# Power through LED strips?

Hi everyone,

I know LEDs require a lot of power, relatively speaking, so I'm familiar with the fact that I can't power thousands LEDs with any reasonable 25A 5V power source for example.

But, what if most of the LEDs are off most of the time?

What if, in my super long strip of 2000 LEDs I only ever have 10 LEDs active at any given time?

Could I have an infinitely (well, for all practical purposes) long LED strip, powered from one end only (no adding power in the middle of the strip), as long as, cumulatively speaking, the number of LEDs lit consume less than what the power supply can provide?

Well, I'll respond to my own question....

Voltage drop is apparently not a function of the consumed power through the system, it's a function of the thickness and length of the conductive material.

So no, even if in a 2000 led system I have 5 on and 1950 off, I can't simply power the whole thing at one end and I have to add power at regular intevals in the strip apparenty.

What about the data line? Could I signal a LED that's 2000 LEDs away?

Voltage drop is apparently not a function of the consumed power through the system, it’s a function of the thickness and length of the conductive material.

But it is also determined by how much current is going through those wires.

So no, even if in a 2000 led system I have 5 on and 1950 off, I can’t simply power the whole thing at one end and I have to add power at regular intevals in the strip apparenty.

You can’t say that, one way or the other.

What about the data line? Could I signal a LED that’s 2000 LEDs away?

The data signal gets regenerated by every LED it passes through, so from that point of view there is no limit. Although there are other limitations.

These are smart LEDs, like WS2812B? They pass the data from part to part, so the limit becomes the refresh rate you want to use. You have to send out 6000 bytes to reach the 2000th LED. Use the fastled.h library.

Add power to your strip in multiple places, you don't want it fusing on you.

The maximum length depends on 1) the gage of the wire, 2) the length of the wire, and 3) the amount of current drawn.

• Figure out the gage of your wire.

• Assume that all the LEDs will be at the end of the string and use the total distance of the string. This is a good approximation unless the LEDs are far apart.

• Calculate the maximum number of LEDs that will be on at any one time.

• Calculate the maximum current by multiplying the maximum number of LEDs by the maximum current for each LED.

• Use any of the wire loss calculators on the net to see the voltage drop. They will ask for the wire gage, voltage used, current, and distance. Make sure you know whether the calculator is using one-way distance or round-trip distance in the calculation.

If the voltage drop is acceptable you are done. If not, you can increase the wire gage, or as another poster mentioned, apply power at multiple places along the string.