Better plan on the "multiples".X2 on the Milwaukee should make one of these. A 12AH on the bottom of the pistol grip with the option of hooking up an umbilical cord to a remote 12AH, or multiples.
20V x 12AH = 240 WH = 0.24 kWH
4.6kW input at full chooch = .05 hours (3.13 minutes) of run time and a smokin' battery.