How many amps does it draw when in use? Can you leave the batteries on the charger?

If SeattleSawdust is correct about the wattage draw of 1600, then it is very easy to calculate the amperage draw, just divide the watts by the volts to get the amps. 1600/120 = 13.3 amps. So any 15 amp circuit should be fine as long as nothing else is running on the same circuit.

Manual says charger input is 120V~, 60Hz, 1600W. The charger is used with the riding mower and the batteries are installed in mower when charging.