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Converting old to New with LEDs


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I am looking at taking some of my old incandescent stuff and making them new again by putting LEDs on them. For this, I have 2 questions:


1. To convert candy canes, I need about 4.5' of red LED M5. Can I take a 25' strand, cut off what I need and add a male plug? So ending up with 5 candy canes from 1 LED strand.


2. My Santa + sleigh have red, green, and white bulbs, all white wire. They are mixed around a bit. Here is where I need suggestions... I cannot find any M5 LEDs with white wire (except with white bulbs). I am also unsure the best way to get 14 green, 9 red, and 32 white LEDs to the same strand. I once heard of covers that would turn a white LED to another color, but cant find them anymore. Paint the cord white? Cut and splice the 3 colors into 1 strand? I want this to look right, so any creative thoughts would be appreciated! Thanks

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hey doc,


I'm not sure about the candy canes.  I don't know why that wouldn't work though.  your just making a short string.


as far as the covers you are talking about   http://www.christmas-leds.com/category_v3.aspx?categoryID=336 has them

they are called combo clips.  call Valerie and let her know what size bulbs you are wanting to cover and she can get the right size.


you just get white leds and cover each one as you need. 


good luck

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Thanks! Any idea if they look as good as a regular LED bulb? I've never used them, so I'm not sure if they will lose much brightness by using the cover.

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Doc, you need to learn basic D.C., Ohms law, PIE, and Kirtchov's Law (my spelling might be off a wee bit). Kirtchov's law says that the total voltage drop must equal the total voltage applied to the circuit. So lets say you have 35 LEDs in a circuit. Each LED must drop a little over 3 volts each. Now lets say you only need 10 LEDs in a string. Now you looking at 12 volts being applied to each LED. What do you think is going to happen?


Now to add another monkey wrench into the mix. Most LED strings do not create clean D.C. so you must add a little english to the mix and use what is called RMS.


this is not for the faint at heart. I have converted several ican strings to be LED strings. By adding in the english of RMS I was able to do the conversion from ican to LED. Oh and what color LED you are using will have an effect on the calculations. Any one who says just cut and put on a plug is full of dodo. Now there are exceptions to all rules. And if you cut at a wire wart then there are chances you can change say a 70 cnt to a 35 count. Or something like that.

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Well, it is Kirchhoff. I am a 2nd year engineering student, so I am pretty familiar with all of that. I just for some reason tend to overlook such things when it comes to applying it to what I'm actually doing. As far as I know, LED strings, being AC, do not have any electrical components except fuses. So it shouldn't matter how short the line. That being said, I think I just answered my first question!

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First and foremost, LEDs are D.C. They are a diode and will only conduct when the voltage is applied in the correct side. I believe we call this polarity sensitive. All LEDs are rated on the spec sheets using pure D.C. as the source. We are now working in a dirty D.C. environment. You can not use a electrolytic cap. to filter the dirty D.C. LED strings used to add caps. but those strings would not fade or any of the other effects properly. Some people actually had their strings burst into flames. So all makers have for the most part stopped making strings with the caps.


So with dirty D.C. you have to use RMS as a factor in making your own strings or shorting them. Most of the LEDs we work with have a max 20mA value. RMS of this is about 14mA. And this is what  I look for when testing to make sure I have the right resistor value in series with the string of LEDs. Also apply the RMS to the voltage to. So 110V X 1.414 = 155.54V.


I also mentioned that different color LEDs have different voltage drops. Red, Orange, and Yellow all drop 2.2 volts. While all of the others drop around 3.3 to 3.6 volts. This all has to be taken in account to make it work. And work more than half of a season. There is a lot more involve than making sure all of your LEDs are pointing the same direction.


I am 55 yrs old, hold an Amateur Radio Lic of Advance class. Been in the business of fixing electronic devices all of my life. And have more experience than you could have as a 2nd year engineer. Cause if you had some more experience you would not have only noted fuses. Some strings actually have rectifing diodes. But they all have current limiting resistors or voltage dropping resistors. Depends on who you are talking to.


You really want help. drop another post with the number and color of the LED string you want to build and I will help walk you through it.

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they seem to look fine.  you don't lose any color with the caps.  my best suggestion is make sure you get

brite white leds.  they look the best and you can definitely see the color difference with the caps.  I used

some off white leds and there wasn't much of a color difference between say orange and red.  off white just

seems to dull the caps. 


let Valerie know what leds you have and she used to have a little sample pack you can get.  its got like 4 or 5

caps that you can try out.


I've ordered several hundred and have been happy with what I ordered and how they look on my wireframes.  just

needed bright white instead of off white leds.  lesson learned.

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