inputs.text: nice invertercharger used sump pump battery backup - xantrex freedom hf 1800 operating battery backup sumppump basement single submersible pump according inverter draws 500 watts continuous running startup surge probably 1000 1500 watts pump runs fine modifiedsine output inverter connected group 27 marine deep cycle battery via pair 0 awg gauge wires dont go cheap battery cables need pass lot current small voltage drop 10 amps 120vac output would require least 100 amps 12v battery recommend spending extra dollars good 0 gauge copper wires charger set use maximum charge current 40 20 10 2 amps battery charger multistage system trickle charge battery battery fully charged setup options little obscure requires lot button pushing unit seems operate well unit dipswitches behind control panel set type battery use wetcell leadacid gel electrolyte agm type batteries better battery expensive survive chargedischarge cycles minimum would recommend automotive size marine deep cycle battery source not automotive starting battery make sure battery deep cycle rated since needs provide continuous current use sumppump operating 10 time storm would expect 100 amphour battery last 12 15 hours size battery size pump percentage time runs determine battery life overall great solution sump pump backup system provides inverter battery charger transfer switch one package