# LED Christmas Lights



## Noyb (May 25, 2005)

We got tired of trying to fix Christmas lights, so my wife bought all new LED Christmas lights.

The attached picture is still under construction &#8230; 
But I&#8217;m surprised by the intensity of these LED Christmas Lights.

We had one problem .. 
We couldn&#8217;t use my X10 lighting controllers so we could switch them on or off remotely.
The X10 controllers feed a little current out when turned off &#8211; 
so it can sense if something plugged into it - is being turned on.
This current is enough to light the LEDs in a dim glow when the controller is turned off.

I&#8217;m curious if these will be more reliable than the incandescents.
And, Since they are still in series .. What happens if one goes bad.


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## JohnWill (Oct 19, 2002)

Well, LED's are conservatively rated at 50,000 life, and usually much more. So having them burn out is probably not an issue. 

For the X-10 controller, try putting a small lamp on the same circuit to "help" it sense the current. You can also use the relay controlled appliance module, it works with nothing plugged into it.


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## Noyb (May 25, 2005)

I tried the X10 relay .. It also senses the output same as the dimmer modules.
I thought about loading the output with something other than the LEDs ... Just haven't tried it yet.

I'm thinking the current drain of these LEDs is almost nothing .. as compared to incandescents.


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## JohnWill (Oct 19, 2002)

I just plugged in one of my ancient Radio Shack appliance modules, it turned on and turned off with nothing plugged into it.

The current drain of the LED's is probably in the 20ma range.


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## Noyb (May 25, 2005)

I'm guessing that the draw of the high intensity LEDs might be as much as twice the normal .. = ~ 50ma ??

The problem with the X10 modules .. They do turn on & off .. but when off, there is a residual Dim Glow from the sense current.

I'm waiting on a Cat Scan .. Last year they liked to hide underneath .. I think it was for the heat.
They will be disappointed this year.


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## Noyb (May 25, 2005)

Seems like anything else plugged into the X10 module .. other than more LED lights ...
will stop the residual glow when turned off.
The LED sockets still look a little "cheap" and I'm suspecting this will be the only source of problems now.


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## JohnWill (Oct 19, 2002)

You just need something that draws a bit of current. I tested with an LED nightlight, and indeed it does stay on dim when the appliance module is off.


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## Drabdr (Nov 26, 2007)

Are you sure they're in series? Have you tested? They've pretty much distanced themselves from series for the most part.

Edit.. What about adding a timer plug shutoff for when you want them completely off? I'm assuming that is what your quandry is. Am I wrong?


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## Noyb (May 25, 2005)

YES .. Obvious from the wiring - and - unplug one and the series goes out.
There would also have to be a power supply to drop the voltage to drive the LEDs in parallel.

Eventually there will be an incandescent lamp, or two, plugged in to load the sense current.
But the draw is so little .. who cares if they're not fully off ?


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## Drabdr (Nov 26, 2007)

Noyb said:


> YES .. Obvious from the wiring - and - unplug one and the series goes out.
> There would also have to be a power supply to drop the voltage to drive the LEDs in parallel.


Well... I was just kind of wondering. I figured you had that part figured out already. But... I don't understand the power supply thing.

The LED lights may need a very specific voltage. Thus, when one is removed, it changes the amp load, and thus the voltage (fixed supply) would change, so it shuts off. Possible or a Christmas wish?



Noyb said:


> Eventually there will be an incandescent lamp, or two, plugged in to load the sense current.
> But the draw is so little .. who cares if they're not fully off ?


I was wondering about this too. Could it be that 'specific' voltage thing? Incandescent are essentially resistors, so you can vary the voltage. I don't think LED lights work the same way. I believe they require a fairly specific voltage. I'm assuming these lights are DC voltage?

I wonder if mimimal voltage supply might shorten the life of the bulbs.

Again... just academic chat now..

John, why does the X10 controllers allow for amp pull when turned off? I understand the controller would pull some minimal load, but why is there not discrete shut off on the output of the controller?


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## Noyb (May 25, 2005)

If a device, like a lamp, is plugged into a X10 controller module .. it can be turned on manually.
There is an output from the module that can sense if the device is being turned on manually ... This will turn on the x10 module.
Apparently, this "sense" current is enough to dimly illuminate the LEDs .. but not incandescents.

Actually, Incandescents are a negative resistors.
the less voltage .. the less the resistance .. so they can be constant current loads in a certain range .... "just an academic chat"

You're right - it takes a certain voltage to illuminate a LED ... then they act like a zener diode.

But now you really got me curious ... LEDs should be DC ???
How is this handled from a AC source ???
I may have to dig out some meters .. and look see.

http://www.smarthome.com/about_x10.html


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## cwwozniak (Nov 29, 2005)

Noyb said:


> LEDs should be DC ???
> How is this handled from a AC source ???


