I have a NEMA-17 stepper motor (a 12V Mercury Motors SM-42BYG011-25 - https://www.sparkfun.com/datasheets/Robotics/SM-42BYG011-25.pdf) and am trying to pull a slider across a track for a motion time-lapse. I am using a Raspberry Pi Zero with a motor hat: https://www.adafruit.com/products/2348. I had an 8-pack of AA batteries that I was initially using to power the slider, but was not happy with the batteries running low after two runs down the track. I purchased a 7A, 12V rechargeable lead-acid battery, but when I hooked it up, instead of stepping in one direction the motor was fluttering back and forth with significant strength. After about ~10 seconds, a flash and smoke came out of the driver's IC.
I have a spare channel in this motor hat, so it is still usable (I only need one stepper motor attached to it). What went wrong? The motor's max current (according to the Adafruit page I bought it from: https://www.adafruit.com/products/324) is 350 mA and the driver should be able to drive 1.2A at 4.5 to 13.5 volts. Is there any way to hook up a beefier battery to the motor?
Thanks in advance!