Nedd input regarding. voltage drop in a 4-wire supply cable RGBW led lights

I'm about to purchase cables and power supply, plan a large installation of led lighting. As primary indirect light 80m2 living room and kitchen and entree.

I will use 4x5 meters 24 Volt Warm White 2800K 2640 Lumen/m 24Watt /m CRI>Ra95 and RGBW cool white CRI>Ra85
Decentral power supply and Controllers, and plan dimming all the led strip by approximately 50-80 % under normal conditions. This should help keep the part temperature down and extend the led chip radically.


I need some input regarding. voltage drop in a 4-wire supply cable RGBW led lights.
I am quite familiar with the formula for calculating the voltage drop, but are unsure how it will be calculated by RGBW led lights with 4in1 led chip?
http://www.gugtech.com/english/ProductView.asp?ID=365&SortID=160



I need to install a larger part of high power 12V led strip 19.2 Watt/m. They are mounted in 5 meter lengths. 7 meters from the main power supply and controller.


5 meter led lights a 19.2 Watt / m = 96Watt / 8amp
Acceptable voltage drop 5%


This would normally mean that we should spend a minium 6mm2 / 10AWG cable.


But I think, the power consumption of a RGBW are well spread over the 4 colors / wires so in my understanding will never have a consumption of 8amp per wire in the cable, but just a 1/4 per wire. which will mean 2A per wire which is a huge difference and would mean that there could be used 1.5mm2 / 16AWG


Am I mistaken, or did I on to something?


P.S. I know it would be preferable to use 24V Led light, and it is also planned with the rest of the installation unfortunately they were sold out in 24 volt

psstdk said:

I need some input regarding. voltage drop in a 4-wire supply cable RGBW led lights.
I am quite familiar with the formula for calculating the voltage drop, but are unsure how it will be calculated by RGBW led lights with 4in1 led chip?
http://www.gugtech.com/english/ProductView.asp?ID=365&SortID=160


But I think, the power consumption of a RGBW are well spread over the 4 colors / wires so in my understanding will never have a consumption of 8amp per wire in the cable, but just a 1/4 per wire. which will mean 2A per wire which is a huge difference and would mean that there could be used 1.5mm2 / 16AWG

Click to expand...

I do not understand what you are confused about. The current is flowing in through the white, red, green, and black wires, and out through the blue wire. The voltages over the different channels may be slightly different, but for simplicity purposes you could assume they are the same and still obtain a close estimate. Much of the conductor length will be through the strip board, and you really do not know exactly what the ohm losses will be through that (unless you care to test it with an ohm meter).

I would say it may be preferable to use a thicker gauge for the positive wire, since all four channels will be flowing through it.

I am not going to take the trouble to do an exact calculation, but overall my feeling is that the voltage drop is going to be about 10%. Obviously, if you are using a constant current driver, the supply voltage will automatically adjust for the voltage drop. There will be no decrease in brightness, but it will consume slightly more power and the overall efficiency will be decreased.

Your thinking is exactly correct. You only forgot one thing: the common wire will carry the sum of the R, G, B, and W currents.

And given the source, the specs (few as they are) are likely to be wildly optimistic. I guess that's two things.

Oh, and you didn't allow for the voltage loss along the length of LED strip. That's just three things. Even if you figure two amps at the start of the string and zero at the end, averaging to 1A, the voltage loss along 5m of string would be awful. Okay, that's a WAG. Let's do a best-case scenario: two sided circuit, 1 oz. copper, bottom is return, top is 4 traces for various colors. If the strip is 13mm wide, and we allow 1mm for spaces, tolerance, etc., that leaves 3mm each for the traces, and 12mm on the bottom for the return. A trace 3mm wide and 5m long in 1 oz. copper carrying 1A would have a voltage drop of 0.8V. That all by itself exceeds your 5% voltage drop allowance of 0.6V, and we haven't even considered the return trace or the wires. And in the absence of evidence to the contrary, I'd bet that even that calculation is wildly optimistic.

I hate to say it but I think you are likely to be seriously disappointed with your results if you build this thing, especially if you invest a lot of money in it. Are you sure you can't wait for the 24V strings to be back in stock? You can allow twice the voltage drop at half the current, so it's better by a factor of 4!

Oh, and there's no way those connectors are going to work at 8A. I'd guess they are going to be a reliability problem at 2A. I wouldn't want to push them beyond 1A.