LED Lighting & Energy Efficiency

[EVnut]

By the way, this guy's effort to convert his house to 100% LED is interesting:

12V LED Lighting

He did this a few years ago when off the shelf options were more limited. He improvised a lot of custom fixtures.

Don McLeish is a good friend of mine. I find your choice of words interesting, as I sure don't see much off the shelf stuff still today that can match anything like what Don has done. Yeah, there are some screw-in bulbs as have been shown here - but you just can't get enough light out of a retrofit. This stuff needs to change at the fixture level to work well today.

One of my main hobbies is LED lighting, and I've done all kinds of automobile retrofits, and a bit of home lighting as well. Here are some of my home projects:
Fixed lighting

 

[TEG]

There are much easier options now.

These are some around my house now.

 

[vfx]

...Bathroom @...
Fixed lighting

Electric and Hybrid?

http://www.teslamotorsclub.com/tesla-motors/396-ev-rags-needed.html?highlight=magazines+rags

 

[TEG]

GU10 Hallway lighting:

(10watts of LED seems as bright as 100watts of incandescent)

Kitchen undercabinet lights (1 watt LED array replaces 10 watt halogen)

 

[TEG]

Recessed ceiling "can lights" with standard E27 flood.
Replaced 75watt halogen with 7 watt Nichia lensed array screw in bulbs.

 

[EVnut]

Thanks for all the great pics! I'd be quite curious to see how these compare to some of the stuff I've done. The modern stuff still can't get around the physical limits (mostly of waste heat dissipation) of incandescent fixtures, unfortunately.

 

[ChargeIt!]

Electric and Hybrid?

See Electric and Hybrid?

 

[TEG]

None of those fixtures I showed get hot. If anything they are just barely warm. The overall light output per bulb is somewhat less than what you could get with a high power conventional bulb, so the answer is to just add a few more fixtures around and have a few more light sources. That beats trying to overdrive individual LEDs.

Here is an example of a screw in replacement bulb for the can lights that has a heat sink built into the bulb:
LEDwaves.com: PAR-20 Argos LED Light Bulb 9-Watt (Nichia 083BT LEDs)

 

[EVnut]

I have several that look very similar with all kinds of neat vanes and such. They get blistering hot when put into enclosed cans. This was the first generation of Cree units where the emittes were under-driven - and there is PLENTY of waste heat to deal with still. And on top of that the output was pretty sad. The stuff I've done has just blown away all the stuff I've ever purchased. I'm thrilled to hear about your great results though! I'll definitely have to revisit.

 

[EVnut]

Another indicator to track are watts used.

Quite true... and yet this depends on the efficiency of the emitters of course. A bulb that consumes 1W from last year won't be nearly as bright as one from this year. And the big thing to watch out for is the use of wattage as some sort of brightness scale. Ug. We have GOT to get away from using Wattage for this! And then there's the crazy thing that the marketers are doing with listing the power *rating* of the LEDs on the package. So a bulb or a flashlight will be using a "5W" LED, or a "3W" LED. As if this has *anything* to do with how bright the product us. This rating, of course, is only how much wattage the die can handle - has nothing to do with how much wattage is being supplied to the emitter.

In the end, all we *really* care about is how many lumens are coming out of the device (not how much the LED is rated for, but how much we actually get to use!

 

[TEG]

In the end, all we *really* care about is how many lumens are coming out of the device...

Well, yes, clearly you want max lumens, not max watts.
But your statement leaves off all the other things you want too like high CRI, good color temp, appropriate flood, etc.


That reminds me... Apparently some really cheapo LED home bulbs also use half wave rectifiers and can produce some 60hz flicker.

 

[EVnut]

Well, yes, clearly you want max lumens, not max watts.
But your statement leaves off all the other things you want too like high CRI, good color temp, appropriate flood, etc.

You're right, of course. I just had to get my rant in about Wattage ratings on bulbs. The other stuff is VERY important, and CRI is still one of the most difficult with "white" LEDs. But they're making great in-roads there too (though with a hit on efficiency).

That reminds me... Apparently some really cheapo LED home bulbs also use half wave rectifiers and can produce some 60hz flicker.

Oh yes! I have several of those from the early days. They're HORRIBLE. There are still some cars being made with LED tail lights that flicker as well. As they're powered from a DC source, I've having trouble figuring out how they made those things so awful.

