LED Christmas Lights, please educate me.

[ERD50]

I'd bet there are marketing considerations, too. While an LED that emits red light doesn't need to appear red, it's likely that Bill and Jane consumer expect to see red (and various other color) bulbs if that's the color light they want. So, the manufacturer puts colored glass or plastic covers over them.

Yes, I recall now seeing component LEDS that were red, and some had clear plastic bodies (but lit red), and some had red translucent bodies (which also lit red). Same LED inside, but I preferred the colored plastic as you could tell by looking what it was. I would want the same if I were decorating, it's a nice visual clue.

-ERD50

 

[ERD50]

2014 Update

I've now had three strings outdoors since 2011, so they are on their 4th season. They are protected somewhat, under an awning, but so far not a single LED has gone out, and no intermittent connections. I got 2 more the next year for the patio, two more the next year for some small trees on the patio, one string inside, and I bought 4 more to use next year (I wanted them all the same in the front, in case colors are different). These are all the warm-white from Walgreens, ~ $5 for a 50 string light set. Zero failures so far. Looks like they will last much longer than the filament sets, so the slightly higher price is OK.

It's been nice not fiddling with burnt out bulbs and intermittent strings.

-ERD50

 

[GravitySucks]

I've now had three strings outdoors since 2011

-ERD50

You beat my Dad. He used to take the Christmas lights down 4th of July.

Sent from my Nexus 7 using Early Retirement Forum mobile app

 

[ERD50]

Originally Posted by ERD50 View Post
I've now had three strings outdoors since 2011

You beat my Dad. He used to take the Christmas lights down 4th of July.

Sent from my Nexus 7 using Early Retirement Forum mobile app

good catch!

But for the record, they come down in January (each year - gotta be careful with those words)!

-ERD50

 

[Sunset]

What attracts me to them is the electricity savings.
I don't have a set, but I'm just being lazy as I put up the old set, so I have not bought LED replacements.
I figure we use $10 extra per month for Christmas lights, so with easily 1/5 the cost, the LED's should save us $8/mo paying for themselves in 1 to 2 seasons.

 

[Payin-the-Toll]

Had same experience as Rustic23. We put out 3 wreaths every year--bought LED's last year and restrung the wreaths. This year one strand was 1/2 burned out--replaced it. Actually, I like the color of LED lights--to me they seem more vibrant. Bought all red LEDs to do the tree and came up 100 lights short (we put 400-500 lights on the tree). Went to 7 stores and couldn't find any red LEDs, they were all sold out. Plenty of the old style bulbs though--I figured they would be obsolete by now and was surprised.

Saw an article on the net or news, and family put up 25,000 LED lights outside--and claimed it only cost $15 in electricity for the whole season---I call B.S.

 

[ERD50]

...

Saw an article on the net or news, and family put up 25,000 LED lights outside--and claimed it only cost $15 in electricity for the whole season---I call B.S.

Actually, depending on the variables (how many days is a 'season'?, how many hours a day? how much do they pay for electricity?), it could be ball-parkish right.

25,000 LEDs would be 500 strings of 50 each. My 50 string LEDs are using ~ 3.5 watts. 500 * 3.5W = 1750 watts total (1.75 kW). At the national average of ~ $0.11 per kWh, that's $0.19 per hour.

So $15 would pay for 78 hours of lighting. 13 days @ 6 hours per day would do it. 19 days @ 4 hours/day, etc.

They may pay less per kWh, but even so, not so far off to call 'BS' I'd say. And if they have 'blinkers', those are off part of the time, and no in-rush current with LEDs.

What attracts me to them is the electricity savings.
I don't have a set, but I'm just being lazy as I put up the old set, so I have not bought LED replacements.
I figure we use $10 extra per month for Christmas lights, so with easily 1/5 the cost, the LED's should save us $8/mo paying for themselves in 1 to 2 seasons.

I'd like to see your math. Or are you comparing to the really old-style 'night light' sized bulbs that are 6 watts each? I'm assuming people compare the LEDs to the mini-lights?

For me, the small electricity savings is a plus, but the (hoped for, and so far delivered) reliability is the key. Too much time spent replacing bulbs, trying to get strings to work, and then throwing several sets out each year, even after my attempts at repair (and I strip down the 100 light strings to make a 50 string with the half that does light).

By my calcs and estimates, with $0.11 kWh, 5 weeks at 8 hours per day, it would take about 20 strings to save $8.00. I'm paying ~ $5 for LED strings, I haven't price checked, but I'd guess the mini-light filament style are $2? The $60 delta would take a long time to pay back in electricity savings. But I think I'll see payback in durability. Less fiddling is something I'd pay for, replacing those little bulbs is tedious.

