L298N Motor Driver with 9.0V DC Motors

Other Hardware Motors, Mechanics, Power and CNC
1

I am trying to use an Arduino UNO, an L298N, and 6 AA batteries to power 2 9.0V DC motors from OSEPP. I at first thought the motors were 5 volts so I was confused why it wasn't working but now that I know they're 9 volts it makes a little bit more sense. The reason I'm confused is that the robot is from an OSEPP kit so why would they package it with 2 9V motors and a battery pack that only provides 7.2 volts? Also, before I try getting more voltage, can the L298N motor driver even supply enough power to get both motors running at top speed?

This is the closest thing I could find to the motors I'm using: https://www.insplay.eu/en_US/shop/product/95052-a-set-of-motors-with-25mm-9v-185rpm-optical-encoders-3339#slogan

2

The L298 is an extremely inefficient dinosaur.

Use a modern motor driver to get full power to the motors. Pololu has the best selection.

3

Do you think there is anything weird about the motors or is the driver the only problem?

4

You haven't told us anything about the motors, other than they resemble some other motors.

To choose the appropriate motor driver you need to know the start/stall current, which is typically about 10X the free running (no load) current.

1 Like
5

You will need 9vdc at the output of the L298N, and some substantial current, probably.

6 batteries x 1.5vdc/battery = 9vdc

The L298N drops (consumes) 1.5vdc from 9vdc leaves your two 9vdc motors with only 7.5vdc

6

Much worse than that.

The L298N internally drops 3 to 5V at high load, so it can waste around half the battery voltage, powered by 9V.

From the L298N data sheet:

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Note that even this is deceptive. With steady state current draw just over 1 A, the L298N starts to heat up and shut down.

7

They look similar but they also share specs. The motor I have says this: "25MM DC MOTOR DC 9.0V 185RPM+/-10% Gear Ratio 1:45"

8

So the problem is that I don't have enough voltage, and it's because of the motor driver, not the batteries or the motors?

9

Which one would you recommend? Or how should I choose one?

10

To make an informed choice more information is required. However I imagine that this Pololu driver would handle one of those motors

11

I would do some troubleshooting before you spend more money on something that also may not work.

Many people have successfully used the L298 driver with toy robots.

FYI: 6 AA = 9V

12

The L298N can drive 9V motors but isn't very efficient, and the 7.2V battery may not provide enough power. A 9V or 12V battery could help. Have you thought about using a more efficient motor driver like a MOSFET-based one?

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