The plug may have an internal single rectifier diode to give half wave pulses of DC to the string of LEDs. No need for any kind of filter capacitor; the LEDs would just strobe at the 60 Hz (North America) line rate.


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## Noyb (May 25, 2005)

I wondered about that also .. So I took a quick look at the male plug, it only was two wires coming from it.
If a diode was in the plug &#8230; then the output of the string &#8211; for the next string - would be DC
This would cause possible polarity problems for the next series string.
Also, any incandescent plugged into the string would only get half power.
Since there&#8217;s only two wires coming from the plug, they did not wire around a diode in the plug.

As I remember, an LED does not appreciate being fed reverse polarity power.
Back when I retired, it was impossible to get this much light out of an LED, especially Blue.
I&#8217;m thinking the LED has a diode, or 4, internally .. Or it just doesn&#8217;t care about being fed AC anymore.
Somebody&#8217;s invented something new since I retired.

I haven&#8217;t loaded the sense current yet .. so when it shut off last night &#8230;
It went into it&#8217;s Dim Glow sleep mode.
I'm wondering if our cats appreciated the night lite.

The only problem this caused was in my wife&#8217;s mind.
She was convinced it wouldn&#8217;t work from an extension cord and had to be plugged straight into the wall.
I let her continue the assembly .. Then when she wasn&#8217;t looking .. 
I put the X10 module back in and the extension cord &#8230; and said .. Don&#8217;t worry bout it.

It past the Cat Scan ..


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## cwwozniak (Nov 29, 2005)

Is the socket for adding strings on the back of the plug or at the far end of the string.

If it is at the far end and there are only two wires out of the plug, I can't see how it would work, unless ... there are only two wires up to the first light and then you have three wires running from light to light.


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## Noyb (May 25, 2005)

The string female connector is at the far end of the string - only with two wires.
Also .. Each LED socket only has two wires in a series arrangement.

However they built the LEDs or whatever tricks they used inside the LED bulb ... They must be working on AC.

This wasn't what I was originally asking ... 
But it's getting interesting .. thanks to Dabdr's AC/DC comment


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## cwwozniak (Nov 29, 2005)

I found an article from last year where someone did some analysis of a Philips 60 LED set. The photo on page 2 shows two wires running past each socket and a third wire running into and out of each socket.

Gotta love the US patent system. Looks like somebody got a patent for powering a string of LEDs from AC using a rectifying diode feeding a filter capacitor.

Patent title: LED Light String with Half-wave Rectifying and Filtering Device
http://www.faqs.org/patents/app/20080231202


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## Noyb (May 25, 2005)

I understand the two wires running past the LED socket .. this is to provide full power at the end of the series string.

Since Ya'll made me do it  ... I got out the instruction sheet ... it says ...
Replace lamps only with 2V, 0.04W &#8230; or the 3.4V, 0.068W Spare LED Lamps provided.

Notice .. both draw 20ma


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## Drabdr (Nov 26, 2007)

Interesting indeed.... a good thread. Thanks for the pictures and the links. The web is a wonderful thing . A two page review of christmas lights.:up:

An interesting notion about the 60hz being at the point of perception. Noyb, have you noticed the "flicker" discussed in the article?

I find a day is good when I have learned something.. great if I have learned several things. Today is shaping up to be a great day.


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## Noyb (May 25, 2005)

Its all Yall fault again ... You got me curious and made me do some work.

Apparently the instruction sheet is wrong ??
The LED avalanches hard at ~2.0 VDC  Another color was 1.9VDC
It looks like full intensity is achieved at about 20 ma
There is no reverse current when the polarity is reversed.
Im not going to try to measure the reverse break down ...
I get very nervous over 24 volts nowadays.

The instruction sheet is very specific  
Do not reverse the lamp in the socket and match the latching tab.

The hard avalanche makes me wonder .. Wheres the resistor ??
Just what I needed .. Another puzzle


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## cwwozniak (Nov 29, 2005)

Noyb said:


> I get very nervous over 24 volts nowadays.


It's not the voltage that will kill ya, it's the current. 

EDIT: Do the short wires from socket to socket have any measurable resistance?


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## Noyb (May 25, 2005)

But it takes voltage to push current.
NO.

Anyway .. We've notice the cats have not napped under the tree this year.
We're thinking it's because there's no heat.

We have an outside cat that comes in to visit and play.
She was wanting to play with and climb the tree.

Not wanting to grab the spray water bottle - and spray around something over 24 volts ..
I discovered another technological break thru.

A can of spray air scares them just as bad .. if not worse.
She leaves looking like she's just been electrocuted.


