rcatank:
PSU is a 10v 600mA wall wart, but the DRV8825 only seems to draw 160mA.
If think about it 160mA must be meaningless because your motor needs to draw up to 1.8 amps (or whatever your current limit is set at).
I am thinking do I need to upgrade my PSU to a higher amperage? Regardless of what VRef is outputting? Some how 160mA draw at VMot is not making sense....
The amount of amps that your power supply can produce has no effect on the voltage that is set by VRef.
10v x 0.6 amps = 6 watts which may be marginal, but I don't think you have told us the coil resistance of your motor so I don't know how many watts the motor needs. If it was my project I would use at least a 12v 1 amp power supply, and 18v or 24v would be better.
You can measure the coil current by putting an ammeter into the coil circuit while the system is de-powered. Just be careful that nothing can disconnect by accident while the power is on.
...R