easy

Quick question guys! If I have a 12V battery solar system, can I use a 48V battery to pull power from once my 12V battery starts to get low?? So in other words once the 12V battery gets low can I parallel tie it to the 48V battery as long as I’m not charging the 12V battery. Will it allow the inverter to run while the 12v battery is pulling power from the 48v battery??           Appreciate all your answers in advance!