Choosing Wire Cross Section for 12V DC Fans (15W Each, 10 Fans, 2.5m Apart) with DC Plugs & Sockets

Hello

I have to power several fans that have a 12 V DC motor, the power of one motor is 15 W in total, there are 10 fans to be separated from each of them by about 2.5 m in one row what diameter to use the cable to make it work properly and the cables do not heat up . I will add that it would suit me to use ready-made cables terminated with DC plugs or sockets, and for DC fans use such DC distributors from one socket to two plugs, the fans already have a DC socket in their housing. The entire installation must be easily disassembled due to the change in position or angle of the fan.
My question is whether I could use ready-made wires with a cross-section of 0.18 mm ^ 2 or if they are too thin, you can buy 0.25 mm ^ 2 yet, but this is rare and usually they are thinner. I will add that the whole will be powered by a 12V 15A power supply. Can there be a large voltage drop over the length of the cable to the last fan?

Regards

You have to use different tables depending on the cables used, because 25 m of cable will cause a voltage drop at constant voltage, cross-sections in your post will fall off. http://www.elektryk.kdi.pl/wp-content/uploads/2014/01/obciazenie_ honorow.jpg You have to count it all. The moderator wrote (paper fan and fans).

Hello

I have already seen similar tables, but they refer to alternating current and with alternating current there are much higher powers, e.g. active power P = U * I * cos fi and e.g. for 1 AP = 230 * 1 * 0.8 = 184 W and in my case there will be a 15 A max power supply, but the voltage is 12 V instead of 230 V, i.e. the power will be 10 * 15 W = 150 W or 150/12 = 12.5 A. However, when it comes to distances, when the power supply will be located at the beginning of the whole series so that it could be 25 m, but I thought that it could be equally well positioned in the middle so that there were 5 fans in one direction and 5 in the other, which would shorten the distance to the last fan by half, i.e. about 12.5 m. Is my reasoning is correct Maybe then such cross-sections of wires are enough?

Regards

Quote:

However, when it comes to distances, when the power supply will be located at the beginning of the whole series, it could be 25 m, but I thought that it could be equally well positioned in the middle so that there were 5 fans in one direction and 5 in the other, which would shorten the distance to the last fan by half or about 12.5 m. Is my reasoning correct?

Yes, by the way the load current drops by half.

Quote:

Maybe then such cross-sections of wires are enough?

Rather not, look for tables with the given temperature increase, I found that for an increase of 10 ° C, for the American size AWG 22, i.e. 0.32mm2 max 5A.
Data from such tables should be treated as approximate and compared from several sources, because the temperature depends on the operating conditions of the cable and these data are usually lost as a result of repeated copying on the Internet.

sanmar wrote:

I have already seen similar tables, but they refer to alternating current and with alternating current there are much higher powers, e.g. active power P = U * I * cos fi and e.g. for 1 AP = 230 * 1 * 0.8 = 184 W and in my case there will be a 15 A max power supply, but the voltage is 12 V instead of 230 V, i.e. the power will be 10 * 15 W = 150 W, i.e. 150/12 = 12.5 A.

The load capacity of the cable is the value of the current flowing through it and it does not matter whether it is alternating or direct current.
In the case of alternating current, the difference is only that it is necessary to take into account reactive power, which does not work, but the current, of course, flows and a thicker wire should be used accordingly.
The resistance of a wire with a cross-section of 0.18mm? over a distance of 2.5m is about 0.23?, which gives a voltage drop of almost 3V at 12.5A, for a 0.25mm? cable the voltage drop will be about 2V. Of course, this applies to one vein - you have two, so voltage drops x2.
Here you have a cable resistance calculator depending on the diameter / cross-section (do not mistake it because these are two different things) and the material from which it was made:
http://ekalk.eu/ro_pl.html
The rest is nothing but Ohm's Law.
In your case, for a 12.5A current from the power supply to the branching, use a cable of at least 2x1mm, preferably 1.5mm. You can't skip physics.