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I'm actually new to using arduino , and trying to make a simple car, using two dc motors, a l298n and an arduino, the problem is that a 9v battery doesn't seem enough to just power the l298n and one dc motor , but in the internet some people use an 4AA battery which is 6v and power the arduino 4 dc motors and the l298n so how ?

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3 Answers 3

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I understand you situation completely as I had also previously experienced the same problem. 9 V batteries are not enough to get the job done.

Therefore, I suggest you to use two 3.7 V Batteries. These batteries are a great alternative and had solved my problem. I hope it will do the same to you.

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The name Arduino refers to dozens if not hundreds of different board and processor designs. Since a specific board / processor was not asked about we can only talk in generic terms.

Almost all Arduinos run at either 5 Volts or 3.3 Volts and contain a regulator to convert a wide range of Voltages to this value. That said, these regulators need a minimal drop between the input voltage and the desired regulated voltage in order to operate. Some require less and are referred to as LDO or Low Drop Out regulators.

As a worse case, consider if this Arduino does not use an LDO regulator and operates at 5 Volts. The difference between the 6 Volt input and Arduino operating Voltage is only 1 Volt. Further, consider if the batteries were not fresh and were only supplying, say, 5.5 Volts. Finally, consider if one or both motors started drawing heavy current from the batteries causing a further drop in Voltage. Any of these cases could cause the Arduino to reset / behave unexpectedly.

Consider trying to use the 9 Volt battery to power the Arduino and the 6 Volt battery to power the motors.

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To properly answer your question instead of taking a SWAG as I did would Be for you to post links giving technical information on each of the hardware devices and which Arduino you are using.

Nine Volt (smoke alarm) batteries do not have enough power to properly power an Arduino. Use some larger cells. There are so many places that show this improper configuration, it just will not last if it even works for a short while. Great for the battery manufacturers.

You can also purchase a SEPIC converter for a few bucks, this is a combination Buck/Boost converter. You set the output voltage you want and it will maintain it as long as you're getting the minimum voltage from the battery, even if the battery is at 3.5V and the output is at 5V. The input will range from about 3V to 30V and it will maintain its setpoint. This range is dependent on the device you pick.

The L298N is about the worce choice you can make for the motor driver. It has darlington bipolar outputs, that drop about 1.4 volts per lead or 2.8 - 3.2 volts to the motor depending on the load. That voltage drop is burnt up as heat and is doing nothing useful. Purchase an H-Bridge that is large enough to drive the motor that has MOSFET outputs, you will be much happier with that.

For batteries use whatever is convenient, the SEPIC converter solves that problem. Best to pick them to power the motor and use the SEPIC to power the Arduino Vin pin at about 7.5V. Doing it via the Vin is not as efficient as doing a 5V direct but you get the additional filtering on that input circuit. A lot depends on which Arduino we are talking about. Since you did not mention one I am assuming either a UNO or Nano.

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