-ERD50

 

[ERD50]

2015 Update

I've now had three strings outdoors since 2011, so they are on their 4th season. They are protected somewhat, under an awning, but so far not a single LED has gone out, and no intermittent connections. I got 2 more the next year for the patio, two more the next year for some small trees on the patio, one string inside, and I bought 4 more to use next year (I wanted them all the same in the front, in case colors are different). These are all the warm-white from Walgreens, ~ $5 for a 50 string light set. Zero failures so far. Looks like they will last much longer than the filament sets, so the slightly higher price is OK.

It's been nice not fiddling with burnt out bulbs and intermittent strings.

-ERD50

So another year, and still not a single LED has gone out. Nothing intermittent, no problems at all (first LED strings were put up in 2011). So I've been very happy with them. So much better than fighting intermittent old filament-bulb strings, and replacing the bad bulbs so they don't cause the others to go out sooner, and trying to track down the bad bulb in a string (I usually give up on those).

I had enough bad incandescent strings to throw out last year, that I bought more LEDS so we could also do the Christmas tree inside in LEDs (that took 6 of the 50 bulb strings).

I've been trying to stick to the same brand to match the warm-white color as best I can. Been buying them at Walgreens, ~ $5 for a 50 bulb string. This year, Walgreen's changed the packaging, but I had brought an old box with me and the SKU was the same. But this years warm-white seemed a bit whiter than my previous strings. Not by a lot though, but noticeable side-by-side. Now I'm not sure if it is just year-year variation, or if the old plastic has turned a bit yellow, making them appear 'warmer'?

DW and I also thought the tree would look nicer if those 'warm-white' LEDs were 'warmer' yet. I did some research, and experimented and found a coating of thinned "Terra Cotta" colored paint (her hobby acrylics) matched perfectly to an incandescent (so why don't they tint the plastic?). I'll experiment some more after we take the tree down, but if I can thin the paint, and just dip each bulb in and set the string aside to dry, it shouldn't be that much effort.

-ERD50

 

[samclem]

So another year, and still not a single LED has gone out. Nothing intermittent, no problems at all (first LED strings were put up in 2011). So I've been very happy with them.

Thanks for the update. I'm ready to take the plunge.

I'll experiment some more after we take the tree down, but if I can thin the paint, and just dip each bulb in and set the string aside to dry, it shouldn't be that much effort.

It is at least possible, in theory, that the absorption of light by the pigment could increase the temp of the LED, reducing its life. Anyway, let us know if tinting works. Incandescents have the whole spectrum of light (the whole lack body radiation curve). I think LEDs work by simultaneously emitting three discrete colors. I think the tint will still work the same way as it does in incandescent bulbs, but maybe I'm overlooking something.

 

[ERD50]

Thanks for the update. I'm ready to take the plunge.

It is at least possible, in theory, that the absorption of light by the pigment could increase the temp of the LED, reducing its life. Anyway, let us know if tinting works. Incandescents have the whole spectrum of light (the whole lack body radiation curve). I think LEDs work by simultaneously emitting three discrete colors. I think the tint will still work the same way as it does in incandescent bulbs, but maybe I'm overlooking something.

No real heat build up on these. Each 'bulb' (I kind of hate using that term with LEDS, they aren't a glass 'bulb', but it's understood) is very low power ( ~ 3.5 W for the string of 50, so ~ .07 watts) and they are spaced ~ 3~4 inches apart. Very different from a 110V 13 W 'bulb' in a standard light bulb size - those get hot due to the LEDs being so close together, plus the switching circuit. And the paint isn't blocking much of the light anyhow, just a little tint.

Actually, the common LEDS like this are actually UV with a phosphor that glows white. Now if you see the ones that allow you to balance the color, those are RGB (though they may be totally separate packages, just combos of each color). But I think the tinting would work in either case, but maybe a little differently since the phosphor is more broad-band white, and the RGB LEDs are three spikes that add to white. But probably close?

Which brings up another techy question I've been pondering: One reason they use the switching power supplies in the lamp-bulb replacements is to prevent flickering (also for efficiency - a simple resistor would waste energy and create more heat). The switchers store energy in caps while the AC varies, and the switcher delivers it at a high frequency so we don't see those cycles.

These cheap Christmas LED strings are low power, so they just use a resistor and a series string of LEDs to match the 110V line. I think my 50 LED sets light 25 on the + cycle, and 25 on the minus cycle. The LEDs don't come on until the line reaches 25 x ~ 3V, so only on from when the wave reaches 75 V up to the ~ 170V peak and back down to 75 V as it goes back to zero and then repeats on the negative swing for the other 25. So each LED is only on ~ 1/6th of the time. So these things really strobe, but you only see it if there is relative motion. That strobing would be unacceptable for task lighting.

