LED Christmas lights - love 'em or hate 'em?

[Ed.Kloonk]

Yup, that's the Washington Post all right - owned by Jeff Bezos of Amazon!

Washinton Compost

[Red Squirrel]

Speaking of LED lights, is there any suitable replacement bulbs that are LED that fit in "mini light" incadescent sockets?  The ones that are in series where the bulb has a shunt so it closes circuit if it dies.   I have a tree with them built in and they are burning out, and if too many burn out the whole string goes as they are getting too much voltage.   I have yet to find suitable replacements, I tried different voltage ones but sooner or later the whole string just dies.   Also, can someone explain this one?  If I put a 12v rated bulb, it dies immediately, while the 3v one does not.  Why would the higher voltage one die when the lower voltage one does not?  Since I did not know the voltage originally I figured I would start with highest and work my way down but that did not quite work!

[james_s]

I've never seen retrofit bulbs sold, but there is nothing stopping you from installing ordinary LEDs and then add a suitable current limiting resistor or proper constant current power supply to each string, ready made LED mini lights usually just have a resistor in series.

How many bulbs are in each segment? 20 used to be common but now most are 35 or 50 using 3.5 and 2.5V bulbs respectively so the 6V bulbs required for the 20 light segments are somewhat difficult to find. Things are complicated by the fact that some bulbs use more current than others so you may replace a 3.5V bulb with another 3.5V bulb and find that it runs high or low, throwing off the voltage on the rest of the bulbs in the string. I usually wait until right after Christmas and then buy up a bunch of bulbs at steeply discounted prices and then in my vintage strings I'll replace all the bulbs in a segment if the spares I have don't perfectly match.

A light dimmer set at 80-90% will dramatically increase the lifespan of incandescent lights for only a modest penalty in apparent brightness.

[themadhippy]

A light dimmer set at 80-90% will dramatically increase the lifespan of incandescent lights for only a modest penalty in apparent brightness

A  diode is another way

[james_s]

A  diode is another way

I find that I can see the visible flicker when using a diode on incandescent though even at 60Hz, I'd imagine it must be much worse on 50Hz, and also it drops the power down enough to be noticeably dimmer.

It's also a curious fact that incandescent lifespan is reduced on DC vs AC, which will partially offset the gains of the lower voltage.

Either way a dimmer is nice in that you can customize the brightness at any point. I usually run my christmas lights a bit dimmer in the weeks leading up to the holiday and then turn them up higher during events when people are over.

[tom66]

Generally, I like them, but I find the multicoloured ones fairly tacky.  The warm white ones are pleasant;  not sure I like the cold or cool white ones at all. 

[25 CPS]

I'm curious, does anybody know what the utility companies position on LED lighting is?  I remember reading about a 1970s TV regulated power supply circuit that introduced a nonlinear current waveform that caused some issues in places where it was in common use at the same time of day so I was wondering if LED lighting, Christmas or otherwise, being a nonlinear load has been a problem or at least something that's noticeable from the electricity utility end?

[Red Squirrel]

I've never seen retrofit bulbs sold, but there is nothing stopping you from installing ordinary LEDs and then add a suitable current limiting resistor or proper constant current power supply to each string, ready made LED mini lights usually just have a resistor in series.

How many bulbs are in each segment? 20 used to be common but now most are 35 or 50 using 3.5 and 2.5V bulbs respectively so the 6V bulbs required for the 20 light segments are somewhat difficult to find. Things are complicated by the fact that some bulbs use more current than others so you may replace a 3.5V bulb with another 3.5V bulb and find that it runs high or low, throwing off the voltage on the rest of the bulbs in the string. I usually wait until right after Christmas and then buy up a bunch of bulbs at steeply discounted prices and then in my vintage strings I'll replace all the bulbs in a segment if the spares I have don't perfectly match.

A light dimmer set at 80-90% will dramatically increase the lifespan of incandescent lights for only a modest penalty in apparent brightness.

Hard to tell because of how they are built into the tree, my guess is like 25.   And yeah I would not be against altering the voltage, just can't seem to find actual replacement bulbs that are LED.  I think through hole LEDs would maybe work but those are not bright at all as they are only really meant for indicators.

Never thought of adding a dimmer I suppose that may be an option to make them last longer.   And yeah with a diode I would see the flicker.   I have some LED lights in there too just to add some colour and I run them off rectified mains so the flicker is not as bad.    Tempting to throw in a capacitor but I feel the lights may not like that as they are probably not designed to run at full duty cycle.

