Re: Altering LED light strands for layout use

Vollrath, Don <dvollrath@...>

I wouldn’t mess with trying to increase the brightness of the individual LEDs themselves as you would be altering their current… and lifetime. But yeah… if you bypass one of the LEDs the current of others would increase, but with little noticeable increase in the brightness.


You would be better off simply rebundling them to be two together to yield similar brightness of each C7 type bulb in a continuous string from ‘house to house’. If you don’t need 25 locations or want more linear space between houses, cover (paint?) the LEDs you do not use.


But Yeah, all the individual voltage drops of each LED (apparently in your case 25 in a series string) lead up to 65-80 volts of total voltage drop, and there is a resistor or inductor somewhere in that string to limit the current from the 120Vac plug. Look for a rectangular ‘blob’ somewhere in the wiring string. I might be molded into the male plug end. Get out your ohmmeter and find it.


But remember that you are dealing with something designed for 120Vac. LEDs are diodes that conduct current in only one direction. The strings might be arranged where one grouping of 25 carries the (+) current and the second grouping wired in anti-parallel carries the (-) current. Each LED tends to ‘sparkle’ or flicker at 30 Hz from 120V, 60 Hz power.

I have also seen 2 LEDs connected anti-parallel within the same plastic housing to directly work from AC current. Still need a mechanism to limit current.


Either way, it is difficult to fiddle with commercial LED wiring without knowing for sure what and where the current limiting element(s) are located. Be careful to not alter the actual LED current and to not create a fire hazard for your household. Anything that plugs into a wall outlet should be UL listed according to your insurance company.




From: WiringForDCC@... [mailto:WiringForDCC@...]
Sent: Friday, January 09, 2015 10:09 AM
To: WiringForDCC@...
Subject: [WiringForDCC] Altering LED light strands for layout use


I hope this is a good place to ask this question.
I incorporate Porcelain houses into my Christmas display.
The houses are designed for C7, 7 watt bulbs.
I purchased several strands of LED Christmas lights to use in my display.
I found that 2 bulbs gave about the same of light as the C7.
I know little about LED lights.

I am assuming that the stand of 50 lights in 2 power districts have build in resistors.

IF a bulb is removed the complete section is DEAD.

Now for the question,
Is it possible to remove a bulb, connect the wire ends, as if no bulb existed?
IF a group of 25 LED were to be stripped down to 12, keeping math relatively simple, would the LED be brighter?
I do not know where the resistor is in the stand, would it need to be replaced do a different size and or would the LED be brighter with the reduction of number of LEDs lit?

Again, not knowing LED physics, am I looking at any fire hazard with this thought process?

Just to add to the reasoning of my question, the LEDs on the strand are too close to each other and I have about 2/3 of the lights under the layout doing me no good.  I want to decrease the number and increase the brightness.

Thank you for all input and suggestions.

Cameron D
NE Florida


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