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## paisanol69 (Sep 7, 2005)

Noyb said:


> But it takes voltage to push current.
> NO.
> 
> Anyway .. We've notice the cats have not napped under the tree this year.
> ...


The canned air wont work for me Noyb

My cat gets a small bowl of milk, with just a touch of spray whipped cream, before bedtime every night. He would definately respond the wrong way to a can of compressed air!!! (and he's not lactose intolerant, and weve been doing this for 5 years and hes as healthy as a bear!!...11 years old now)

I dont have the heart to squirt him with water...so I usually take off my ball cap and shake it, and he runs for the hills. Never had to throw the cap at him yet!!


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## flaflashr (Dec 9, 2008)

I noticed the same dim glow. I really don't care that it does. H

owever, I am concerned about possible damage to either the X10 or the LED light strings, or possible fire hazard.

Does anybody know if this is a real concern?

Thanks,
JimR


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## Noyb (May 25, 2005)

I ran mine for several weeks with the dim glow .. no problem.
Our Cats have not slept under the tree this year .. We assume it's because there's no heat.

A Couple days ago, We added some incandescent lights to the X10 in parallel with the LED lights.
That loaded the sense current and eliminated the LED glow.

The sense current from the X10 is always there .. I can't see how this would be an additional problem or safety hazard.
I've been curious what the output voltage and the short circuit current is - when the X10 is turned off.
This would tell us what the equivalent output circuit is when the X10 is turned off.

And .. Welcome to the TSG forum


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## JohnWill (Oct 19, 2002)

There is no possible damage to the lights or the X-10 controller. Truthfully, with the small amount of power that the lights draw, you might just consider leaving them on. I have a string of 50 of them on a mantle decoration, they draw 4.8 watts, less than a typical nightlight! I doubt that will break the bank. 

I have an X-10 controller on the 300 on the tree, and they don't have any noticable glow with the unit off.


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## cwwozniak (Nov 29, 2005)

Noyb said:


> I've been curious what the output voltage and the short circuit current is - when the X10 is turned off.
> This would tell us what the equivalent output circuit is when the X10 is turned off.


FWiW, it looks like someone from Cornell University has posted the schematic diagram of an X10 LM465 lamp module.


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## JohnWill (Oct 19, 2002)

Yep, I have one of those I got out of a magazine many years ago. The TDR is where the leakage comes from I would imagine. An ID on the IC would be real useful to understand fully, some kind of decoder...


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## Noyb (May 25, 2005)

OK .. Ya'll got me curious again .. so I messed with something over 24 v
I&#8217;m pleased to report that I&#8217;m still alive .. but a nervous wreck 

The open circuited output voltage of the X10 module when off - is the line voltage (117VAC in my case)
The Short Circuit output current is .401 ma
Since I can&#8217;t measure AC current .. I used a 1/4w 1Kohm resistor (fuse) for this measurement.

This would mean the equivalent output circuit would be 117VAC thru a ~~ 300K ohm resistor.

I would have thought the open circuited output voltage would have been less than the line voltage.
Those LEDs must be Glowing with almost nothing feeding them.


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## Noyb (May 25, 2005)

Since were on the subject of LEDs .. and other weird stuff ... I thought Id pass this on.
I never did like a desk lamp near my Computer  
They seemed too bright - or I could see the lamp.

Several months ago I was at our local Menards Home Improvement store ... 
http://www.menards.com/ ... and I found some LED desk lamps.
They have just enough light .. but you may want several .. 
I found these on sale at $8.00 each.
But they have a cheap on/off line switch that will be a pain to get to - to turn off.

Since they run from a power brick, they do not have the residual dim glow when run from an X10 module.

But here again  Menards to the rescue.
Our Local Menards also has these Smart Strips at about half the online price
http://www.smarthomeusa.com/ShopByManufacturer/Bits-Ltd./Item/LCG5/

Now .. When I turn off my computer 
The Smart Strip shuts off my desk lamps and a few other peripherals.

How would have thought to look at a home improvement store for computer stuff ??


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## hewee (Oct 26, 2001)

Electricity Usage Monitoring Power Strip

But the P4460 - Kill A Watt EZ gives more info and you can still plug it in to your own Power Strip.
Or I guess it you wanted to know all that you have hooked up to you Power Strip cost to run the plug it into the Kill A Watt EZ.


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## Noyb (May 25, 2005)

Kill A WattEZ looks interesting .. But not sure I liked the prices.
I'll look for one the next time I'm at Menards


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## JohnWill (Oct 19, 2002)

I bought the Kill-A-Watt for $20 a year or so ago, very handy gadget to have around.


