Hello, I'm working on a project controlling some RGB strip lights that are over 25 FT away. using an arduino for controls. My question would it be okay to run 25 to 30 FT of Cat6 network PoE for power and controls to the RGB led Strips? The led strips 4 amps in total for each strip at 24v.
Joseph
How much Ohm is a Cat6 / m?
Sorry, / ft I mean.
@ledsyn I honestly don't know I asked google and it said The "± 15%" indicates that the actual impedance of a Cat6 cable can vary slightly, but it should remain within the range of 85 to 115 ohms.
Edit: Google says 24V passive PoE will power an OM series AP up to about 50 meters or 100-150 feet .
I think my CAT6 POE cable is almost that long, and when I checked, it would go 100M.
You are confusing characteristic impedance with DC resistance. Cat 6 characteristic impedance is 100 Ohms, this is critical for its ability to carry data or other high frequency signals but nothing to do with its ability to carry DC power. For its ability to carry DC power you need to know the resistance of the conductors.
Without checking I'm pretty sure 4A is way too much if you are using PoE.
To clarify, you said PoE, so am I correct to believe you are using an ethernet shield at each end to carry the control data? Ethernet uses the green and orange pair for 10/100 ethernet, blue is for telephone, brown for 24V PoE.
If this isn't what you are doing then please explain.
@PerryBebbington I’m use to saying Poe power. Because a lot of my work is in Poe. But no I’m sorry not Poe power just power and data down a cat6 Ethernet.
I have no idea what that's supposed to mean, do you?
As @PerryBebbington already concluded, you're confusing impedance with DC resistance of a cable.
A Cat6 have around 9 Ohm / 100 m resistance. You said up to 30 ft, that is approx 10 m + return, 20 m. 100 / 20 = 5, divide 9 with 5 = 1.8 Ohm. 1.8 * 4 A gives the voltage drop, 6,4 V.
17.6 V is left, can your equipment handle that? Even if you use two pairs for power, there's still plenty voltage drop. Then there's temperature to the equation.
Then it is PoE.
I'm clear from what @josephchrzempiec said it's not PoE, it's using cat 6 cable for power, no ethernet involved.
I suggest you use a higher voltage for the power and place a buck converter close to the load. If you use 50V the loss will be one quarter of what it is at 25V. Do you understand I^2 * R losses?
@ledsyn my power supply is 24v 45 amps. It’s the only one 1 have and I have 3 led strips all close to the same 25 to 30 ft away.
Do you have 3 separate cables?
Is the current for each strip = 4A/3 = 1.33A
So it may be OK
It got nothing to do with how much amp your psu can handle, it's about how much your wiring can take before you get voltage drop. You would be better off with more voltage.
Why don't you invest in regular wires?
It heavily depends on the wire diameter and length of the strip. Lower voltages require fatter wires. I would say 1-1.5 mm or more in diameter would be safe for longer wire. CAT6, per my understanding, has too thin wires. My guess - it will not be enough.
Another typical suggestion - use power injection in the middle and end of the strip. You also should power led strip directly- not through Arduino
For addressable LED strips, I sometimes also use a signal amplifier- they are cheap on AliExpress.. However, looks like, this is not your case.
@jim-p I’m sorry I had to fix my original post. It’s 4 amps each strip. They are not addresssble leds.
@1Pats yes a power injector.
@ledsyn That is true. However I only have that power supplies.
Afaik you have three choices, to either connect more wires in parallel, get better cabling, or move the PSU to the connection point for the strips.
OK 3 strips 4A each
Is there a separate cable for each strip, so 3 cables?
4 amps 24Volts ->a bit less than 100 wats x 4 strips - up to 400 wats.
Addressable or not - Cat6 will not be enough, plus you need an adequate power supply.
To avoid burning - 20A at minimums, especially, if you use a Chinese-made power supply. Your 45A would be enough, but fat wires are needed for each strip.
Exist many tables linking amps to diameter and length. Here is one example
https://www.bluesea.com/support/articles/Circuit_Protection/1437/Part_1%3A_Choosing_the_Correct_Wire_Size_for_a_DC_Circuit
You can do precise calculations. My quick response is intuitive- recently I had a project with many large-size LED strips and observed similar problems.
@jim-p Yes. One power supply for all.
@ledsyn All lights are in parallel.