So the question - aren't there phosphors with a persistence (after-glow), like old CRT TVs and oscilloscopes, that would smooth the flickering? The same would apply to old tube fluorescent lights, but I guess they drive those with high freq now too. And I guess no one really cares about a little strobing for Christmas lights?

-ERD50

 

[samclem]

These cheap Christmas LED strings are low power, so they just use a resistor and a series string of LEDs to match the 110V line. I think my 50 LED sets light 25 on the + cycle, and 25 on the minus cycle. The LEDs don't come on until the line reaches 25 x ~ 3V, so only on from when the wave reaches 75 V up to the ~ 170V peak and back down to 75 V as it goes back to zero and then repeats on the negative swing for the other 25. So each LED is only on ~ 1/6th of the time. So these things really strobe, but you only see it if there is relative motion. That strobing would be unacceptable for task lighting.

Thanks for the explanation, and the info about the phosphor UV-->visible light coating (like florescent bulbs have). If they do stop glowing very quickly, I'd imagine it would be apparent in regular fast shutter speed photographs of the bulbs (1/500 second). Sometimes every other bulb would be lit, sometimes none, etc.

 

[6miths]

I must have about 30 strings up now. Two types. The main one is alternate red and green which glows steadily. Red and green together alone are hard to come buy and tend to sell out fast around here. The Chinese seem to like Easter colours. I wonder if green is somehow taboo... I have had them up for about 4 years and they are a dream compared to the old 7 watt bulbs. I leave the two runs up on the high eaves all year - sorry! They are southern exposed without shade and they have not faded at all. The 7-watt incandescent would fade dramatically after one summer. I have had two strands that have had half of the strand go out - they come down off linear runs and go on the bushes. I also have a second type that is red transitioning to green running up the trunk and limbs of one tree. They shimmer a bit as they change colours. All in all I am very happy with them all in terms of appearance, ease of handling and durability.

 

[RunningBum]

I started with LEDs about 3 years ago, buying a few more strings each year until now I when I no longer have to use any old incandescent strings. The rough math I did, which I'm not going to try to recreate, was that a string of lights shining (EDIT: correction on usage on math, and thus my conclusion on payback) 7 hours/night for ~40 nights saves about $.50 in energy per string for me, so the payback does take awhile. The lights are also a lot nicer looking, and a whole lot more reliable. No more yearly search for the loose bulb cutting the string out with my old strings, no fading of the color, and no going down the line replacing burnt out bulbs (so far). For some reason I still have a few old strings among my Christmas stuff, but I'm going to toss them this year.

 

[ERD50]

The rough math I did, which I'm not going to try to recreate, was that a string of lights shining 6 hours/night for 30 nights saves about $5 in energy per string for me, so the payback is quick. ...

I'd have to see that math. See my post # 32.

If you are comparing LEDS to the the big 7 or 4 watt bulbs (350 and 200 watts per 50 string), then you might see that kind of savings. But a more apples-apples comparison is the miniature incandescents, and the savings is small (17 W versus 3.5 W for LED), because those don't use much to begin with. A ~ $0.34 delta for a 180 hour season per string.

-ERD50

 

[RunningBum]

I'd have to see that math. See my post # 32.

If you are comparing LEDS to the the big 7 or 4 watt bulbs (350 and 200 watts per 50 string), then you might see that kind of savings. But a more apples-apples comparison is the miniature incandescents, and the savings is small (17 W versus 3.5 W for LED), because those don't use much to begin with. A ~ $0.34 delta for a 180 hour season per string.

-ERD50

I run my lights more hours and more days but it looks like I was off by a factor of 10. (almost) 40 days * 7 hours/day at my $.102 kwh = $.10 string. I didn't have my old string wattage so I used 6x LED which would be .$50/string, .$.40/string if it's only 5x. I think I only moved the decimal point over 2 spots converting the kwh rate to watt hours, when of course it should be 3. Not nearly the savings, but then again it's good to know I'm spending just over a buck total for energy for all my Christmas lights, and I still like LEDs a lot better for the other reasons.

 

[ERD50]

Thanks for the explanation, and the info about the phosphor UV-->visible light coating (like florescent bulbs have). If they do stop glowing very quickly, I'd imagine it would be apparent in regular fast shutter speed photographs of the bulbs (1/500 second). Sometimes every other bulb would be lit, sometimes none, etc.

Under the category of 'geeky fun', I managed to verify this w/o any equipment at all.

I took a loose LED string I had, and in a darkened room, held the last LED in the string in my hand, and whipped it back and forth quickly in an arc ( ~ 9 inches wide?). It was easy to see a streak of light, broken by the off times. Like a dashed line, maybe 3-4 on cycles shown. A little hard to make out, but it did look like the off time was longer than the on time, as expected (off for half the cycle, plus the time it takes to reach the threshold of LED turn on).

