We bought this inverter 1 year ago with 120 AH battery and till now it works superb without any problem.
But in our region jalandhar, punjab there are no shortage of electricity because we live in railway quarters so for us there is no problem to use this inverter with 120 AH battery, for over electricity shortage region it will be good with 320 AH.So in the end I say that you can go for it. Thanx