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Jetmech

Splicing LED M5 mini lights

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Jetmech    0

Has anyone tried to splice M5 mini light full wave rectified Christmas lights?  Here is my issue....I have a 100 count light string.  I need to splice 20 lights of red into the white.  Can I remove 20 lights of the white and insert the 20 lights of the red?  It would make my display much neater and easier to populate the lights.  The lights are 3 wired full waves.  Thank you for any information/suggestions anyone is willing to share. 

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dibblejr    377

I would think if they are the exact same light strings and you cut in the exact same place that should be fine but I don't hold me to it. If not exactly the same I do not know the outcome. Fire, electrical shock, controller damage?

JR

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George Simmons    1,154
1 hour ago, Jetmech said:

Has anyone tried to splice M5 mini light full wave rectified Christmas lights?  Here is my issue....I have a 100 count light string.  I need to splice 20 lights of red into the white.  Can I remove 20 lights of the white and insert the 20 lights of the red?  It would make my display much neater and easier to populate the lights.  The lights are 3 wired full waves.  Thank you for any information/suggestions anyone is willing to share. 

I believe the answer is no.  Different colors have different voltage requirements.  I suppose you could try with a couple strings you're willing to sacrifice at the altar of knowledge.

59 minutes ago, TheDucks said:

Why not just swap the LED bulbs?  No splice required

Commercial quality full-wave LEDs are sealed.  Not having replaceable bulbs is one of the main things that make them far better quality than retail LEDs.

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TheDucks    28
1 hour ago, George Simmons said:

I believe the answer is no.  Different colors have different voltage requirements.  I suppose you could try with a couple strings you're willing to sacrifice at the altar of knowledge.

Commercial quality full-wave LEDs are sealed.  Not having replaceable bulbs is one of the main things that make them far better quality than retail LEDs.

Makes perfect sense, having lost 1 season strings to rusted bulb leads :( . I now bring thos cheap strings inside the heated room and leave them ON 24hrs before stashing them for the summer.

I did not need 'brighter', so I ignored the full-wave reason for spending lots more for commercial grade

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Jetmech    0

Thanks for the thoughts, we will probably try to sacrifice 2 strings to see if that will work.  We did buy the commercial grade so they are sealed and we cannot change bulbs like the cheaper ones.  

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Yes you can as I did this on 5 different strings of sealed lights. You must keep the same number of bulbs in the string and more importantly keep the same number of bulbs between the resisters.

George is right about the colors having different voltages but I found no difference in the brightness that the eye can detect. You will find that the blue bulbs are the worst for failure rate.

I solder and shrink the splices as well as liquid tape them.

One last thing, you must keep the polarity correct or the lights will not light where you splice.

John

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Jetmech    0

Thanks everyone for the info, John, I have done a little research and read somewhere that the color of an LED light in determined by the doping material of the LED when made. I agree with you that you must pay attention to the polarity when splicing in a new bulb. I am going to try some experiments on some strings of lights this weekend. I will see if the voltage is different across the different colored LED lights. The blue lights do tend to be the worst failure rate, you are correct. If the strings have resistors in them that may account for the different voltages on the lights. when i get my results I do my best to post them.  Thanks  Jeff.  

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Jetmech    0

Hi everyone, Have some info for people who may be following this post. Made some electrical measurements on a white 70 count string this weekend. The string is divided into two sections of 35 LED's each, nothing new there. I measured the voltage drop across one of the LED's and found it to be 2.68 volts. The current flow through the LED's was 19 milli amps, using good old Ohm's law I get a "bulb" resistance of about 141 ohms. If you add the bulb resistance together you get around 4900 ohms for that section. The label on the string of lights has a total current flow for the string at 40 milli amps. With 2 sections making up one string that makes sense, 20 ma times 2 will make 40 ma. I may try to supplement a resistor in for a number of LED's I will remove from the string and see if that works. Hope this may shed some light on the subject of splicing LED lights. Thanks again for all the inputs to this post.  Jeff

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GRG    1
19 hours ago, Jetmech said:

Hi everyone, Have some info for people who may be following this post. Made some electrical measurements on a white 70 count string this weekend. The string is divided into two sections of 35 LED's each, nothing new there. I measured the voltage drop across one of the LED's and found it to be 2.68 volts. The current flow through the LED's was 19 milli amps, using good old Ohm's law I get a "bulb" resistance of about 141 ohms. If you add the bulb resistance together you get around 4900 ohms for that section. The label on the string of lights has a total current flow for the string at 40 milli amps. With 2 sections making up one string that makes sense, 20 ma times 2 will make 40 ma. I may try to supplement a resistor in for a number of LED's I will remove from the string and see if that works. Hope this may shed some light on the subject of splicing LED lights. Thanks again for all the inputs to this post.  Jeff

Would one have to be particular about the wattage of the resistor?  It would be really nice to be able to shorten led strings by adding a resistor.

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TheDucks    28

use Ohms law

P+I*E

where E is the drop needed to make up for missing (removed from series) LEDS

.020A for I

double the result for basic  derating  (I would be surprised if 1/2W rating was exceeded  (bigger W is only a bigger device to deal with. It would work just fine)

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Steven    78

Red and amber LED's are about 2 volts.

Green, blue, purple, white are about 3.5 volts.

What this means if you remove 20 white bulbs (that are one series segment!), you can replace it with about 35 red bulbs (in one series segment). If you use less than 35, it will still probably work, but they may run hotter, which mean they may not last as long. If you have some sacrificial strings you can test, I would leave them plugged in overnight to see if they are still working the next day.

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Jetmech    0

Sorry everyone, have been busy haven't been able to play with the lights. Hi Steve, I checked the drop across one LED on a 70 count string 35 per section of a purple set and got only 1.95 volts the white shows a drop of about 2.68 volts I am going to try this weekend to check the drop on red, green, blue and amber colored lights. I am making variable resistor tester to use for checking what size resistor to use and install in the string. the string you tested can you tell me what count it is and was it a full wave type. Thanks Jeff.  

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