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Topic: Powering Stepper Motor: Battery or Driver issue? (Read 130 times) previous topic - next topic


Hello all,

I am new to using stepper motors, and I am currently unable to even get my stepper motor to move.

I have a setup similar to this one:

The main difference is that I replace the 12V power supply with a 12V Lead battery, 7 Amps.

Also, the motor ratings I have are for a Nema 17 2 phase stepper motor, with 2.0A/phase and 2.2V/phase.

My first question is that since it is a 2 phase motor, do I need to supply 4A and 4.4V to this motor?

Second, my knowledge of current is that only as much current is drawn as needed, so is the 7AH an issue?

Third, or is the issue the fact that the EasyDriver I'm wiring through limits the current to 750mAH the problem? Would something like this driver be better, especially if I want to move up to a Nema 23 motor? (https://www.amazon.com/SMAKN-Upgraded-Version-Segments-Stepper/dp/B016ZJS1FA/ref=pd_cp_60_1?_encoding=UTF8&pd_rd_i=B016ZJS1FA&pd_rd_r=ZXMC08T9F31FE2H8HEMV&pd_rd_w=7SNec&pd_rd_wg=u7vD2&psc=1&refRID=ZXMC08T9F31FE2H8HEMV)

I appreciate all help!


The stepper driver you linked to would be much more suitable for a 2 amp motor. An Easydriver or even a BigEasydriver cannot provide enough current.

The 12v battery should be fine - at least while it is well charged. The 7Ah figure is a measure of its capacity, not its ability to provide current. It can probably provide 10 or 20 amps easily if required - but not for very long. You should also assume that the actual capacity of the battery is only 50% of the sticker value

However stepper motors work better when you use a higher voltage - the driver in your link can work with 40v. I suggest to think seriously about using 24v.

Also post links the the datasheets for your stepper motors. Nema 17 and Nema 23 only tell you the size of the from face (1.7 inches)

This Simple Stepper Code can be sued for testing

Stepper Motor Basics

Two or three hours spent thinking and reading documentation solves most programming problems.


Thank you for the help!

I posted the specs I thought was useful, but here are the datasheets for the motors I am using:

Nema 17:

Nema 23:

From documentation I still wasn't able to figure out what current/phase or voltage/phase means when the motor is actually drawing power.


Don't forget to set the current limiter on the driver to suit the motor.  :)


My first question is that since it is a 2 phase motor, do I need to supply 4A and 4.4V to this motor?

No, the current is 2A - that's the max amplitude of the current in any winding when that winding is
fully driven (depends on the (micro)stepping position when the maximum is).

You don't supply voltage to the motor, the chopper driver provides current to the motor, the voltage is
dependent on the motor speed mostly.
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