SparkFun Forums

[barbogliop98]

Hi. I need to buy a stepper Motor, but I need to know it it will work with a AA battery and how long would it work for. I need to use a stepper motor. Where I will be using it there is no electricity so it needs to work on a battery and its far away so it needs to last the longest it can. What do you recommend?

Thank you

[leon_heller]

A stepper motor typically requires a much higher voltage than 1.5V, and takes a lot of current.

[Shifted]

Maybe post some info on what the motor is doing?

Is it moving something heavy? What are the torque requirements? Duty cycle?

But as said above, I doubt you'll find a stepper motor that operates on 1.5v and the current that can be provided by a AA battery.

[DeusExMachinist]

Can someone explain to a complete noob how you would go about selecting a battery for use with the SFE Stepper motor?

[EmbeddedMan]

DeusEx,

Sure thing. First, however, you need to tell us how you'll be driving the motor - what driver chips or other method will you use?

If you use the EasyDriver, then any DC source between 30V and about 8V will work out fine.

As other have said, stepper motors take a lot of current. They are not normally used for battery powered devices because of this fact. (They consume pretty much constant current weather they are moving or not, so take that into consideration.) The SFE stepper motor, driven with an Easy Driver, at maximum current, will consume maybe around 1Amp all the time.

You'll need a large gel-cell, or maybe a battery from a power drill.

*Brian

[DeusExMachinist]

Thanks for the help. I'll be using the easydriver and arduino. How does amperage factor into my selection?

[MichaelN]

For the OP, the mechanism in an "analog" clock is a bit like a stepper motor, and they run for a long time on a AA battery. Depending on what you're trying to do, you may be able to use something similar.

If you post more info on what you're trying to achieve you'll get more response...

[EmbeddedMan]

DeusEx,

The EasyDriver allows you to set the maximum current going into the motors. I've found that even at the minimum current (about 200mA/phase or 400mA total or so) there is plenty of torque from the stepper to do just about anything. My setup is usually a 12V computer power supply, with the EasyDriver set to minimum current. What I'd to is start with that, and if you need to go higher in current (unlikely) you'll want to raise the voltage as well.

*Brian

[waltr]

There are many sizes of stepper motors. I have some very small ones (I think they came from a floppy drive) that are about 1/2 x 1/2 inch and draw about 50mA @ 5V. I also have a couple that are 5in dia by 8 inch long and draw 15Amps @ 5V. Both are bi-polar stepper motors.

To the original poster. First you need to define what you need mechanically.
Speed (rpm), torque, continuous rotation or positioning. Then you can narrow down the possible motors available.

If you need to have it move to a position then stay there a worm gear reducer will hold without power applied and a small stepper with have enough torque due to the speed reduction but will not turn fast. Another stepper positioning mechanism is a screw to produce a linear motion This would also hold without power.

Depending on what you want this motor to do it could be operated from a small battery pack or not.