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How to cut REPLACEABLE LED strings in half and use different colored LED's in them.


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With that out of the way, here are the storebrands and strings I have done this too without problems:

The strings I have modified have come from two places, one of them being Wal-Mart, the other Target.

I'm not sure of the namebrand of the LED's Wal-Mart uses, but these were the 50 count dome style strings, green wire and have a rectifier BUMP on each end of the string. (came in a green box) I've tossed the boxes, so don't recall what brand Wal-Mart uses, I think it was HolidayTime? or ?, just don't recall.

The other string, the Target ones are made by Phillips, these are 60 count LED dome strings and also have a rectifier at each end of the string.

These ARE THE ONLY TWO string types I have ever cut down to 1/2 size, 25 LED or 30 LED per section without any problems.

Actually Steve, believe it or not, these are FULL WAVE strings. It's just that each set of LEDs in the string, on a 50 count string just has it's own FW rectifer attached, that is each set of 25 has a FW Rectifier in the string. At least according to the boxes I just tossed out the other day, says they are full wave in the instruction papers. But who keeps those things?:giggle:

The LED strings I have and have modified came from Wal-Mart, Target, Home Depot, K-Mart or Lowes.

Clay, can you clarify this for me? I was under the impression from your other thread that you were successfully doing this with Full Wave LEDs? And you mentioned a few other brands in your PM. Have you had success with Full Wave LEDs or these other LEDs?

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Steve, at the time I was unsure of the brand or from which store I had bought them and done this too, so I posted the stores of where I bought a lot of the brands I have.

I had to go and look and see which brands I had actually done this too that worked. Sorry for the confusion, but when buying from so many different places and NOT really keeping track of whose string came from which store, I had to do some back checking to see which strings I had done this too successfully.

And as far as I know all those brands are, and were full wave, I would think they would have to be since they dim, fade and do all the other effects and are very bright. Most 1/2 wave sets I have are dimmer than these and they don't fade/dim as smoothly as the ones I mentioned. If they are 1/2 wave, then something must be very different in their design over other 1/2 wave types. The 1/2 wave sets are the ones I don't trust because they are the ones the rectifier gets a little too warm for my liking.

But personally I honestly can not see how any DC current controlled item could only be 1/2 wave, everything I've always built that was to be powered by +/- DC power has always been full wave so I can feed the ~AC~ into the ~AC~ inputs and have + and - DC out along with a voltage regulator and/or resistor to drop the current down.

To be quite honest, I've never used or ever attempted to try and power any DC item from a 1/2 wave. In my opinion, that would be asking for trouble as I can't see how you can convert the ~AC~ to DC +/- used in such applications without overheating or failure problems within the rectifier circuit sooner or later.

The instructions I had gotten with these strings stated they were full wave, so I'm taking the manufacturers word on that one, maybe I shouldn't believe what the instruction sheets had stated?

Edited by LOR-CF
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And as far as I know all those brands are, and were full wave, I would think they would have to be since they dim, fade and do all the other effects and are very bright. Most 1/2 wave sets I have are dimmer than these and they don't fade/dim as smoothly as the ones I mentioned.

I have 3 different brands of HW lights and they all dim pretty close to my FW lights. Some of the stores you listed in your other post, most of the LED strings they sell are all HW. I know Walmart's were HW and Target and HD I think were HW as well. I almost purchased some Philips from Target after Christmas and they were flicker city when I tested them in the store.

The deeper we get, the more I'm thinking were looking at a HW sets, but I may be wrong. :D I have some HW sets that are very low flicker. You can barely notice the flicker, but its there if you look.

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I have 3 different brands of HW lights and they all dim pretty close to my FW lights. Some of the stores you listed in your other post, most of the LED strings they sell are all HW. I know Walmart's were HW and Target and HD I think were HW as well. I almost purchased some Philips from Target after Christmas and they were flicker city when I tested them in the store.

The deeper we get, the more I'm thinking were looking at a HW sets, but I may be wrong. :D I have some HW sets that are very low flicker. You can barely notice the flicker, but its there if you look.

