I said the max amp usage from what I see on the sticker is 16 amps.How did you determine that it pulls 16 amps@120VAC?
Here is my napkin math.
18 amps @ 55.2VDC = 993.6 dc watts
993.6 dc watts / .75 conversion efficiency = 1324.8 ac watts
1324.8 ac watts / 120VAC = 11.04 amps