# Power Distribution Question

Hello,

My project will consist of almost 100 PC fans, and I am going to control them using an Arduino. Now, I am trying to figure out how to supply enough external power safely and how to divide my circuit. Since it will deal with a lot of currents, I would like to check my plan with you guys before testing it to prevent me from being burned.

Here are the specifics, my plan, and questions. (I’ve also attracted a diagram of my circuit)

1. Each fan consumes 12V and 0.14A. And all fans will be hooked up in parallel.
2. I will use 2 adapters(12V, Max 10A) to safely draw currents from wall outlets.
3. I will use solderless breadboards for my circuit. From what I found, solderless breadboards are recommended under 1A. So, I will make 20 groups of 5 fans for the safe power supply. (0.14*5 = 0.7A)
4. As I use two adapters, one can support 10 groups (7A). Since the breadboards cannot handle 7A, the currents need to be divided before going to each breadboard. So, I am thinking about using terminal blocks distribution to divide current into 10, and I am not sure if I’m going the right way and find the right one.

Could you please look at the terminal block that I found? Will it work for my project? I’ll leave the picture below. And do you see any problems in my plan?

[Terminal Block Distribution >> ]

[just in case, Power Supply Adapter >>]

Thank you.

I do not see any fuses in your layout. Do you ever expect one of your fans to emit smoke? How quickly can you find the correct terminal block and screw set to disconnect it?
Paul

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Welcome to the forum.

Snif snif, can you smell that ? I smell a smoking breadboard, melting breadboard contacts, glowing breadboard wires.

A breadboard can be used for a few leds of 20mA, but only if you are lucky. Breadboards have often bad contacts and are very low quality.

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Should I use fuses to safely supply power even if I divide each current into 700mA? I am a newbie in this area. I don't have electric knowledge...

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So, should I solder with PCB for my circuit? I wanted to use breadboards because I can easily put together and take apart my circuit...

You cannot DIVIDE the current. You are still connecting all the wires to the power supply which can supply up to 2 times 10 amps. ANY ONE of the wires can short and draw the full 10 or 20 amps.
Paul

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Thank you so much.
Sounds like I have the wrong conception of the current and the terminal block distribution. Then, Would there be another way to supply power to 100 pc fans?

Your PC fans likely had a 2-pin connector on each one. That is the correct way to connect so you can easily pull one off when it smokes.
The mating connector is a standard double row of pins like you see on many printed circuit boards. Are you into making your own circuit boards? You can include a connector for a 1 amp fuse for each fan on the same board.
With 100 fans, are you seeing why people use printed circuit boards?
Paul

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I am using the connector of the PC fans, like connecting them to the breadboard using wires. Would it be different from what you meant by "Your PC fans likely had a 2-pin connector on each one. That is the correct way to connect so you can easily pull one off when it smokes."?

I don't have any experience with the printed circuit boards, but I am willing to learn and try if needed. So, instead of using terminal block distribution with breadboards and dividing 100 fans into 20 groups in parallel, I have to use the PCB and connect all fans (also in parallel, in that case, they will draw 14 amps) and should supply power to the PCB?

Lastly, are the PC fans likely to smoke? I thought they would be kind of reliable to turn on and off using an Arduino.

Thank you again. I really appreciate it.

Hi,
Welcome to the forum.

Please read the post at the start of any forum , entitled "How to use this Forum".

Can I suggest first off, get your Arduino code working with ONE fan, to prove that the fan can be controlled.

What model Arduino are you using?

Thanks.. Tom..

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What are you making that needs ~100 individual fans?

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Are ALL your fans identical? Same manufacturer? Same part number? All new? If not, you do know when any one of them could have a heat/electrical problem.
Paul

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@Paul_KD7HB
Yes, they are all identical, same manufacture, and brand new. Seems like I always need to take some problems into account.

@wildbill
I am making artwork using fans, like an installation. Ideally, I want to use 96 fans, but I might end up cutting down if it is not possible...

@TomGeorge
I do Processing and took a basic Arduino course. I learned basic electronics, input/output components(such as sensors, motors, and shift registers) and programming. But I didn't learn how to build PCB...

Yes, I already tested 6 fans connected with an Arduino UNO, MOSFETs, and external power. I was able to control 6 fans all at once. At this moment, I want to see if I really can work with plenty of fans, and I thought the first thing I should figure out is how to supply power to them.

I am thinking about using a shift register to extend I/O pins. Testing it with programming will be the next step. (Arduino MEGA is also on my list) My MOSFETs have seemed fine so far, but as I increase the number of fans, I think I need to double-check them as well...

here's specs of the fans. They use 12V.

Thank you so much all.

What is the third wire for? Are you using it?
Paul

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Take a look at a BTS7960 bridge module, it can be used as a motor driver and drive all the fans even PWM if you want, it is rated at 43A and is under \$10.00 delivered from your favorite china supplier. I would also recommend you get a single power supply in the range of 20 Amps, that is only 240 watts which your mains should have no problem supplying. This will keep everything simple and easy to build. You should calculate the voltage drop on the wiring, you can use more than one supply wire and split the fans maybe 25 to 50 per branch. I do something similar, I have only about 40 fans and it works great, has been for several years.

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Do you mean the third pin of the PCfan? I think it is for RPM, and I am not using it. I only use GND and 12V pins and cut and draw current by connecting them to MOSFETs.

I don't think the fans will run for a long time. At longest, 5 mins or so? and then, turn off and then, turn on again like that. Actually, it is not likely that all fans run at the same time. But I need to consider that scenario just in case.

The MOSFETs and shift registers need to double-check at some point, but I thought I should first figure out how to connect 100 fans and how to supply total 14 amps to my circuit using 1or 2 adapters...

Thank you so much!! I'll check the BTS7960 bridge module.

Does each fan need to have one bridge module? If so, it will cost \$1000 because I am using 100 fans. So, I just wanted to double-check. Is there any cost-efficient way by any chance?

Hi,
Are you going to control their speed or just turn them ON or OFF?

Are you placing the MOSFET in the gnd lead of the fan?

Tom...

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Hi,
I am going to just turn them on and off with some interval(from 5 seconds to several minutes).
Yes, I am connecting the MOSFET to the GND of the fan.

I want to find out the way to only use one or two adapters to power 100 fans.

Thank you.

Hi,
So you will be controlling groups rather than individual fans.

Can I suggest for reliability, even 5 to 10minutes reliability you use proper terminal strips with solder or screw connections.
Using breadboard with Dupont style leads is for short term prototyping, it also relies on you having good quality board and jumpers, most are cheap clones and okay for short term experimentation.

How physically big is the array, wire lengths and connections will need to be considered, if your fan has 25mm leads and you need more length you will need to properly connect the leads.

Tom...

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