Chris, I don't see this flicker in the sets I modified. Now the UNMODIFIED sets that have the warmer/hotter rectifiers, those I see the flicker you're talking about. These are supposedly full wave, but, then again, made in China and the documentation may be completely wrong, it happens I know.

But I haven't noticed any flicker in these particular strings at all.

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Chris, I don't see this flicker in the sets I modified. Now the UNMODIFIED sets that have the warmer/hotter rectifiers, those I see the flicker you're talking about. These are supposedly full wave, but, then again, made in China and the documentation may be completely wrong, it happens I know.

But I haven't noticed any flicker in these particular strings at all.

I must be buying the wrong lights! I've never had any strings of lights come with documentation claiming them to be full wave, half wave, no wave... Each season I wind up carrying a string of lights or two around the stores looking for a plug to test them. I wish they said it on the box/paperwork!

I hope you don't take this as condescending, but I do want to make sure we're all on the same page regarding half wave/full wave. As well as anyone reading through this who may not have the understanding of electronics you do.

There are half wave strings that fade and dim extremely well (the Walmart 5mm ones for example.) There are full wave strings that fade very poorly (2008's "bad" LEDs.) In fact, of my two favorite big box LEDs, the Walmart Half Waves and the GE Full Waves, I actually think the Walmart ones fade better (without a snubber.)

From what I've learned here at PC, the ability to fade has more to do with the design of the rectifiers. If they use capacitors, they won't fade nicely. That's a whole separate issue from half wave/full wave. Traditionally, full wave sets are a better quality and design. That's why most assume full wave fade better. Generally that's true, but there are exceptions both ways.

Anyway, I rambled. From what some other very smart people have posted here on PC, there seems to be no way to separate a set of Full Wave LEDs without creating a second rectifier for the second string.

My belief is that the cutting works on half wave strings where the first half uses the top portion of the AC wave to light, and passes the bottom portion to the second half. Each of the two rectifiers only rectifies one half of the AC wave and lights one half the string. Thus, when you separate, they keep working as intended.

On a full wave set, both (or all three) of the rectifiers are crucial to the entire string. If you separate them, they may still light, but they're only getting half the job done.

tl;dr REALLY don't think this method will work on full wave LEDs.

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Half wave and full wave and 2 or 3 wire warts and cutting strings in half all comes down to several things. 1) how is the string built. 2) what end results are you going to get or what end results are you going to work to end up with.

Ok, I am making some of my own strings that I am converting over from incan. I am placing the full wave rectifier and the current limiting resistor at the begining. So if I was to split a 70 ct string as the author is talking about. I would have to change the current limiting resistor and add a new rectifier and current limiting resistor. Now if you have a wire wart at the begining and end. It could be either half wave or full wave. Half wave, this would just be the junction of 3 wires. Full wave this would be the juction of 3 wires but also with 2 of the 4 diodes that would create the full wave rectification of the A.C. to raw D.C. A string with 3 blobs I would think that this is two full wave circuits. The middle blob would contain half of the first full wave and half of the 2nd full wave circuit.

But half wave can be with no diodes and 1 or 2 resistors. I just looked at someones string of 25 red LEDs. It had no diodes and attaced to 10 of the 25 LEDs was an 1/8w 470 ohm resistor. All where in series. Out of the plug there were 2 wires and these two wires ran to a socket. A third wire ran from the plug hot to the socket neutral. This 3 wire contained the LEDs and resistors. So the LEDs both produced light and rectified for one half of the cycle.

BTW if I understood an earlier comment. Even if I have LEDs in parallel turned the other way (Cathode and anode swapped end for end) the string would still be half wave. Cause each device would only conduct for half of the wave.

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Steve you may be right. If I can find any of the documentation I'll see if I can find the area that had the statement and take a photo and post it. However, I usually toss that stuff out, right long with the boxes because they{the boxes} just take up far too much space!

I just roll my lights up and tie them with a zip tie for storage, takes up a whole lot less space in my storage totes that way!:)

So no offense taken, I could be wrong that they are full wave, but I am almost positive I did read it in the documentation that came with the strings I have modified.

