Permissable Voltage for 5V Bipolar stepper w/ DRV8825 or A4988

Forgive the basic question, stepper motors are a new venture for me. I’ve tried using a DRV8834 powering the motor with 4 Alkaline D cells, but after about 20 minutes the voltage dropped to the point where the motor started skipping steps. I used the D cells because the motor was rated a 5V, but now I know it is possible to run the 5V motor using higher voltage. My problem is; how much more? The motor must be run on battery power and must run continuously for 3 to 4 hours at 5 RPM. I’m thinking about a 12V motorcycle battery, but worry that it might be too much. Here’s what I know from the Motor’s Datasheet:
NEMA 14 with 50:1 gear reduction
Amps/Phase = 0.71
Resistance/Phase = 9.0 ohms
Inductance/Phase = 8.4 mH@1KHz

Will 12V be too much?
Which driver would be best, DRV8825 or A4988?

Correction. I was looking at the wrong datasheet.
NEMA 14 with 50:1 gear reduction
Amps/Phase = 1.00
Resistance/Phase = 3.20 ohms
Inductance/Phase = 4.50 mH@1KHz


Alkaline batteries are not great at supplying high currents, so I am not surprised they did not work well. I would expect something like a small lead-acid battery (which your motorcycle battery probably is) or a LiPo or NiMH battery rated for a few amp-hours to work better.

As long as you are using a driver with active current limiting (like all of our stepper motor drivers) and set the current limit properly, the maximum voltage you can use to power your stepper motor is only limited by what your driver can tolerate. (There is an FAQ on our stepper drivers’ pages that explains this a little more.) Either the A4988 or the DRV8825 would be fine for your operating conditions, although the DRV8825 would give you higher safety margins and has greater microstepping resolution.

- Patrick

Thanks, Patrick. I thought that’s what you would say, but since I’m new at this, I wanted to check.