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## hewee (Oct 26, 2001)

You can get it cheaper a lot of places so do a search. Now the Electricity Usage Monitoring Power Strip is the newer on that may be harder to find then the other two.

But I like the Kill A WattEZ I got. Cost more then the one John got but it does a little more or makes it more easy to use.
Now you got to leave it pluged in to get your average cost on thing that are plugged in all the time like your riffer that can be using power all the time but uses more when the compressor kicks on. But still it takes so many days to adjust to get a better average. Other things are harder like I did the coffee maker. It is always plugged in and has a clock so uses power. I then make a pot of coffee and it tells you the cost. I know the cost a year is a lot less because it is on once a day to make a pot of coffee and the rest of the time it is plugged in it is only for the clock. 
But still you can find out how much power things use and how much things use that are turned off like TV's etc that so can use a lot more power then you think even when turned off. 
Then things like the cable tv box and cable modem always use power even when turned off. All the things you got that are cordless you plug in to charge up. If you take that phone or what ever out of the charger it will not stop using power but it only uses less power.


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## JohnWill (Oct 19, 2002)

The basic unit will compute KWH over time.


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## hewee (Oct 26, 2001)

Well to late now because I got the Kill A WattEZ or I guess *Easy* for the EZ one.


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## JohnWill (Oct 19, 2002)

I looked at that unit, couldn't see it did anything my old one didn't except compute the dollar value from an entered cost per KWH. I can do that quite easily from the raw data, so that didn't seem worth much to me.


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## hewee (Oct 26, 2001)

Well it was the compute the dollar value part I wanted so I had to. it tells you the cost... total, yearly, monthly, day, hour and just makes it easier to use because all you need to do is put in the cost per KWH and forget about it. Well the cost per KWH is not the same all year because you got the summer and winter rates.


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## K7M (Feb 27, 2000)

I read this thread and I was very interested in the Smart Strip you mentioned. I did some research and found the 7 outlet strip at our local Ace Hardware store (Rocky's). I am using it for my component stereo. I have the pre-amp plugged into the control outlet and my amps into the switched outlets. I have outlets on the back of the pre-amp but they do not handle the current of my amps, ( I have had to replace the switch a couple of times).. This is the ideal fix. Thanks.


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## Noyb (May 25, 2005)

A couple of year ago .. I posted a question looking for a 5v relay component.
I was making a USB controlled Surge protector .. When the 5v from the USB would turn on the Surge Protector.

I was looking for a source for an optically controlled solid state relay.
The ones I was using from my parts box - predated Computers.
Someone pointed out that this was already patented.

John Will answered with the Smart strip.
I think he got his from Radio Shack .. Before they quit selling the good stuff.
Thanks to John .. When I saw the ad for Menards Smart strip .. I knew what I was looking at ... 
and probably broke a few speed limits on the way.

I was making a fast trip thru Sams Club today .. Getting some Printable DVDs ..
And I saw some Surge protectors .. That were remotely controlled. 
http://www.samsclub.com/shopping/navigate.do?dest=5&item=410808

I didn't see any Kill A WattEZs … Darnit.

I hope the guy that started this Christmas Tree thread doesn't mind if we hijack it with all this other good stuff.


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## JohnWill (Oct 19, 2002)

In case you want to control that stuff from the other side of the world... 

http://www.cpscom.com/gprod/cps.htm


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## Noyb (May 25, 2005)

*Merry Christmas USPS*  Now Im looking for a scale.
Many of our Christmas cards are being returned due to insufficient postage.
Seems like theyre just a hair over 1 oz  
probably due to the huge sticker the USPS put over the address.

Now I'm having to coexist with a furious wife.
This is enough to make a customer go Postal


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## RockinRonny (Dec 13, 2008)

I have a sting of LED lights I bought last year and onl;y about half of them will light this year. What gives? I thought that these lights were supper long lasting! Any ideas on how to trace and correct the problem?


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## Noyb (May 25, 2005)

?????????
If it's the entire string ... I'd check the fuse in the plug


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## RockinRonny (Dec 13, 2008)

Only about 50 %.


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## JohnWill (Oct 19, 2002)

You have a loose bulb or broken wire. Inspect them closely and you'll probably see it.


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## JohnWill (Oct 19, 2002)

Opened at thread starter's request.


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## Noyb (May 25, 2005)

Time to get the tree out again.
My choice to get all new LED lights last year looks like a good choice ... They all still worked.

My wife likes to assemble the tree and add the lights as she adds branches ... 
And she likes lots of lights .. All the way to the trunk of the tree.
Can you tell, There's a bunch of lights that I didn't have to fix.


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## JohnWill (Oct 19, 2002)

I bought new lights last year as well, all LED. They are much more robust than the old style that I was forever tracking down dead strings!


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