Any switch-mode power supply that supplies 12VDC with 2A (or more) will do fine. Officially the voltage spec is 11-15VDC. I've found no difference from 11.5VDC (battery supply getting low) through to 13.5VDC (regulated vehicle supply).
I also hooked up a power meter to measure power draw at maximum slew and at sidereal tracking: 22W and 11W respectively.
Make sure you get exactly the right connector size (
Edit: and polarity - it's centre positive) and that it's a firm fit - a right-angle connector is best. It's a right royal pain if the connector falls out when slewing!