* TEG... I've read back over my comments on this thread and some of them sound like I'm jumping on you or trying to show where you're wrong. Sorry about that - totally uninentional. Sometimes I just desperately want to add to a thread, and I end up not having enough time to make it sound right. Thanks for being civil even when sometimes it sounds like I'm NOT being friendly! Hidden way deep down there, I'm actually a pretty nice guy. :tongue:

 

[doug]

There are still some cars being made with LED tail lights that flicker as well. As they're powered from a DC source, I've having trouble figuring out how they made those things so awful.

Those lights are using pulse width modulation to adjust perceived brightness. For example parking lights may be 30% duty cycle, but when you step on the brake, the duty cycle may go to 100%. The modulation frequency should be fast enough that you don't really notice the flicker. However, if the lights move across your field of view, persistence of vision should let you see a tracked strobe effect.

 

[TEG]

* TEG... I've read back over my comments on this thread and some of them sound like I'm jumping on you or trying to show where you're wrong. Sorry about that - totally uninentional. Sometimes I just desperately want to add to a thread, and I end up not having enough time to make it sound right. Thanks for being civil even when sometimes it sounds like I'm NOT being friendly! Hidden way deep down there, I'm actually a pretty nice guy. :tongue:

From one warm-hearted curmudgeon to another: it's all good...

 

[EVnut]

Those lights are using pulse width modulation to adjust perceived brightness. For example parking lights may be 30% duty cycle, but when you step on the brake, the duty cycle may go to 100%. The modulation frequency should be fast enough that you don't really notice the flicker. However, if the lights move across your field of view, persistence of vision should let you see a tracked strobe effect.

Yeah, hmmm. Too bad I didn't stop for like 10 seconds and think about that before posting. There's just no excuse for that crap! We've been using PWM in flashlights for many years. The key- of course - is the proper frequency, as you say. Jeez. I just don't understand what these guys were thinking. Maybe their synapses fire slower than the rest of ours, and they don't notice the flicker?

We (we meaing EE's that I've worked with who are far smarter than I could ever hope to be) have seen that PWM sucks for emitter longevity. But I guess some folks still find it easier than simply current-regulating at the proper level. :shrug:

If you can't tell, I'm one of those guys who is REALLY sensitive to flicker. The old flouros were terrible. Crappy computer monitors, PWM LEDs... you name it, it drives me mad. When I'm behind one of these guys on the freeway, I'm like a moth to a flame. I can't keep my eyes off the stupid thing. I think that's how drunks respond to flashing lights. Hmmm.

 

[EVnut]

From one warm-hearted curmudgeon to another: it's all good...

Groovy! OK, back to being me.

 

[TEG]

I am hyper sensitive to flicker too.

All I can conclude is that China has been dumping a lot of low grade cheap products (including LED tail lights) that use overly simplistic circuit designs in an effort to win the high volume bounty that comes with having the lowest cost product.

As buyers become more discerning, the PWM circuits will get better and the prices will go up.

( here is a forum topic where some customers try to find alternate drivers with less flicker. )

 

[EVnut]

I am hyper sensitive to flicker too.

All I can conclude is that China has been dumping a lot of low grade cheap products (including LED tail lights) that use overly simplistic circuit designs in an effort to win the high volume bounty that comes with having the lowest cost product.

As buyers become more discerning, the PWM circuits will get better and the prices will go up.

You're right on the money, I'm sure. Trying to convince some folks that the best product is NOT the cheapest is often quite difficult.

here is a forum topic where some customers try to find alternate drivers with less flicker.

Oh... don't even get me started on dealextreme... not in a duscussion about how going for the lowest production cost gives us what we seem to want! (as an aside the dealextremem folks have made a buisiness out of directly ripping off a good friend's many flashlight designs - right down to the exact name and engraving!)

 

[vfx]

Also sensitive to flicker but even more particular about CRI.

Last Halloween I bought several Orange LED strings for use around the house. It's too orange of course but not by much. In many places the warm color is welcome.

Have two strings circling at the back of my plasma TV to to wash on the wood wall.

In the day you can barely see them on but if you notice them they look good. At night they are a wee bit too warm. Maybe I'll try cutting it like Darryl does by adding in some "white" LEDs.

I can post a picture if someone wants.

 

[EVnut]

Maybe I'll try cutting it like Darryl does by adding in some "white" LEDs.

Ah, the Darell way in reverse. Yes, warming up a bunch of "white" LEDs with some amber or red works really well. I wonder how well it would work the other way - trying to "cool" a warm frequency with the addition of some white or blue. I've never tried it. Eventually (this is my hope!) we'll have RGB emitters that will allow us to dial in just the perfect color temp for our needs or mood. We can already do this, but the wildly different forward Voltages of the different colors make the packaging way less than ideal!