[andy2000]

... Also, can someone explain this one?  If I put a 12v rated bulb, it dies immediately, while the 3v one does not.  Why would the higher voltage one die when the lower voltage one does not?  Since I did not know the voltage originally I figured I would start with highest and work my way down but that did not quite work!

That's because with series string lights, the current draw of each bulb is critical.  If you put 12v 100 mA bulb in a set designed for 3v 200 mA bulbs, the 12v bulb will see roughly 24v and blow instantly.  It's actually worse than that because the other bulbs never receive enough current to light up, so their resistance is a lot lower than when they are operating, so the 12v bulb probably sees close to 120v.   Higher voltage bulbs are usually lower current so that the power for each bulb stays reasonable. 

I generally measure the current draw of the bulbs in my lights sets and write it on the plug.  I also sort my spare bulbs the same way.  The best place to get spare bulbs is from other light sets.  For longest life you need to replace bad bulbs immediately.  If more than a few blow, the other bulbs see excessive voltage and fail quickly. 

[themadhippy]

funny Ive never really noticed the flicker with incandescents

Never thought of adding a dimmer

Best to check your chosen dimmer will play nicely with the load,if theres not enough you can get  very noticeable flashing

[james_s]

funny Ive never really noticed the flicker with incandescents

Never thought of adding a dimmer

Best to check your chosen dimmer will play nicely with the load,if theres not enough you can get  very noticeable flashing

That's not likely to be a problem. Strings of incandescent mini lights draw a surprisingly large amount of power, seems like a 100 light string is around 60 watts though it's been a while since I've checked. A tree covered in lights can easily draw 150-300W.

[james_s]

Hard to tell because of how they are built into the tree, my guess is like 25.   And yeah I would not be against altering the voltage, just can't seem to find actual replacement bulbs that are LED.  I think through hole LEDs would maybe work but those are not bright at all as they are only really meant for indicators.

Never thought of adding a dimmer I suppose that may be an option to make them last longer.   And yeah with a diode I would see the flicker.   I have some LED lights in there too just to add some colour and I run them off rectified mains so the flicker is not as bad.    Tempting to throw in a capacitor but I feel the lights may not like that as they are probably not designed to run at full duty cycle.

Remove a bulb from a working section and see how many lamps go out. Shouldn't take too long to count, it will be either 20, 35 or 50 most likely. You could also remove one of the existing bulbs and run it up on a bench supply and see what voltage it takes to make them light normal brightness.

[themadhippy]

That's not likely to be a problem.Strings of incandescent mini lights draw a surprisingly large amount of power, seems like a 100 light string is around 60 watts though it's been a while since I've checked.

On this side of the pond  the old incandescent strings were a bit more modest,20 or  40 lamps,at around 1/2 watt each.

[james_s]

I think the lamps are pretty similar, the size of the strings varies though. In the last 30 years or so 35, 50 and 100 light strings are the most common. In the 70s 20 and 40 light strings were around too but even then you could get 100 light strings. 10 light strings also exist, those are mostly integrated into tree toppers, stars, angels and other assorted stuff has been popular over the years.

[coppercone2]

i like them on trees and such, if they are hung on a wall it looks cheesy. they remind me of the glow worms from pitch black when they are on a wall. If they are the ones that drape periodically(branches) it looks better, but just having a single string that droops down is not a good decoration. There also needs to be alot, when you just put a few, the only thing that comes to mind is a half assed Christmas decoration in tropical islands or something (usually string of lights and a few beer cans on the table). It reminds me of palm trees that are decorated when there is not enough lights, and for some reason I cannot stand the 'single string of lights wrapped around a palm tree with a half twist). Those lawn chair crappy hot weather chirstmas decorations are really bad. When I see it I think 'good lord corporate bean counters got to the decorations'.

I think the new LED lights look better, at least the color ones, if they are good quality. Especially the blue and purple etc. the non tinted ones (clear glass) in incandescent have their own appeal.

