I will set up a system that includes one main power ( 24 Vdc ) and back up battery( 12Vx2 ) . Main line ( 220 Vac go through ac/dc converter and 24 Vdc that we use ) and back up line ( 220 Vac go through 2x( 12V 120Ah battery and battery charger) ). I add diode in front of battery to protect them from inrush current ( approx. 200A, system normally draws 30-40 A ). But I find one diode to use in my country because of limited time. I dont know it could be use for that purpose. Or you can give another ideas for reverse current protection?