I then took an LED from the beginning, held them together and repeated it. I expected to see the on/off periods alternate. But they didn't!

More experimenting with a diode at the plug side, and it turned out that they didn't bother to alternate the polarity of the two 25 LED halves (the diode would turn the entire string on/off, rather than a half string at a time). At these low power levels, it doesn't really make any significant difference in terms of power balance. I just figured they'd be set up that way as part of the production process.

DW was not impressed.

On these strings I've bought the past few years (the Walgreens warm-white), I dont see any resistor in the line. Some others I had had a little module. I tested an individual LED, and it does not seem to have a built in resistor (I can't be certain, but the 170 V peak / 25 is 6.8 V and these things get very bright by ~ 3.7 V, and drew ~ 64mA. That's ~ 1/4W and I'd be afraid of blowing them with any more). Can't find any resistor though. Yes, I'l do some measuring from plugs to socket... later.

-ERD50

 

[samclem]

I was in Home Depot the other day and saw two types of LED replacement "bulbs" for the ubiquitous 48" T8 florescent bulb. One type was a direct replacement (so the power continues to go through the ballast in the fixture) and the other type required slight re-wiring of the fixtures so that the bulb gets straight 110VAC. The second type is about twice as expensive, but has the advantages of higher efficiency (lumens/watt) and higher reliability/longevity in use (no possible failure of the ballast.

I imagine that the second type is just a bunch of LEDs wired pretty much like one of these Christmas light strings, so that there are enough LEDs wired in series so that each bulb gets enough voltage to stay within its max limits.

Question: If these LEDs are actually drawing power only during about 1/2 of the total sine wave, is the electric meter going to bill me for the whole thing, or just for the portion used?

I have an old, useless florescent shop light (bad ballast that would cost more than a replacement fixture). I'm thinking of making a homebrew LED shoplight using a few strings of LED Christmas lights purchased on sale--just drill a bunch of holes in the reflector and put all the wires inside the housing that used to hold the ballast, wires, etc. Not UL approved. It's probably no cheaper than just getting an old-fashioned drop light with clamp and reflector and putting in a 10W LED bulb with an Edison base (the typical "60W replacement" bulb). Fun, fun!

 

[AllDone]

Wow! There are lots of those T8 replacements now. I've been watching them for several years because I have some soffit lights that need new ballasts, but now the LED bulbs are cheaper than new ballasts and put out more light. I hate replacing ballasts because I have yet to do it with out slicing a finger on the cheesy metal housings. I may just decide to slice my fingers up putting in LEDs instead.

Last time I looked, the T8 replacements were ~$100.

 

[samclem]

Last time I looked, the T8 replacements were ~$100.

Yep, they are quite a bit less now. IIRC, the "direct replacements" (no re-wiring to eliminate the ballast) are about $14 each, and the ones that require/allow elimination of the ballast cost about $30 each. Neither is significantly more efficient (lumens per watt) than the T8 florescent bulbs, and the LED units often put out fewer lumens than the T8 florescent bulbs, so the payback period would be very long. The reasons to change would be convenience (fewer bulb changes), reliability (esp if the ballast is eliminated) and near-instant full brightness regardless of temperature.
There's no "native" LED replacement lamp standard yet--they are now just emulating the legacy Edison-based incandescents and the 48" T12/T8 florescents. Maybe there will never be a new replaceable LED lamp that is unique to that technology--the old formats are well entrenched.

 

[ERD50]

...
I imagine that the second type is just a bunch of LEDs wired pretty much like one of these Christmas light strings, so that there are enough LEDs wired in series so that each bulb gets enough voltage to stay within its max limits. ...

I doubt it. The flicker would be pretty bad, and noticeable as you move under the light. Since people don't really work under the Christmas lights, and they are low brightness, the flicker isn't such a big deal. I'm pretty sure any indoor work light will have a switching supply built into it that switches at a high frequency.

Question: If these LEDs are actually drawing power only during about 1/2 of the total sine wave, is the electric meter going to bill me for the whole thing, or just for the portion used? ...

The watt meter averages out the draw. Watt meters don't account for power factor (which you could read with a Kill-a-Watt meter if you can plug it in), you are only charged for watts.

-ERD50

 

[MikeD]

In conclusion I've decided to install the incandescent C9 bulbs and I wasn't impressed with what Lowes, Home Depot, Rona sold. Maybe I'll check back online during boxing day or what you Americano's call "Black Friday". When is that by the way?

It's Thanksgiving's Day's Boxing Day!

Mike D.