Now I am not saying it needs to look like a projected hologram, but it should NOT look like a radio tower warning illumination lights.

ghetto/bad decoration (getting creative with the storage cost huh?)
https://i.pinimg.com/originals/04/4b/c3/044bc37d9d7a06c840996be85e44afcb.jpg
I assumed its inspired by a anaconda attacking native americans in a teepee scifi original feature

good decoration
https://d.newsweek.com/en/full/1254175/gettyimages-1069216858.jpg?w=1600&h=900&q=88&f=d1e0173ca5dc955c09b9b704750745c7

[tom66]

I'm curious, does anybody know what the utility companies position on LED lighting is?  I remember reading about a 1970s TV regulated power supply circuit that introduced a nonlinear current waveform that caused some issues in places where it was in common use at the same time of day so I was wondering if LED lighting, Christmas or otherwise, being a nonlinear load has been a problem or at least something that's noticeable from the electricity utility end?

My guess is it has a negligible effect compared to things like motors in washing machines, which are often triac-chopped, or small switch mode power supplies (sub ~50W) which don't require PFC.

[james_s]

IIRC most of the decent quality LED bulbs have a reasonable power factor, I'll measure a few different bulbs next time I've got the stuff out. Christmas lights will be cheap and nasty of course but those are negligible, being used for only a few weeks out of the year and mostly in modest quantities.

[tom66]

Our LED bulbs run off AC transformers and the controller decides which pair to light by chopping the positive or negative.  I imagine that having a modest inductance in the circuit goes some way to reduce the effects on the power grid.

[madires]

So far I've seen LED fairy lights with some sort of controller powered only by a small SMPSU wall wart. Half the LEDs in the string are wired in parallel, and the other half anti-parallel. The controller generates a PWM and also switches the polarity to select which half of LEDs to light. Usually they have 8 modes.

[Cyberdragon]

We have all the way up to RGBW LED strings here, saw a tree lit with them at Micheals.

I prefer incandescant to LED, the warm white ones aren't that bad though (the unrectified ones are a bit nasty though).

I like the color of (multicolor) phosphor LEDs better than bare dies, but I haven't seen them outside of battery sets, where they are used so they all drop the same brightness as the batteries drain. I would love to get a hold of a set of vintage phosphor light string, while dim the color is very unique.

Another thing about LEDs is the current draw is low enough that they can be easily driven from audio output vacuum tubes. One of these days I want to try and build a lighting controller using tubes, it would probably probably only have a few functions and I'm limiting it to a three color string. Also decatrons are pretty much off the table since they need 350+V which is well above the about 160V of rectified NA mains. You might be able to get away with using them on european recified mains but they might be unstable.

[S. Petrukhin]

I find that I can see the visible flicker when using a diode on incandescent though even at 60Hz, I'd imagine it must be much worse on 50Hz, and also it drops the power down enough to be noticeably dimmer.

Can you see interference with another light source flashing slightly with a phase shift?

[S. Petrukhin]

I'm curious, does anybody know what the utility companies position on LED lighting is?  I remember reading about a 1970s TV regulated power supply circuit that introduced a nonlinear current waveform that caused some issues in places where it was in common use at the same time of day so I was wondering if LED lighting, Christmas or otherwise, being a nonlinear load has been a problem or at least something that's noticeable from the electricity utility end?

I think the led load is not so large that it is noticed by the power company. Although, in the modern power supply network there are so many pulse consumers that the sinusoid has long been bitten off by the tops.

[james_s]

So far I've seen LED fairy lights with some sort of controller powered only by a small SMPSU wall wart. Half the LEDs in the string are wired in parallel, and the other half anti-parallel. The controller generates a PWM and also switches the polarity to select which half of LEDs to light. Usually they have 8 modes.

I think that's probably due to regulations in some 240V countries. Here in the US transformer powered miniature lights were never really a thing, they were always just series strings of lamps fed directly from the mains, when LED strings appeared they used the same arrangement with the addition of a ballast resistor. Some have sections wired in anti-parallel to reduce flicker, some don't. More recently I've seen some multi-mode lights that have electronic controllers but there are still a lot of the plain series string LEDs.

[VK3DRB]

What has LED lights got to do with the birth of Jesus Christ? Nothing whatsoever.

[james_s]

What has LED lights got to do with the birth of Jesus Christ? Nothing whatsoever.

Virtually none of the Christmas traditions have anything at all to do with the birth of Jesus, but that's beside the point. Many elements were borrowed from existing Pagan holidays, some are much more recent than that. Santa's red & white suit came from a Coca Cola advertising campaign, Rudolph the Red-Nosed Reindeer was an advertisement for the Montgomery Ward department store chain.