The one I got was the UtiliTech 18" LED Strip Light.  Some of the others didn't seem to put out enough light.