The grasp of the English language on some of these documents is something to be desired too. I think we need Word Girl to "proofread" them before they go in the box.:giggle:

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Has anyone tried to cut non REPLACEABLE strings such as the one from CDI or LED Holiday lighting?
Please - Don't do it - you will ruin a nice high-end light string that probably costs $10 or more. And void any warranty you might have received as well. Clay might have been successful with the brands that he was using (he mentioned them in here somewhere), but I have no doubt that you will not experience the same results. If you need smaller high-end strings than 70ct, see Valerie. She has 20ct, 35ct, and 50ct FW LED light strings. Edited by B_Regal78
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This was an experiment with cheap LED's which we don't really know if they will work under the stress we put lights under so I would highly recommend NOT CUTTING EXPENSIVE Strings Of Lights....

I tried going back through all of this thread... but got extremely lost in all the text... Clay what were the brands again that you successfully cut? So that everyone knows

Edited by LightsonBeasley
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This was an experiment with cheap LED's which we don't really know if they will work under the stress we put lights under so I would highly recommend NOT CUTTING EXPENSIVE Strings Of Lights....

I tried going back through all of this thread... but got extremely lost in all the text... Clay what were the brands again that you successfully cut? So that everyone knows

Agreed Joe. These "WERE CHEAP RETAIL STORE BRANDS", and I definitely WOULD NOT recommend anyone do this to a more expensive string of LED's!

That said, the ones successfully cut were from Wal-Mart and from Target (Phillips) that worked out in doing this. These strings are prone (Wal-Mart) to rust and socket deterioration when left out for extended periods. I just pulled up the 3 sets I had outside, been there from about 3 weeks before Halloween 2009 and just removed them Feb. 2010 since they started failing, but NOT because of the cuts, they failed because of the rusting problem. The Target LED's, 1 string that I have out still for the same duration is still going strong and no sign of rust on them anywhere. Still burning bright.

I soldered an old socket from another string I had cut all the sockets off of (again Wal-Mart brand) that the sockets had runsted out and they worked fine once more, one that I had a rectifier fail on (one end of) it and made that one from what was a 50ct string into a 25ct string, which is still used on my "test wall" for use with the CTB16PC controllers and I've run the heck out of it with no issues.

But again, these are Wal-Mart and Target brands. Some brands this CAN NOT, NOR SHOULD NOT be done too.

This was an experiment that worked, it may not work under all situations or with all strings, even from the same manufacturer.

Now that I know there are actually smaller LED string available, I'll buy pre-made strings when I need a smaller count string.

When I started messing with this, I didn't know smaller strings were available (and maybe they weren't at the time) when I started messing with these about 2 years ago, so I needed a smaller string count and this idea was born and fabricated.

I guess I was just lucky it worked.

Edited by LOR-CF
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Has anyone tried to cut non REPLACEABLE strings such as the one from CDI or LED Holiday lighting?

It is very easy to cut both 1/2 wave and full wave rectified strings of 70, and 100 count LEDs into 35 and 50 count respectively.

Midway you will find the 3 wires of the string decrease to just two. That is where you make your cut.

You will need to be sure your FWR strings each have a rectification circuit (the "bump" in the wire).

As others have said, this will "void" your warranty.

When I have run short of strings, I use this method. My cut LED strings are working just fine, and it has been 5 seasons of use...

Greg

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Hi Steve:

The C6 1/2 wave rectified were from Animated Lighting. No worry about rectifiers with those!

The FWR were from CDI and Holiday Creations. They (on the 70 and 100 strings) have 2 rectifiers on each string, and can be cut in the middle, as described in my note below. One rectifier powers 1/2 of the string, the other powers the other 1/2.

I have done that with a number of the above strings from these 3 distributors without issue.

I can't comment on GE, but Holiday Creations made the LEDS I purchased from Animated Lighting, if memory serves me...

Greg

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Hi Steve:

I can't comment on GE, but Holiday Creations made the LEDS I purchased from Animated Lighting, if memory serves me...

Greg

I have successfully cut in half GE and Walmart 1/2 wave strings without a problem.

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