the charger that came with my 48V 18AH battery says 55V at 2.0 amps output, 100-240VAC max 2.5A input. it takes about 9-10 hours to fully charge the battery pack when its run down to 0-1 bar. 55V at 2.0A is 110 watts, so allowing for conversion efficiency, I'd peg it at 120-150 watts input, the 2.5A max input is probably inrush current when its first plugged in, and then only at the 100VAC minimum input, at our 120VAC US power, I'd expect less..

I probably should plug it into one of my mFi Power plugs that will graph the power used, next time I charge the batt.

edit: ok, ran the bike at full throttle for a couple miles including up a steep hill, and the charger is pulling 122 watts. thats just barely in range of a cigar plug based inverter (IMHO, cigar plugs are 10A max).

after 20 minutes, the power started dropping fairly quickly, and 15 minutes later is under 70W