Not providing the full power from battery

If I run the motor with battery it runs in high speed. Again with the Arduino board it slows down the speed. I am using digitalWrite(); What might be the problem?

I have 12V lead acid battery of 1.3AH.

Show us how you have it connected.


Lets hope you have a motor controller such as a Arduino motor shield....

Motors cannot be driven from a logic signal, thats like using a piece of cotton to tow a lorry.

Many cheap motor controllers use Darlington drivers (L293D and L298 are the most common examples). These throw away 2.5 to 3V and are old technology.

If you're using digitalWrite() to apply power to the motor it's only going to be 5V regardless of the voltage you apply to the Arduino. (Not to mention current considerations and back emf when you turn the motor off.)

Or do you mean you use digitalWrite() to switch the 12V power with a driver as MarkT wonders? (In fact a 298 loses almost 5V at higher current.)

But since you haven't shown your circuit, we're guessing.....

This is what I connected the things.

abish_r01: This is what I connected the things.

Ok well then it's as MarkT guessed, and you're throwing away a bunch of volts through the 293. That loss is an inherent feature of the 293's technology.

What is a better bridge driver to use?


weedpharma: What is a better bridge driver to use?

Pololu 2130 maybe, but they have a whole bunch with different voltage and current characteristics.

There's no point recommending a motor driver till we know the specs of the motor....

I bought motors from local market. In the motors no company name is specified. But it is a 500rpm motor with 7KG torque. Then what motor driver is suitable to run both motors.

@JimboZA and MarkT...

Will the same code run with this motor driver you are mentioned above? Will the Arduino UNO and the Pololu 2130 motor driver combination works fine?