Whatever the source of electricity, we recommend using batteries between the source and the motor. So if you want to use AC, we recommend using the AC to charge batteries and using those to drive the motor.
If you run direct, the converter you use must have an output no less than 20 amps 12VDC. This amperage, higher than you might have expected, is due to uncertainty over internal inefficiencies with the converter. The converter must be able to deal with the amperage draw spike from the motor during the work portion of the operating cycle. Batteries handle this draw spike with no problem.
Batteries, of course, also the advantage of giving you reserve power when there is an outage.
If you run out of power — Hand-operation and motor operation are easily and quickly interchangeable, giving you even greater convenience and security for your water supply. The Simple Pump is actually unique in this regard.