Motor dc and l298n

Projects General Guidance
1

hi everyone
i have 2 6 volt dc motors and l298 and 7.5 volts with 5 AA 1.5 volts battery

when im using one of the motors with full speed each motor work
but when im using both of them together i see 2 problems :

first : the speed of each motor is lower than speed of working one motor

second : one of wheels is not working unless i touch and move it manually for starting and then it will work and i test it and switch motors connection and i find out one of motor connector in l298n is having the problem i thought maybe its my l298n has problem but if my connector has problem why is it working

with one motor and not 2 motor together ????????

this is my code for testing :

int ena_right = 3;
int first_pin_right = 4;
int first_pin_left =5 ;

int ena_left = 6;
int sec_pin_right = 7;
int sec_pin_left =8;

void setup()
{
  for (int i = 3 ; i < 9 ; i++)
  {
    pinMode(i,OUTPUT);  
  }

              digitalWrite(first_pin_right,HIGH);
              digitalWrite(first_pin_left,LOW);
              digitalWrite(sec_pin_right,HIGH);
              digitalWrite(sec_pin_left,LOW);

              delay(2000);
              
              analogWrite(ena_right,255);
              delay(2000);
              analogWrite(ena_right,0);
              delay(500);
              analogWrite(ena_left,255);  
              delay(2000);      
              analogWrite(ena_left,0);
              delay(500);
              analogWrite(ena_left,255);
              analogWrite(ena_right,255);
              delay(2000);
              analogWrite(ena_right,0);              
              analogWrite(ena_left,0);

}

void loop()
{  

}
2

The voltage drop across the L298N will increase with current, reducing the voltage left to the motor. These voltage drops are large for these ancient darlington output chips, perhaps 4V or more are lost. They are only really suitable for higher voltages, lower current motors, like 18/24/36V systems.

The lack of voltage across the motors reduces the stall torque they can produce which accounts for the fact that friction is winning for one of the wheels (this one may have a mechanical problem that's increasing the friction).

MOSFET motor drivers can be much more performant, with much lower voltage losses.

3

thank u but there is an other way instead of changing driver ?
like power arduino with battery and power logic circuit of driver with arduino ???

4

and u say about the voltage drops i test it and its about left motor output and im changing the code or switch the motor to motor out put and its all about that left motor output i think its damaged and only can handle 1 motor

5

What is the motor's full load current? Stall current? Are your batteries able to supply that current (times 2)?

6

That tells me that the batteries are having trouble provide the current for two motors.
You should be using alkaline or rechargeable NiMh.
Could also be that the wiring between batteries and L298 is too thin.
It can't AFAIK be the L298, because it's two H-bridges are fully independent of each other.
Leo..

7

its batteries