How to Properly Power My Project with Three Motors

[03umbe03]

Hi everyone,

I’m a beginner working on a project where I need to control three underwater DC motors (12-16V, 5A, 5000 RPM). I based my circuit design on the motor control setup from this project:

[Arduino Underwater ROV - Science Buddies]

My Setup:

• 3 DC motors (12-16V, 5A, 5000 RPM)

• L293D motor driver to control direction

• Arduino Uno

• LEDs for direction indication (blue = forward, yellow = reverse)

• 9V battery (temporary, just for demonstration purposes, not for actual use)

My Question:

What’s the best way to power this setup?

I know that the 9V battery is not sufficient, but I’m unsure what power source I should use to properly run the motors. Any recommendations would be greatly appreciated!

My Code:

const int tiraPin[3] = {7, 9, 11};
const int spingiPin[3] = {8, 10, 12};

void setup() {
  Serial.begin(9600); // Inizializza la comunicazione seriale

  for (int i=0; i<3; i++) {
    pinMode(tiraPin[i], OUTPUT);
    pinMode(spingiPin[i], OUTPUT);
  }

  pinMode(13, OUTPUT);
}

void loop() {
  for (int i=0; i<3; i++) {
    digitalWrite(tiraPin[i], HIGH);
    digitalWrite(spingiPin[i], LOW);
  }

  delay(1000);

  for (int i=0; i<3; i++) {
    digitalWrite(tiraPin[i], LOW);
    digitalWrite(spingiPin[i], HIGH);
  }

  delay(1000);
}

[GoForSmoke]

You need a battery pack unless you can use a power supply connected to grid power or a generator or PV panel.

I don't know how long your project needs to run so I can't say how many of what kind of batteries you need. For a short demo you might get away with 2 AA's and a DC-DC Boost Converter (95+% efficient, for small current they're cheap) if you need more than 3V. For a real short demo you might get away with a coin cell of sufficient V.

[PaulRB]

Your motors are rated 5A each and you have 3 of them.

Maybe some kind of lead-acid or lithium-ion 12V battery, but check that it is rated for 15A + 20% for safety, and choose the capacity depending on how long you want the project to run between re-charges. Even if on average your motors draw only 2.5A each, you will need a battery with 7.5Ah capacity if you want them to run 1 hour between charges.

Warning 1: a breadboard can carry currents of up to 1A absolute maximum. You need to route the motor current away from your breadboards using suitable gauge wires.

Warning 2: L293D can supply up to 600mA current to a motor, so you need to choose motor drivers with many times higher max current.

[sonofcy]

You will need a BIG battery pack for the underwater motors. Since the battery will be above the water, the wires connecting the battery to the motors will be a loss unless they are very large gauge. You mention 5A, is that for each motor or total? If the total is one kind of battery, if each is a much BIGGER battery.
The UNO can use a small battery pack, maybe one of those USB power packs but the UNO can NOT supply power to anything else in your setup.
As @PaulRB said, that driver is completely useless for those motors. Check the Pololu website for information on motor drivers.

[Terrypin]

Do you realise that you are basing your project on one using toy motors ('thrusters'), probably using mere milliamps?

"- Underwater Thruster: Powerful and unique underwater for your toy."

So if you really are planning for three motors using up to 5A each...

[gilshultz]

@03umbe03

L293D motor driver to control direction

Place them in the trash, they cannot begn to drive your motor(s). Take a look at the BTS7960 module it has a rating greater then the motors so it should work fine. I have had great luck with them. This link may help: https://www.instructables.com/Motor-Driver-BTS7960-43A/